Re: [SeaBIOS] KVM call agenda for 2013-05-28
Il 02/06/2013 17:05, Gleb Natapov ha scritto: Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. I volunteered to implement this. Why hotplug should generate ACPI code? It does not do so on real HW. Hotplug can do a LoadTable and merge it into the existing ones. But then you do not need QEMU-time generation of tables to do the same thing for cold-plug. Paolo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Sun, Jun 2, 2013 at 2:43 AM, Michael S. Tsirkin m...@redhat.com wrote: On Fri, May 31, 2013 at 01:45:55PM +0200, Laszlo Ersek wrote: On 05/31/13 09:09, Jordan Justen wrote: Why is updating the ACPI tables in seabios viewed as such a burden? Either qemu does it, or seabios... (And, OVMF too, but I don't think you guys are concerned with that. :) I am :) On the flip side, why is moving the ACPI tables to QEMU such an issue? It seems like Xen and virtualbox both already do this. Why is running iasl not an issue for them? I think something was mentioned about iasl having problems on BE machines? I could be easily wrong but I *guess* qemu's hosts x targets (emulate what on what) set is a proper superset of xen's and virtualbox's. Presumably if you want to run an x86 guest on a MIPS host, and also want to build qemu on the same MIPS (or SPARC) host, you'd have to run iasl there too. You guys should take a look at the patch series I posted. That's solved there by the means of keeping iasl output in qemu git tree. configure checks for a working iasl and enables/disables using this pre-processed output accordingly. Everyone developing ASL code would still need working iasl but that's already the case today. I'm sorry the I haven't had time to review your series yet. But, from what you saying about it in this thread, it sounds like a good plan. -Jordan ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Fri, May 31, 2013 at 01:45:55PM +0200, Laszlo Ersek wrote: On 05/31/13 09:09, Jordan Justen wrote: Why is updating the ACPI tables in seabios viewed as such a burden? Either qemu does it, or seabios... (And, OVMF too, but I don't think you guys are concerned with that. :) I am :) On the flip side, why is moving the ACPI tables to QEMU such an issue? It seems like Xen and virtualbox both already do this. Why is running iasl not an issue for them? I think something was mentioned about iasl having problems on BE machines? I could be easily wrong but I *guess* qemu's hosts x targets (emulate what on what) set is a proper superset of xen's and virtualbox's. Presumably if you want to run an x86 guest on a MIPS host, and also want to build qemu on the same MIPS (or SPARC) host, you'd have to run iasl there too. You guys should take a look at the patch series I posted. That's solved there by the means of keeping iasl output in qemu git tree. configure checks for a working iasl and enables/disables using this pre-processed output accordingly. Everyone developing ASL code would still need working iasl but that's already the case today. tables :) Impossible. :) In earnest, I think what we have now is (mostly) correct, just not extensive / flexible enough. No support for PCI hotplug or CPU hotplug, none for S3 (although all of these tie into UEFI deeply), no MTRR setup, no MPTABLE; let alone a non-PIIX chipset. (Well maybe I shouldn't lump these under the ACPI umbrella.) but I haven't seen it as much of a burden. (Of course, Laszlo has helped out with many of the ACPI changes in OVMF, so his opinion should be taken into consideration too. :) It hasn't been a burden in the sense of me not liking the activity; I actually like fiddling with knobs. It has certainly been extra work to bring OVMF's ACPI tables closer to SeaBIOS's functionality / flexibility (and we still lag behind it quite.). Due to licensing differences I can't just port code from SeaBIOS to OVMF (and I never have without explicit permission), so it's been a lot of back and forth with acpidump / iasl -d in guests (massage OVMF, boot guest, check guest dmesg / lspci, dump tables, compare, repeat), brain picking colleagues, the ACPI and PIIX specs and so on. I have a page on the RH intranet dedicated to this. When something around these parts is being changed (or looks like it could be changed) in SeaBIOS, or between qemu and SeaBIOS, I always must be alert and consider reimplementing it in, or porting it with permission to, OVMF. (Most recent example: pvpanic device -- currently only in SeaBIOS.) It worries me that if I slack off, or am busy with something else, or simply don't notice, then the gap will widen again. I appreciate learning a bunch about ACPI, and don't mind the days of work that went into some of my simple-looking ACPI patches for OVMF, but had the tables come from a common (programmatic) source, none of this would have been an issue, and I wouldn't have felt even occasionally that ACPI patches for OVMF were both duplicate work *and* futile (considering how much ahead SeaBIOS was). I don't mind reimplementing stuff, or porting it with permission, going forward, but the sophisticated parts in SeaBIOS are a hard nut. For example I'll never be able to auto-extract offsets from generated AML and patch the AML using those offsets; the edk2 build tools (a project separate from edk2) don't support this, and it takes several months to get a thing as simple as gcc-47 build flags into edk2-buildtools. Instead I have to write template ASL, compile it to AML, hexdump the result, verify it against the AML grammar in the ACPI spec (offsets aren't obvious, BytePrefix and friends are a joy), define initialize a packed struct or array in OVMF, and patch the template AML using fixed field names or array subscripts. Workable, but dog slow. If the ACPI payload came from up above, we might be as well provided with a list of (canonical name, offset, size) triplets, and could perhaps blindly patch the contents. (Not unlike Michael's linker code for connecting tables into a hierarchy.) AFAIK most recently iasl got built-in support for offset extraction (and in the process the current SeaBIOS build method was broken...), so that part might get easier in the future. Oh well it's Friday, sorry about this rant! :) I'll happily do what I can in the current status quo, but frequently, it won't amount to much. Thanks, Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Thu, May 30, 2013 at 10:34:26PM -0400, Kevin O'Connor wrote: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Given the objections to implementing ACPI directly in QEMU, I don't think that's a given, just yet. So far Anthony asked to be shown the kind of project that ACPI generation in QEMU would enable. Since qemu community wasn't directly exposed to the ACPI-related patches it's easy to see how qemu maintainers won't be aware of the churn and maintainance overhead caused by generating them on the guest side. That seems reasonable, so please hang on just a little bit longer until I post acpi hotplug support for pci bridges based on this code. Then we can discuss. -- MST ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, May 29, 2013 at 11:45:44AM +0300, Michael S. Tsirkin wrote: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, complexities in running iasl on big-endian machines, possible complexity of having to regenerate tables on a vm reboot, overall sloppiness of doing it in QEMU. Raised that QOM interface should be sufficient. Kevin believes that the bios table code should be moved up into QEMU. Reasons cited include the churn rate in SeaBIOS for this QEMU feature (15-20% of all SeaBIOS commits since integrating with QEMU have been for bios tables; 20% of SeaBIOS commits in last year), complexity of trying to pass all the content needed to generate the tables (eg, device details, power tree, irq routing), complexity of scheduling changes across different repos and synchronizing their rollout, complexity of implemeting the code in both OVMF and SeaBIOS. Kevin wasn't aware of a requirement to regenerate acpi tables on a vm reboot. I think this last one is based on a misunderstanding: it's based on assumption that we we change hardware by hotplug we should regenerate the tables to match. But there's no management that can take advantage of this. Two possible reasonable things we can tell management: - hotplug for device XXX is not supported: restart qemu to make guest use the device - hotplug for device XXX is supported What is proposed here instead is a third option: - hotplug is supported but device is not functional. reboot guest to make it fully functional This will naturally lead to requirement to regenerate tables on reset. And this is what would happen with guest-generated tables, and I consider this a bug, not a feature. +1. This will probably break guest resume too. If you really wanted to update tables dynamically, without restarting qemu, don't stop there, add an interface for guest to update them without reset. I think that's over-endineering and a requirement that's best avoided. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. -Kevin I volunteered to implement this. Why hotplug should generate ACPI code? It does not do so on real HW. It was also mentioned that this patch does not yet have to fix the cross-version migration issue with fw_cfg. If we agree on a direction, we will fix it then. Lastly, a proposal was made by Michael to make the call bi-weekly instead of weekly, as we were cancelling it too much. There were no objections. Thus, the next call is planned for June 11, 2013. -- MST ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios -- Gleb. ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Sun, Jun 02, 2013 at 06:05:42PM +0300, Gleb Natapov wrote: On Wed, May 29, 2013 at 11:45:44AM +0300, Michael S. Tsirkin wrote: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, complexities in running iasl on big-endian machines, possible complexity of having to regenerate tables on a vm reboot, overall sloppiness of doing it in QEMU. Raised that QOM interface should be sufficient. Kevin believes that the bios table code should be moved up into QEMU. Reasons cited include the churn rate in SeaBIOS for this QEMU feature (15-20% of all SeaBIOS commits since integrating with QEMU have been for bios tables; 20% of SeaBIOS commits in last year), complexity of trying to pass all the content needed to generate the tables (eg, device details, power tree, irq routing), complexity of scheduling changes across different repos and synchronizing their rollout, complexity of implemeting the code in both OVMF and SeaBIOS. Kevin wasn't aware of a requirement to regenerate acpi tables on a vm reboot. I think this last one is based on a misunderstanding: it's based on assumption that we we change hardware by hotplug we should regenerate the tables to match. But there's no management that can take advantage of this. Two possible reasonable things we can tell management: - hotplug for device XXX is not supported: restart qemu to make guest use the device - hotplug for device XXX is supported What is proposed here instead is a third option: - hotplug is supported but device is not functional. reboot guest to make it fully functional This will naturally lead to requirement to regenerate tables on reset. And this is what would happen with guest-generated tables, and I consider this a bug, not a feature. +1. This will probably break guest resume too. If you really wanted to update tables dynamically, without restarting qemu, don't stop there, add an interface for guest to update them without reset. I think that's over-endineering and a requirement that's best avoided. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. -Kevin I volunteered to implement this. Why hotplug should generate ACPI code? It does not do so on real HW. Hotplug should not generate ACPI code. What is meant here is adding ACPI code to support hotplug of devices behind a PCI to PCI bridge. It was also mentioned that this patch does not yet have to fix the cross-version migration issue with fw_cfg. If we agree on a direction, we will fix it then. Lastly, a proposal was made by Michael to make the call bi-weekly instead of weekly, as we were cancelling it too much. There were no objections. Thus, the next call is planned for June 11, 2013. -- MST ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios -- Gleb. ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Sun, Jun 02, 2013 at 06:09:50PM +0300, Michael S. Tsirkin wrote: On Sun, Jun 02, 2013 at 06:05:42PM +0300, Gleb Natapov wrote: On Wed, May 29, 2013 at 11:45:44AM +0300, Michael S. Tsirkin wrote: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, complexities in running iasl on big-endian machines, possible complexity of having to regenerate tables on a vm reboot, overall sloppiness of doing it in QEMU. Raised that QOM interface should be sufficient. Kevin believes that the bios table code should be moved up into QEMU. Reasons cited include the churn rate in SeaBIOS for this QEMU feature (15-20% of all SeaBIOS commits since integrating with QEMU have been for bios tables; 20% of SeaBIOS commits in last year), complexity of trying to pass all the content needed to generate the tables (eg, device details, power tree, irq routing), complexity of scheduling changes across different repos and synchronizing their rollout, complexity of implemeting the code in both OVMF and SeaBIOS. Kevin wasn't aware of a requirement to regenerate acpi tables on a vm reboot. I think this last one is based on a misunderstanding: it's based on assumption that we we change hardware by hotplug we should regenerate the tables to match. But there's no management that can take advantage of this. Two possible reasonable things we can tell management: - hotplug for device XXX is not supported: restart qemu to make guest use the device - hotplug for device XXX is supported What is proposed here instead is a third option: - hotplug is supported but device is not functional. reboot guest to make it fully functional This will naturally lead to requirement to regenerate tables on reset. And this is what would happen with guest-generated tables, and I consider this a bug, not a feature. +1. This will probably break guest resume too. If you really wanted to update tables dynamically, without restarting qemu, don't stop there, add an interface for guest to update them without reset. I think that's over-endineering and a requirement that's best avoided. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. -Kevin I volunteered to implement this. Why hotplug should generate ACPI code? It does not do so on real HW. Hotplug should not generate ACPI code. What is meant here is adding ACPI code to support hotplug of devices behind a PCI to PCI bridge. Ah, OK. This one does not change on reset. -- Gleb. ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Sun, Jun 02, 2013 at 06:40:43PM +0300, Gleb Natapov wrote: On Sun, Jun 02, 2013 at 06:09:50PM +0300, Michael S. Tsirkin wrote: On Sun, Jun 02, 2013 at 06:05:42PM +0300, Gleb Natapov wrote: On Wed, May 29, 2013 at 11:45:44AM +0300, Michael S. Tsirkin wrote: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, complexities in running iasl on big-endian machines, possible complexity of having to regenerate tables on a vm reboot, overall sloppiness of doing it in QEMU. Raised that QOM interface should be sufficient. Kevin believes that the bios table code should be moved up into QEMU. Reasons cited include the churn rate in SeaBIOS for this QEMU feature (15-20% of all SeaBIOS commits since integrating with QEMU have been for bios tables; 20% of SeaBIOS commits in last year), complexity of trying to pass all the content needed to generate the tables (eg, device details, power tree, irq routing), complexity of scheduling changes across different repos and synchronizing their rollout, complexity of implemeting the code in both OVMF and SeaBIOS. Kevin wasn't aware of a requirement to regenerate acpi tables on a vm reboot. I think this last one is based on a misunderstanding: it's based on assumption that we we change hardware by hotplug we should regenerate the tables to match. But there's no management that can take advantage of this. Two possible reasonable things we can tell management: - hotplug for device XXX is not supported: restart qemu to make guest use the device - hotplug for device XXX is supported What is proposed here instead is a third option: - hotplug is supported but device is not functional. reboot guest to make it fully functional This will naturally lead to requirement to regenerate tables on reset. And this is what would happen with guest-generated tables, and I consider this a bug, not a feature. +1. This will probably break guest resume too. If you really wanted to update tables dynamically, without restarting qemu, don't stop there, add an interface for guest to update them without reset. I think that's over-endineering and a requirement that's best avoided. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. -Kevin I volunteered to implement this. Why hotplug should generate ACPI code? It does not do so on real HW. Hotplug should not generate ACPI code. What is meant here is adding ACPI code to support hotplug of devices behind a PCI to PCI bridge. Ah, OK. This one does not change on reset. It wouldn't if QEMU generates it. With bios generating the tables it might depending on how it's implemented. To make it not change across resets we'd need an interface in QEMU to tell guest whether a device was added since QEMU start. -- Gleb. ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Thu, May 30, 2013 at 7:34 PM, Kevin O'Connor ke...@koconnor.net wrote: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Given the objections to implementing ACPI directly in QEMU, one possible way forward would be to split the current SeaBIOS rom into two roms: qvmloader and seabios. The qvmloader would do the qemu specific platform init (pci init, smm init, mtrr init, bios tables) and then load and run the regular seabios rom. With this split, qvmloader could be committed into the QEMU repo and maintained there. This would be analogous to Xen's hvmloader with the seabios code used as a starting point to implement it. I think hvmloader is more closely tied to Xen, than the Xen firmware. I could be wrong, but thought it could do things like add memory to guest machine. ?? I don't think this model is analogous to Xen's model. I view the hvmloader as just a part of Xen. (Not part of the 'firmware' stack.) In adding this pre-firmware firmware, wouldn't Anthony's concern of iasl still be an issue? Why is updating the ACPI tables in seabios viewed as such a burden? Either qemu does it, or seabios... (And, OVMF too, but I don't think you guys are concerned with that. :) On the flip side, why is moving the ACPI tables to QEMU such an issue? It seems like Xen and virtualbox both already do this. Why is running iasl not an issue for them? I think overall I prefer the tables being built in the firmware, despite the extra thrash. Some things, such as the addresses where devices are configured at are re-programmable in QEMU, so a firmware can decide to use a different address, and thus invalidate the address qvmloader had set in the tables. Maybe we are doing lots of things horribly wrong in our OVMF ACPI tables :), but I haven't seen it as much of a burden. (Of course, Laszlo has helped out with many of the ACPI changes in OVMF, so his opinion should be taken into consideration too. :) -Jordan ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Kevin O'Connor wrote: one possible way forward would be to split the current SeaBIOS rom into two roms: qvmloader and seabios. The qvmloader would do the qemu specific platform init (pci init, smm init, mtrr init, bios tables) and then load and run the regular seabios rom. qvmloader sounds a lot like coreboot. qvmloader could be committed into the QEMU repo and maintained there. If QEMU really doesn't want anything besides quacking like a PC with BIOS or UEFI (such as quacking like a PC *without* a particular firmware) it makes perfect sense to me to put the complete firmware code into the QEMU repo and never reuse anything else. After all, that's how the proprietary firmware products are managed. Jordan Justen wrote: Why is updating the ACPI tables in seabios viewed as such a burden? I don't know about burden but to me it just doesn't make any sense to generate ACPI in one component (SeaBIOS) based on configuration for another component (QEMU). ACPI bytes are obviously a function of QEMU configuration. QEMU configuration can be changed through a great many channels, so it makes sense to me that QEMU itself would take care of generating correct ACPI, rather than exporting it's own data structures and pushing the ACPI problem onto the firmware, especially considering the desire for multiple independent firmware implementations. There's some code for dynamic ACPI generation in coreboot already, maybe that can be reused in QEMU to save some effort.. On the flip side, why is moving the ACPI tables to QEMU such an issue? Maybe because it is such a steaming pile that even the place where it belongs doesn't really want it.. I think overall I prefer the tables being built in the firmware, despite the extra thrash. That doesn't make sense to me. :\ Keep in mind: there is firmware and there is firmware.. Some things, such as the addresses where devices are configured at are re-programmable in QEMU, so a firmware can decide to use a different address, and thus invalidate the address qvmloader had set in the tables. ..there is now talk about a first-stage firmware (qvmloader) which does only hardware init, and then jumps into a second-stage firmware (SeaBIOS) which starts the operating system. I don't expect that anyone would argue for the second-stage firmware to generate ACPI tables if the first-stage firmware would be shared across different second-stage implementations. The above is by the way *exactly* the model coreboot uses since 14 years. Please make an ernest effort to *look into and try to reuse* what *is already there* .. The fear of coreboot is truly amazing. //Peter ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/31/13 09:09, Jordan Justen wrote: Why is updating the ACPI tables in seabios viewed as such a burden? Either qemu does it, or seabios... (And, OVMF too, but I don't think you guys are concerned with that. :) I am :) On the flip side, why is moving the ACPI tables to QEMU such an issue? It seems like Xen and virtualbox both already do this. Why is running iasl not an issue for them? I think something was mentioned about iasl having problems on BE machines? I could be easily wrong but I *guess* qemu's hosts x targets (emulate what on what) set is a proper superset of xen's and virtualbox's. Presumably if you want to run an x86 guest on a MIPS host, and also want to build qemu on the same MIPS (or SPARC) host, you'd have to run iasl there too. Maybe we are doing lots of things horribly wrong in our OVMF ACPI tables :) Impossible. :) In earnest, I think what we have now is (mostly) correct, just not extensive / flexible enough. No support for PCI hotplug or CPU hotplug, none for S3 (although all of these tie into UEFI deeply), no MTRR setup, no MPTABLE; let alone a non-PIIX chipset. (Well maybe I shouldn't lump these under the ACPI umbrella.) but I haven't seen it as much of a burden. (Of course, Laszlo has helped out with many of the ACPI changes in OVMF, so his opinion should be taken into consideration too. :) It hasn't been a burden in the sense of me not liking the activity; I actually like fiddling with knobs. It has certainly been extra work to bring OVMF's ACPI tables closer to SeaBIOS's functionality / flexibility (and we still lag behind it quite.). Due to licensing differences I can't just port code from SeaBIOS to OVMF (and I never have without explicit permission), so it's been a lot of back and forth with acpidump / iasl -d in guests (massage OVMF, boot guest, check guest dmesg / lspci, dump tables, compare, repeat), brain picking colleagues, the ACPI and PIIX specs and so on. I have a page on the RH intranet dedicated to this. When something around these parts is being changed (or looks like it could be changed) in SeaBIOS, or between qemu and SeaBIOS, I always must be alert and consider reimplementing it in, or porting it with permission to, OVMF. (Most recent example: pvpanic device -- currently only in SeaBIOS.) It worries me that if I slack off, or am busy with something else, or simply don't notice, then the gap will widen again. I appreciate learning a bunch about ACPI, and don't mind the days of work that went into some of my simple-looking ACPI patches for OVMF, but had the tables come from a common (programmatic) source, none of this would have been an issue, and I wouldn't have felt even occasionally that ACPI patches for OVMF were both duplicate work *and* futile (considering how much ahead SeaBIOS was). I don't mind reimplementing stuff, or porting it with permission, going forward, but the sophisticated parts in SeaBIOS are a hard nut. For example I'll never be able to auto-extract offsets from generated AML and patch the AML using those offsets; the edk2 build tools (a project separate from edk2) don't support this, and it takes several months to get a thing as simple as gcc-47 build flags into edk2-buildtools. Instead I have to write template ASL, compile it to AML, hexdump the result, verify it against the AML grammar in the ACPI spec (offsets aren't obvious, BytePrefix and friends are a joy), define initialize a packed struct or array in OVMF, and patch the template AML using fixed field names or array subscripts. Workable, but dog slow. If the ACPI payload came from up above, we might be as well provided with a list of (canonical name, offset, size) triplets, and could perhaps blindly patch the contents. (Not unlike Michael's linker code for connecting tables into a hierarchy.) AFAIK most recently iasl got built-in support for offset extraction (and in the process the current SeaBIOS build method was broken...), so that part might get easier in the future. Oh well it's Friday, sorry about this rant! :) I'll happily do what I can in the current status quo, but frequently, it won't amount to much. Thanks, Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Kevin O'Connor ke...@koconnor.net writes: On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Given the objections to implementing ACPI directly in QEMU, one possible way forward would be to split the current SeaBIOS rom into two roms: qvmloader and seabios. The qvmloader would do the qemu specific platform init (pci init, smm init, mtrr init, bios tables) and then load and run the regular seabios rom. With this split, qvmloader could be committed into the QEMU repo and maintained there. This would be analogous to Xen's hvmloader with the seabios code used as a starting point to implement it. What about a small change to the SeaBIOS build system to allow ACPI table generation to be done via a plugin. This could be as simple as moving acpi.c and *.dsl into the QEMU build tree and then having a way to point the SeaBIOS makefiles to our copy of it. Then the logic is maintained stays in firmware but the churn happens in the QEMU tree instead of the SeaBIOS tree. Regards, Anthony Liguori With both the hardware implementation and acpi descriptions for that hardware in the same source code repository, it would be possible to implement changes to both in a single patch series. The fwcfg entries used to pass data between qemu and qvmloader could also be changed in a single patch and thus those fwcfg entries would not need to be considered a stable interface. The qvmloader code also wouldn't need the 16bit handlers that seabios requires and thus wouldn't need the full complexity of the seabios build. Finally, it's possible that both ovmf and seabios could use a single qvmloader implementation. On the down side, reboots can be a bit goofy today in kvm, and that would need to be settled before something like qvmloader could be implemented. Also, it may be problematic to support passing of bios tables from qvmloader to seabios for guests with only 1 meg of ram. Thoughts? -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Laszlo Ersek ler...@redhat.com writes: On 05/31/13 15:04, Anthony Liguori wrote: Laszlo Ersek ler...@redhat.com writes: On 05/31/13 09:09, Jordan Justen wrote: Due to licensing differences I can't just port code from SeaBIOS to OVMF soapbox :) Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. It's not optimal for the upstream first principle; still on soapbox OVMF is not Open Source so upstream first doesn't apply. At least, the FAT module is not Open Source. Bullet 8 from the Open Source Definition[1] 8. License Must Not Be Specific to a Product The rights attached to the program must not depend on the program's being part of a particular software distribution. If the program is extracted from that distribution and used or distributed within the terms of the program's license, all parties to whom the program is redistributed should have the same rights as those that are granted in conjunction with the original software distribution. License from OVMF FAT module[2]: Additional terms: In addition to the forgoing, redistribution and use of the code is conditioned upon the FAT 32 File System Driver and all derivative works thereof being used for and designed only to read and/or write to a file system that is directly managed by: Intel’s Extensible Firmware Initiative (EFI) Specification v. 1.0 and later and/or the Unified Extensible Firmware Interface (UEFI) Forum’s UEFI Specifications v.2.0 and later (together the “UEFI Specifications”); only as necessary to emulate an implementation of the UEFI Specifications; and to create firmware, applications, utilities and/or drivers. [1] http://opensource.org/osd-annotated [2] http://sourceforge.net/apps/mediawiki/tianocore/index.php?title=Edk2-fat-driver AFAIK, for the systems that we'd actually want to use OVMF for, a FAT module is a hard requirement. we'd have to backport upstream edk2 patches forever (there's a whole lot of edk2 modules outside of direct OvmfPkg that get built into OVMF.fd -- OvmfPkg only customizes / cherry-picks the full edk2 tree for virtual machines), or to periodically rebase an ever-increasing set of patches. Independently, we need *some* FAT driver (otherwise you can't even boot most installer media), which is where the already discussed worries lie. Whatever solves this aspect is independent of forking all of edk2. It's either Open Source or it's not. It's currently not. I have a hard time sympathesizing with trying to work with a proprietary upstream. Rewriting BSD implementations of everything is silly. Every other vendor that uses TianoCore has a proprietary fork. Correct, but they (presumably) keep rebasing their ever accumulating stuff at least on the periodically refreshed stable edk2 subset (UDK2010, which BTW doesn't include OvmfPkg). This must be horrible for them, but in exchange they get to remain proprietary (which may benefit them commercially). Maintaining a GPL fork seems just as reasonable. Perhaps; diverging from upstream first would hurt for certain. Well I'm suggesting creating a real upstream (that is actually Open Source). Then I'm all for upstream first. In terms of creating a FAT module, the most likely source would seem to be the kernel code and since that's GPL, I don't think it's terribly avoidable to end up with a GPL'd uefi implementation. If that's inevitable, then we're wasting effort by rewriting stuff under a BSD license. Regards, Anthony Liguori /soapbox Thanks for the suggestion :) Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
David Woodhouse dw...@infradead.org writes: On Fri, 2013-05-31 at 08:04 -0500, Anthony Liguori wrote: soapbox Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. Heh. Actually it doesn't need to be a fork. It's modular, and the FAT driver is just a single module. Which is actually included in *binary* form in the EDK2 repository, I believe, and its source code is elsewhere. We could happily make a GPL¹ or LGPL implementation of a FAT module and build our OVMF with that instead, and we wouldn't need to fork OVMF at all. So can't we have GPL virtio modules too? I don't think there's any problem there except for the FAT module. I would propose more of a virtual fork. It could consist of a git repo with the GPL modules + a submodule for edk2. Ideally, there would be no need to actually fork edk2. My assumption is that edk2 won't take GPL code. But does ovmf really need to live in the edk2 tree? If we're going to get serious about supporting OVMF, it we need something that isn't proprietary. -- dwmw2 ¹ If it's GPL, of course, then we mustn't include any *other* binary blobs in our OVMF build. But the whole point in this conversation is that we don't *want* to do that. So that's fine. It's even more fundamental. OVMF as a whole (at least in it's usable form) is not Open Source. Without even tackling the issue of GPL code sharing, that is a fundamental problem that needs to be solved if we're going to serious about making changes to QEMU to support it. I think solving the general problem will also enable GPL code sharing though. Regards, Anthony Liguori ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/31/13 15:04, Anthony Liguori wrote: Laszlo Ersek ler...@redhat.com writes: On 05/31/13 09:09, Jordan Justen wrote: Due to licensing differences I can't just port code from SeaBIOS to OVMF soapbox :) Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. It's not optimal for the upstream first principle; we'd have to backport upstream edk2 patches forever (there's a whole lot of edk2 modules outside of direct OvmfPkg that get built into OVMF.fd -- OvmfPkg only customizes / cherry-picks the full edk2 tree for virtual machines), or to periodically rebase an ever-increasing set of patches. Independently, we need *some* FAT driver (otherwise you can't even boot most installer media), which is where the already discussed worries lie. Whatever solves this aspect is independent of forking all of edk2. Rewriting BSD implementations of everything is silly. Every other vendor that uses TianoCore has a proprietary fork. Correct, but they (presumably) keep rebasing their ever accumulating stuff at least on the periodically refreshed stable edk2 subset (UDK2010, which BTW doesn't include OvmfPkg). This must be horrible for them, but in exchange they get to remain proprietary (which may benefit them commercially). Maintaining a GPL fork seems just as reasonable. Perhaps; diverging from upstream first would hurt for certain. /soapbox Thanks for the suggestion :) Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/31/13 16:08, David Woodhouse wrote: On Fri, 2013-05-31 at 08:04 -0500, Anthony Liguori wrote: soapbox Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. Heh. Actually it doesn't need to be a fork. It's modular, and the FAT driver is just a single module. Which is actually included in *binary* form in the EDK2 repository, I believe, and its source code is elsewhere. Correct. We could happily make a GPL¹ or LGPL implementation of a FAT module and build our OVMF with that instead, and we wouldn't need to fork OVMF at all. Yes, that's one plan, *if* someone can sort out, or is willing to shoulder, the perhaps illogical but still worrisome surroundings of FatPkg / FatBinPkg. (I don't intend to spread FUD!) For example, if your employer authorizes you to implement GplFatPkg from scratch, and distribute it as an external module, I -- as someone without any education in law though -- will give you a standing ovation and buy you a case of beer at KVM Forum 2013. Deal? :) (You proved to have great leverage by getting the efi compat table extended, so... :)) ¹ If it's GPL, of course, then we mustn't include any *other* binary blobs in our OVMF build. But the whole point in this conversation is that we don't *want* to do that. So that's fine. Right. Eg. Shell1 is embedded as a pre-built binary, but that's just convenience, you can build the in-tree Shell2 from source afresh and embed that instead (and ship its source too). Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Laszlo Ersek ler...@redhat.com writes: On 05/31/13 09:09, Jordan Justen wrote: Due to licensing differences I can't just port code from SeaBIOS to OVMF soapbox Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. Rewriting BSD implementations of everything is silly. Every other vendor that uses TianoCore has a proprietary fork. Maintaining a GPL fork seems just as reasonable. /soapbox Regards, Anthony Liguori (and I never have without explicit permission), so it's been a lot of back and forth with acpidump / iasl -d in guests (massage OVMF, boot guest, check guest dmesg / lspci, dump tables, compare, repeat), brain picking colleagues, the ACPI and PIIX specs and so on. I have a page on the RH intranet dedicated to this. When something around these parts is being changed (or looks like it could be changed) in SeaBIOS, or between qemu and SeaBIOS, I always must be alert and consider reimplementing it in, or porting it with permission to, OVMF. (Most recent example: pvpanic device -- currently only in SeaBIOS.) It worries me that if I slack off, or am busy with something else, or simply don't notice, then the gap will widen again. I appreciate learning a bunch about ACPI, and don't mind the days of work that went into some of my simple-looking ACPI patches for OVMF, but had the tables come from a common (programmatic) source, none of this would have been an issue, and I wouldn't have felt even occasionally that ACPI patches for OVMF were both duplicate work *and* futile (considering how much ahead SeaBIOS was). I don't mind reimplementing stuff, or porting it with permission, going forward, but the sophisticated parts in SeaBIOS are a hard nut. For example I'll never be able to auto-extract offsets from generated AML and patch the AML using those offsets; the edk2 build tools (a project separate from edk2) don't support this, and it takes several months to get a thing as simple as gcc-47 build flags into edk2-buildtools. Instead I have to write template ASL, compile it to AML, hexdump the result, verify it against the AML grammar in the ACPI spec (offsets aren't obvious, BytePrefix and friends are a joy), define initialize a packed struct or array in OVMF, and patch the template AML using fixed field names or array subscripts. Workable, but dog slow. If the ACPI payload came from up above, we might be as well provided with a list of (canonical name, offset, size) triplets, and could perhaps blindly patch the contents. (Not unlike Michael's linker code for connecting tables into a hierarchy.) AFAIK most recently iasl got built-in support for offset extraction (and in the process the current SeaBIOS build method was broken...), so that part might get easier in the future. Oh well it's Friday, sorry about this rant! :) I'll happily do what I can in the current status quo, but frequently, it won't amount to much. Thanks, Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, 2013-05-29 at 21:12 -0400, Kevin O'Connor wrote: I remain doubtful that QOM has all the info needed to generate the BIOS tables. Does QOM describe how the 5th pci device uses global interrupt 11 when using global interrupts, legacy interrupt 5 when not using global interrupts, and that the legacy interrupt can be changed by writing to the 0x60 address of the 1st pci device's config space? Does QOM state that the machine supports S3 sleep mode? Does QOM indicate that an IPMI device supports the 3rd version of the IPMI device specification? Does it indicate whether this particular version of qemu has correctly implemented the hard reset at 0xcf9? If so, we need to put that in as the ACPI RESET_REG. It seems that there's a *lot* which isn't fully described in the QOM tree. Do we really want to add it all, just so that ACPI tables can be reliably generated from it? As we add new types of hardware and even fix/adjust features like the examples above, we'll also have to implement the translation from QOM to ACPI tables. And we'll have to do so in more than one place, in projects with a completely different release cycle. This would be *so* much easier if the code which actually generates the ACPI tables was *in* the qemu tree along with the hardware that those tables describe. -- dwmw2 smime.p7s Description: S/MIME cryptographic signature ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/31/13 16:38, Anthony Liguori wrote: It's either Open Source or it's not. It's currently not. I disagree with this binary representation of Open Source or Not. If it weren't (mostly) Open Source, how could we fork (most of) it as you're suggesting (from the soapbox :))? I have a hard time sympathesizing with trying to work with a proprietary upstream. My experience has been positive. First of all, whether UEFI is a good thing or not is controversial. I won't try to address that. However UEFI is here to stay, machines are being shipped with it, Linux and other OSen try to support it. Developing (or running) an OS in combination with a specific firmware is sometimes easier / more economic in a virtual environment, hence there should be support for qemu + UEFI. It is this mindset that I operate in. (Oh, I also forgot to mention that this task has been assigned to me by my superiors as well :)) Jordan, the OvmfPkg maintainer is responsive and progressive in the true FLOSS manner (*), which was a nice surprise for a project whose coding standards for example are made 100% after Windows source code, and whose mailing list is mostly subscribed to by proprietary vendors. Really when it comes to OvmfPkg patches the process follows the normal FLOSS development model. (*) Jordan, I hope this will prompt you to merge VirtioNetDxe v4 real soon now :) I personally think the 2-clause BSDL for 99% of the project was a very sane and practical one from Intel et al. FatPkg is a sad exception. One might even consider it a bad accident: http://thread.gmane.org/gmane.comp.bios.tianocore.devel/1861/focus=1878 I have no idea how that selection process went down, but I assume if FLOSS people had been screaming very loud at that time and had offered a *simple* (which ext2 is not, I gather), wide-spread and unencumbered filesystem, things would be different today. In terms of creating a FAT module, the most likely source would seem to be the kernel code and since that's GPL, I don't think it's terribly avoidable to end up with a GPL'd uefi implementation. If that's inevitable, then we're wasting effort by rewriting stuff under a BSD license. Please ask your employer if they'd be willing to put their name on an original, clean-room, GPL-licensed implementation of FAT32 for UEFI. Thus far we've been talking copyright rather than patents, but there's also this: http://en.wikipedia.org/wiki/FAT_filesystem#Challenge http://en.wikipedia.org/wiki/FAT_filesystem#Patent_infringement_lawsuits It almost doesn't matter who prevails in such a lawsuit; the *possibility* of such a lawsuit gives people cold feet. Blame the USPTO. Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/31/13 17:43, Anthony Liguori wrote: David Woodhouse dw...@infradead.org writes: On Fri, 2013-05-31 at 08:04 -0500, Anthony Liguori wrote: soapbox Fork OVMF, drop the fat module, and just add GPL code. It's an easily solvable problem. Heh. Actually it doesn't need to be a fork. It's modular, and the FAT driver is just a single module. Which is actually included in *binary* form in the EDK2 repository, I believe, and its source code is elsewhere. We could happily make a GPL¹ or LGPL implementation of a FAT module and build our OVMF with that instead, and we wouldn't need to fork OVMF at all. So can't we have GPL virtio modules too? I don't think there's any problem there except for the FAT module. I share your assessment. I would propose more of a virtual fork. It could consist of a git repo with the GPL modules + a submodule for edk2. Ideally, there would be no need to actually fork edk2. Indeed. edk2 is extremely modular. But in order to get a useful firmware image ultimately, you need a FAT driver. My assumption is that edk2 won't take GPL code. Correct, see eg. OvmfPkg/Contributions.txt. Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/31/13 18:33, David Woodhouse wrote: On Fri, 2013-05-31 at 10:43 -0500, Anthony Liguori wrote: It's even more fundamental. OVMF as a whole (at least in it's usable form) is not Open Source. The FAT module is required to make EDK2 usable, and yes, that's not Open Source. So in a sense you're right. But we're talking here about *replacing* the FAT module with something that *is* open source. And the FAT module isn't a fundamental part of EDK2; it's just an optional module that happens to be bundled with the repository. Yes. *Some* FAT module is a hard requirement. So I think you're massively overstating the issue. OVMF/EDK2 *is* Open Source, Agreed, and replacing the FAT module really isn't that hard. technically it's not hard; for a seasoned file system developer (which I'm not, of course), even possibly missing UEFI bits, it should be children's play actually, considering the high quality of UEFI documentation and the responsiveness of edk2-devel. Considering US legal climate however, it appears *extremely* hard to replace the FAT module, in my unwashed personal opinion. Laszlo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
David Woodhouse dw...@infradead.org writes: On Fri, 2013-05-31 at 10:43 -0500, Anthony Liguori wrote: It's even more fundamental. OVMF as a whole (at least in it's usable form) is not Open Source. The FAT module is required to make EDK2 usable, and yes, that's not Open Source. So in a sense you're right. But we're talking here about *replacing* the FAT module with something that *is* open source. And the FAT module isn't a fundamental part of EDK2; it's just an optional module that happens to be bundled with the repository. So *if* we replace the FAT module *and* that replacement was GPL, would there be any objects to having more GPL modules for things like virtio, ACPI, etc? And would that be doable in the context of OVMF or would another project need to exist for this purpose? So I think you're massively overstating the issue. OVMF/EDK2 *is* Open Source, and replacing the FAT module really isn't that hard. We can only bury our heads in the sand and ship qemu with non-EFI-capable firmware for so long... Which is why I think we need to solve the real problem here. I *know* there's more work to be done. We have SeaBIOS-as-CSM, Jordan has mostly sorted out the NV variable storage, and now the FAT issue is coming up to the top of the pile. But we aren't far from the point where we can realistically say that we want the Open Source OVMF to be the default firmware shipped with qemu. Yes, that's why I'm raising this now. We all knew that we'd have to talk about this eventually. Regards, Anthony Liguori -- dwmw2 ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Il 31/05/2013 19:06, Anthony Liguori ha scritto: David Woodhouse dw...@infradead.org writes: On Fri, 2013-05-31 at 10:43 -0500, Anthony Liguori wrote: It's even more fundamental. OVMF as a whole (at least in it's usable form) is not Open Source. The FAT module is required to make EDK2 usable, and yes, that's not Open Source. So in a sense you're right. But we're talking here about *replacing* the FAT module with something that *is* open source. And the FAT module isn't a fundamental part of EDK2; it's just an optional module that happens to be bundled with the repository. So *if* we replace the FAT module *and* that replacement was GPL, would there be any objects to having more GPL modules for things like virtio, ACPI, etc? And would that be doable in the context of OVMF or would another project need to exist for this purpose? I don't think it would be doable in TianoCore. I think it would end up either in distros, or in QEMU. A separate question is whether OVMF makes more sense as part of TianoCore or rather as part of QEMU. With 75% of the free hypervisors now reunited under the same source repository, the balance is tilting... Paolo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Paolo Bonzini pbonz...@redhat.com writes: Il 31/05/2013 19:06, Anthony Liguori ha scritto: David Woodhouse dw...@infradead.org writes: On Fri, 2013-05-31 at 10:43 -0500, Anthony Liguori wrote: It's even more fundamental. OVMF as a whole (at least in it's usable form) is not Open Source. The FAT module is required to make EDK2 usable, and yes, that's not Open Source. So in a sense you're right. But we're talking here about *replacing* the FAT module with something that *is* open source. And the FAT module isn't a fundamental part of EDK2; it's just an optional module that happens to be bundled with the repository. So *if* we replace the FAT module *and* that replacement was GPL, would there be any objects to having more GPL modules for things like virtio, ACPI, etc? And would that be doable in the context of OVMF or would another project need to exist for this purpose? I don't think it would be doable in TianoCore. I think it would end up either in distros, or in QEMU. As I think more about it, I think forking edk2 is inevitable. We need a clean repo that doesn't include the proprietary binaries. I doubt upstream edk2 is willing to remove the binaries. But this can be quite simple using a combination of git-svn and a rewriting script. We did exactly this to pull out the VGABios from Bochs and remove the binaries associated with it. It's 100% automated and can be kept in sync via a script on qemu.org. A separate question is whether OVMF makes more sense as part of TianoCore or rather as part of QEMU. I'm not sure if qemu.git is the right location, but we can certainly host an ovmf.git on qemu.git that embeds the scrubbed version of edk2.git. Of course, this would enable us to add GPL code (including a FAT module) to ovmf.git without any impact on upstream edk2. With 75% of the free hypervisors now reunited under the same source repository, the balance is tilting... insert evil laugh :-) Regards, Anthony Liguori Paolo ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Fri, May 31, 2013 at 7:38 AM, Anthony Liguori anth...@codemonkey.ws wrote: In terms of creating a FAT module, the most likely source would seem to be the kernel code and since that's GPL, I don't think it's terribly avoidable to end up with a GPL'd uefi implementation. Why would OpenBSD not be a potential source? http://www.openbsd.org/cgi-bin/cvsweb/src/sys/msdosfs/ We have a half-done ext2 fs from GSoC2011 that started with OpenBSD. https://github.com/the-ridikulus-rat/Tianocore_Ext2Pkg If that's inevitable, then we're wasting effort by rewriting stuff under a BSD license. Regards, Anthony Liguori ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Fri, May 31, 2013 at 11:35 AM, Anthony Liguori anth...@codemonkey.ws wrote: As I think more about it, I think forking edk2 is inevitable. We need a clean repo that doesn't include the proprietary binaries. I doubt upstream edk2 is willing to remove the binaries. No, probably not unless a BSD licensed alternative was available. :) But, in thinking about what might make sense for EDK II with git, one option that should be considered is breaking the top-level 'packages' into separate sub-modules. I had gone so far as to start pushing repos as sub-modules. But, as the effort to convert EDK II to git has stalled (actually never even thought about leaving the ground), I abandoned that approach and went back to just mirroring one EDK II. I could fairly easily re-enable mirror the sub-set of packages needed for OVMF. So, in that case, the FatBinPkg sub-module could easily be dropped from a tree. But this can be quite simple using a combination of git-svn and a rewriting script. We did exactly this to pull out the VGABios from Bochs and remove the binaries associated with it. It's 100% automated and can be kept in sync via a script on qemu.org. I would love to mirror the BaseTools as a sub-package without all the silly windows binaries... What script did you guys use? -Jordan ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Jordan Justen jljus...@gmail.com writes: On Fri, May 31, 2013 at 11:35 AM, Anthony Liguori anth...@codemonkey.ws wrote: As I think more about it, I think forking edk2 is inevitable. We need a clean repo that doesn't include the proprietary binaries. I doubt upstream edk2 is willing to remove the binaries. No, probably not unless a BSD licensed alternative was available. :) But, in thinking about what might make sense for EDK II with git, one option that should be considered is breaking the top-level 'packages' into separate sub-modules. I had gone so far as to start pushing repos as sub-modules. But, as the effort to convert EDK II to git has stalled (actually never even thought about leaving the ground), I abandoned that approach and went back to just mirroring one EDK II. I could fairly easily re-enable mirror the sub-set of packages needed for OVMF. So, in that case, the FatBinPkg sub-module could easily be dropped from a tree. But this can be quite simple using a combination of git-svn and a rewriting script. We did exactly this to pull out the VGABios from Bochs and remove the binaries associated with it. It's 100% automated and can be kept in sync via a script on qemu.org. I would love to mirror the BaseTools as a sub-package without all the silly windows binaries... What script did you guys use? We did this in git pre-history, now git has a fancy git-filter-branch command that makes it a breeze: http://git-scm.com/book/ch6-4.html Regards, Anthony Liguori -Jordan ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Fri, May 31, 2013 at 10:13:34AM +0200, Peter Stuge wrote: Kevin O'Connor wrote: one possible way forward would be to split the current SeaBIOS rom into two roms: qvmloader and seabios. The qvmloader would do the qemu specific platform init (pci init, smm init, mtrr init, bios tables) and then load and run the regular seabios rom. qvmloader sounds a lot like coreboot. Agreed. I don't much like the qvmloader idea. I did want to open up discussion on the possibility, however. The only advantage it has over coreboot is that it could reasonably live in the qemu repo, and I do think that the hardware descriptions should like in the same code repo as the hardware implementation. -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Hi, Raised that QOM interface should be sufficient. Agree on this one. Ideally the acpi table generation code should be able to gather all information it needs from the qom tree, so it can be a standalone C file instead of being scattered over all qemu. Ack. So my basic argument is why not expose the QOM interfaces to firmware and move the generation code there? Seems like it would be more or less a copy/paste once we had a proper implementation in QEMU. Well, no. Firmware is a quite simple environment without standard libc etc, so moving code from qemu to firmware certainly isn't as easy as copying over a file. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. Certainly an option, but that is a long-term project. Out of curiousity, are there other benefits to using coreboot as a core firmware in QEMU? Short-term it's alot of work as we have to bring coreboot's qemu support to feature parity with seabios. I suspect most of this is acpi related though, so when qemu provides the tables and coreboot uses them we could be pretty close already. Long-term it should simplify firmware maintainance as we have only *one* place which handles the hardware bringup, and seabios/ovmf have less work to do. Is there a payload we would ever plausibly use besides OVMF and SeaBIOS? I wouldn't be surprised if people start using other coreboot payloads and/or features such as direct linux kernel boot once it works well on qemu. We might even run qemu test suites as coreboot payload. cheers, Gerd ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, 2013-05-29 at 11:18 -0500, Anthony Liguori wrote: Certainly an option, but that is a long-term project. Out of curiousity, are there other benefits to using coreboot as a core firmware in QEMU? Is there a payload we would ever plausibly use besides OVMF and SeaBIOS? I like the idea of using Coreboot on the UEFI side — if the most actively used TianoCore platform is CorebootPkg instead of OvmfPkg, that makes it a lot easier for people using *real* hardware with Coreboot to use TianoCore. And it helps to dispel the stupid misconception in some quarters that Coreboot *competes* with UEFI and thus cannot possibly be supported because helping something that competes with UEFI would be bad. Is there a payload we would ever plausibly use besides OVMF and SeaBIOS? For my part I want to get to the point where the default firmware shipped with qemu can be OVMF. We have SeaBIOS-as-CSM working, which was one of the biggest barriers. There are a few more things (like NV variable storage, in particular) that I need to fix before I can actually make that suggestion with a straight face though... -- dwmw2 smime.p7s Description: S/MIME cryptographic signature ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Given the objections to implementing ACPI directly in QEMU, one possible way forward would be to split the current SeaBIOS rom into two roms: qvmloader and seabios. The qvmloader would do the qemu specific platform init (pci init, smm init, mtrr init, bios tables) and then load and run the regular seabios rom. With this split, qvmloader could be committed into the QEMU repo and maintained there. This would be analogous to Xen's hvmloader with the seabios code used as a starting point to implement it. With both the hardware implementation and acpi descriptions for that hardware in the same source code repository, it would be possible to implement changes to both in a single patch series. The fwcfg entries used to pass data between qemu and qvmloader could also be changed in a single patch and thus those fwcfg entries would not need to be considered a stable interface. The qvmloader code also wouldn't need the 16bit handlers that seabios requires and thus wouldn't need the full complexity of the seabios build. Finally, it's possible that both ovmf and seabios could use a single qvmloader implementation. On the down side, reboots can be a bit goofy today in kvm, and that would need to be settled before something like qvmloader could be implemented. Also, it may be problematic to support passing of bios tables from qvmloader to seabios for guests with only 1 meg of ram. Thoughts? -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Tue, May 28, 2013 at 07:53:09PM -0400, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, complexities in running iasl on big-endian machines, possible complexity of having to regenerate tables on a vm reboot, overall sloppiness of doing it in QEMU. Raised that QOM interface should be sufficient. Kevin believes that the bios table code should be moved up into QEMU. Reasons cited include the churn rate in SeaBIOS for this QEMU feature (15-20% of all SeaBIOS commits since integrating with QEMU have been for bios tables; 20% of SeaBIOS commits in last year), complexity of trying to pass all the content needed to generate the tables (eg, device details, power tree, irq routing), complexity of scheduling changes across different repos and synchronizing their rollout, complexity of implemeting the code in both OVMF and SeaBIOS. Kevin wasn't aware of a requirement to regenerate acpi tables on a vm reboot. I think this last one is based on a misunderstanding: it's based on assumption that we we change hardware by hotplug we should regenerate the tables to match. But there's no management that can take advantage of this. Two possible reasonable things we can tell management: - hotplug for device XXX is not supported: restart qemu to make guest use the device - hotplug for device XXX is supported What is proposed here instead is a third option: - hotplug is supported but device is not functional. reboot guest to make it fully functional This will naturally lead to requirement to regenerate tables on reset. And this is what would happen with guest-generated tables, and I consider this a bug, not a feature. If you really wanted to update tables dynamically, without restarting qemu, don't stop there, add an interface for guest to update them without reset. I think that's over-endineering and a requirement that's best avoided. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. -Kevin I volunteered to implement this. It was also mentioned that this patch does not yet have to fix the cross-version migration issue with fw_cfg. If we agree on a direction, we will fix it then. Lastly, a proposal was made by Michael to make the call bi-weekly instead of weekly, as we were cancelling it too much. There were no objections. Thus, the next call is planned for June 11, 2013. -- MST ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On 05/29/13 01:53, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, I fail to see the security issues here. It's not like the apci table generation code operates on untrusted input from the guest ... complexities in running iasl on big-endian machines, We already have a bunch of prebuilt blobs in the qemu repo for simliar reasons, we can do that with iasl output too. possible complexity of having to regenerate tables on a vm reboot, Why tables should be regenerated at reboot? I remember hotplug being mentioned in the call. Hmm? Which hotplugged component needs acpi table updates to work properly? And what is the point of hotplugging if you must reboot the guest anyway to get the acpi updates needed? Details please. Also mentioned in the call: architectural reasons, which I understand as real hardware works that way. Correct. But qemu's virtual hardware is configurable in more ways than real hardware, so we have different needs. For example: pci slots can or can't be hotpluggable. On real hardware this is fixed. IIRC this is one of the reasons why we have to patch acpi tables. overall sloppiness of doing it in QEMU. /me gets the feeling that this is the *main* reason, given that the other ones don't look very convincing to me. Raised that QOM interface should be sufficient. Agree on this one. Ideally the acpi table generation code should be able to gather all information it needs from the qom tree, so it can be a standalone C file instead of being scattered over all qemu. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. Certainly an option, but that is a long-term project. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Also simliar to the coreboot idea. Also in the call: The idea of having some library for acpi table generation provided by qemu which the firmware can use. Has license compatibility issues. Also difficult due to the fact that there is no libc in firmware, so such a library would need firmware-specific abstraction layers even for simple stuff such as memory allocation. Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. Good. I think having qemu generate the tables is also quite useful for evaluating the move to coreboot: (1) make qemu generate the acpi tables. (2a) make seabios use the qemu-generated tables. (2b) make ovmf use the qemu-generated tables. (2c) make coreboot use the qemu-generated tables. Now we can look where we stand when using coreboot+seabios or coreboot+tianocore compared to bare seabios / bare ovmf. I expect there are quite a few things to fix until the coreboot+seabios combo runs without regressions compared to bare seabios. But maybe not when qemu provides the acpi tables to coreboot. In case the coreboot testdrive works out well we can continue with: (3) use coreboot+seabios by default. (4) move acpi table generation from qemu to coreboot. cheers, Gerd ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, May 29, 2013 at 10:49:27AM +0200, Gerd Hoffmann wrote:
On 05/29/13 01:53, Kevin O'Connor wrote:
On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote:
Juan is not available now, and Anthony asked for
agenda to be sent early.
So here comes:
Agenda for the meeting Tue, May 28:
- Generating acpi tables
I didn't see any meeting notes, but I thought it would be worthwhile
to summarize the call. This is from memory so correct me if I got
anything wrong.
Anthony believes that the generation of ACPI tables is the task of the
firmware. Reasons cited include security implications of running more
code in qemu vs the guest context,
I fail to see the security issues here. It's not like the apci table
generation code operates on untrusted input from the guest ...
complexities in running iasl on
big-endian machines,
We already have a bunch of prebuilt blobs in the qemu repo for simliar
reasons, we can do that with iasl output too.
possible complexity of having to regenerate
tables on a vm reboot,
Why tables should be regenerated at reboot? I remember hotplug being
mentioned in the call. Hmm? Which hotplugged component needs acpi
table updates to work properly? And what is the point of hotplugging if
you must reboot the guest anyway to get the acpi updates needed?
Details please.
I think it's a mistake. I sent a mail explaining this part.
Also mentioned in the call: architectural reasons, which I understand
as real hardware works that way. Correct.
Not exactly. Real hardware is very likely to have
most of the tables pre-generated in ROM, load
them and tweak them in the minor way.
That's exactly what patches I sent do.
But qemu's virtual
hardware is configurable in more ways than real hardware, so we have
different needs. For example: pci slots can or can't be hotpluggable.
On real hardware this is fixed. IIRC this is one of the reasons why we
have to patch acpi tables.
overall sloppiness of doing it in QEMU.
/me gets the feeling that this is the *main* reason, given that the
other ones don't look very convincing to me.
Raised
that QOM interface should be sufficient.
Agree on this one. Ideally the acpi table generation code should be
able to gather all information it needs from the qom tree, so it can be
a standalone C file instead of being scattered over all qemu.
Did you look at the patchset I posted?
Generation is in a standalone C file there.
However, if you mean we should do things like
if (Device_id == foobar) {
}
in once central place, I disagree.
I think that's nasty, adding devices would
mean touching this central registry.
There were discussions on potentially introducing a middle component
to generate the tables. Coreboot was raised as a possibility, and
David thought it would be okay to use coreboot for both OVMF and
SeaBIOS.
Certainly an option, but that is a long-term project.
The possibility was also raised of a rom that lives in the
qemu repo, is run in the guest, and generates the tables (which is
similar to the hvmloader approach that Xen uses).
Also simliar to the coreboot idea.
Also in the call: The idea of having some library for acpi table
generation provided by qemu which the firmware can use. Has license
compatibility issues. Also difficult due to the fact that there is no
libc in firmware, so such a library would need firmware-specific
abstraction layers even for simple stuff such as memory allocation.
Anthony requested that patches be made that generate the ACPI tables
in QEMU for the upcoming hotplug work, so that they could be evaluated
to see if they truly do need to live in QEMU or if the code could live
in the firmware.
Good. I think having qemu generate the tables is also quite useful for
evaluating the move to coreboot:
(1) make qemu generate the acpi tables.
(2a) make seabios use the qemu-generated tables.
(2b) make ovmf use the qemu-generated tables.
(2c) make coreboot use the qemu-generated tables.
Now we can look where we stand when using coreboot+seabios or
coreboot+tianocore compared to bare seabios / bare ovmf. I expect there
are quite a few things to fix until the coreboot+seabios combo runs
without regressions compared to bare seabios. But maybe not when qemu
provides the acpi tables to coreboot.
In case the coreboot testdrive works out well we can continue with:
(3) use coreboot+seabios by default.
(4) move acpi table generation from qemu to coreboot.
cheers,
Gerd
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Re: [SeaBIOS] KVM call agenda for 2013-05-28
Hi,
possible complexity of having to regenerate
tables on a vm reboot,
Why tables should be regenerated at reboot? I remember hotplug being
mentioned in the call. Hmm? Which hotplugged component needs acpi
table updates to work properly? And what is the point of hotplugging if
you must reboot the guest anyway to get the acpi updates needed?
Details please.
I think it's a mistake. I sent a mail explaining this part.
Saw it meanwhile.
Also mentioned in the call: architectural reasons, which I understand
as real hardware works that way. Correct.
Not exactly. Real hardware is very likely to have
most of the tables pre-generated in ROM, load
them and tweak them in the minor way.
From a quick look it seems coreboot has a static (iasl-compiled) dsdt
and generates everything else.
http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/mainboard/emulation/qemu-x86/acpi_tables.c
Agree on this one. Ideally the acpi table generation code should be
able to gather all information it needs from the qom tree, so it can be
a standalone C file instead of being scattered over all qemu.
Did you look at the patchset I posted?
Very briefly only.
Generation is in a standalone C file there.
Good.
However, if you mean we should do things like
if (Device_id == foobar) {
}
in once central place, I disagree.
I think that's nasty, adding devices would
mean touching this central registry.
No, I mean more lookup PIIX4_PM object + check disable_s3 property
instead of having code for it in hw/acpi/piix4.c or using global variables.
cheers,
Gerd
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Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, May 29, 2013 at 11:42:34AM +0200, Gerd Hoffmann wrote:
Hi,
possible complexity of having to regenerate
tables on a vm reboot,
Why tables should be regenerated at reboot? I remember hotplug being
mentioned in the call. Hmm? Which hotplugged component needs acpi
table updates to work properly? And what is the point of hotplugging if
you must reboot the guest anyway to get the acpi updates needed?
Details please.
I think it's a mistake. I sent a mail explaining this part.
Saw it meanwhile.
Also mentioned in the call: architectural reasons, which I understand
as real hardware works that way. Correct.
Not exactly. Real hardware is very likely to have
most of the tables pre-generated in ROM, load
them and tweak them in the minor way.
From a quick look it seems coreboot has a static (iasl-compiled) dsdt
and generates everything else.
http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/mainboard/emulation/qemu-x86/acpi_tables.c
Agree on this one. Ideally the acpi table generation code should be
able to gather all information it needs from the qom tree, so it can be
a standalone C file instead of being scattered over all qemu.
Did you look at the patchset I posted?
Very briefly only.
Generation is in a standalone C file there.
Good.
However, if you mean we should do things like
if (Device_id == foobar) {
}
in once central place, I disagree.
I think that's nasty, adding devices would
mean touching this central registry.
No, I mean more lookup PIIX4_PM object + check disable_s3 property
instead of having code for it in hw/acpi/piix4.c or using global variables.
cheers,
Gerd
So that would make code PIIX specific.
Instead I'm passing in guest_info structure to each object
and that describes itself, e.g. sets disable_s3.
--
MST
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Re: [SeaBIOS] KVM call agenda for 2013-05-28
Gerd Hoffmann kra...@redhat.com writes: On 05/29/13 01:53, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, I fail to see the security issues here. It's not like the apci table generation code operates on untrusted input from the guest ... But possibly untrusted input from a malicious user. You can imagine something like a IaaS provider that let's a user input arbitrary values for memory, number of nics, etc. It's a stretch of an example, I agree, but the general principle I think is sound: we should push as much work as possible to the least privileged part of the stack. In this case, firmware has much less privileges than QEMU. complexities in running iasl on big-endian machines, We already have a bunch of prebuilt blobs in the qemu repo for simliar reasons, we can do that with iasl output too. possible complexity of having to regenerate tables on a vm reboot, Why tables should be regenerated at reboot? I remember hotplug being mentioned in the call. Hmm? Which hotplugged component needs acpi table updates to work properly? And what is the point of hotplugging if you must reboot the guest anyway to get the acpi updates needed? Details please. See my response to Michael. Also mentioned in the call: architectural reasons, which I understand as real hardware works that way. Correct. But qemu's virtual hardware is configurable in more ways than real hardware, so we have different needs. For example: pci slots can or can't be hotpluggable. On real hardware this is fixed. IIRC this is one of the reasons why we have to patch acpi tables. It's not really fixed. Hardware supports PCI expansion chassises. Multi-node NUMA systems also affect the ACPI tables. overall sloppiness of doing it in QEMU. /me gets the feeling that this is the *main* reason, given that the other ones don't look very convincing to me. Raised that QOM interface should be sufficient. Agree on this one. Ideally the acpi table generation code should be able to gather all information it needs from the qom tree, so it can be a standalone C file instead of being scattered over all qemu. Ack. So my basic argument is why not expose the QOM interfaces to firmware and move the generation code there? Seems like it would be more or less a copy/paste once we had a proper implementation in QEMU. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. Certainly an option, but that is a long-term project. Out of curiousity, are there other benefits to using coreboot as a core firmware in QEMU? Is there a payload we would ever plausibly use besides OVMF and SeaBIOS? Regards, Anthony Liguori ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, May 29, 2013 at 11:18:03AM -0500, Anthony Liguori wrote: Gerd Hoffmann kra...@redhat.com writes: On 05/29/13 01:53, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, I fail to see the security issues here. It's not like the apci table generation code operates on untrusted input from the guest ... But possibly untrusted input from a malicious user. You can imagine something like a IaaS provider that let's a user input arbitrary values for memory, number of nics, etc. It's a stretch of an example, I agree, but the general principle I think is sound: we should push as much work as possible to the least privileged part of the stack. In this case, firmware has much less privileges than QEMU. It's a big stretch. We have to draw the line somewhere, and I think when *all* firmware people tell us that QEMU is a pain to work with and should just supply ACPI table to BIOS, that line has been crossed. complexities in running iasl on big-endian machines, We already have a bunch of prebuilt blobs in the qemu repo for simliar reasons, we can do that with iasl output too. possible complexity of having to regenerate tables on a vm reboot, Why tables should be regenerated at reboot? I remember hotplug being mentioned in the call. Hmm? Which hotplugged component needs acpi table updates to work properly? And what is the point of hotplugging if you must reboot the guest anyway to get the acpi updates needed? Details please. See my response to Michael. Also mentioned in the call: architectural reasons, which I understand as real hardware works that way. Correct. But qemu's virtual hardware is configurable in more ways than real hardware, so we have different needs. For example: pci slots can or can't be hotpluggable. On real hardware this is fixed. IIRC this is one of the reasons why we have to patch acpi tables. It's not really fixed. Hardware supports PCI expansion chassises. These normally aren't reported in ACPI, so no hotplug, or only native hotplug. Multi-node NUMA systems also affect the ACPI tables. In a very minor way. overall sloppiness of doing it in QEMU. /me gets the feeling that this is the *main* reason, given that the other ones don't look very convincing to me. Raised that QOM interface should be sufficient. Agree on this one. Ideally the acpi table generation code should be able to gather all information it needs from the qom tree, so it can be a standalone C file instead of being scattered over all qemu. Ack. So my basic argument is why not expose the QOM interfaces to firmware and move the generation code there? Seems like it would be more or less a copy/paste once we had a proper implementation in QEMU. Because that's just insanely rick interface we have no chance to keep stable across versions. Because it's a ton of QEMU specific firmware. Because firmware devs don't want to maintain the ACPI that *is* there either. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. Certainly an option, but that is a long-term project. Out of curiousity, are there other benefits to using coreboot as a core firmware in QEMU? Is there a payload we would ever plausibly use besides OVMF and SeaBIOS? Regards, Anthony Liguori The easier it is to switch firmware the better. Gives us choice, we switched firmware several times, we will do it again. If firmware only has a simple loader for QEMU specific stuff and is mostly generic, then it's easy. If there's a lot of code for walking QOM, etc - it's very painful. -- MST ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
Anthony Liguori anth...@codemonkey.ws writes: Gerd Hoffmann kra...@redhat.com writes: On 05/29/13 01:53, Kevin O'Connor wrote: On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, I fail to see the security issues here. It's not like the apci table generation code operates on untrusted input from the guest ... But possibly untrusted input from a malicious user. You can imagine something like a IaaS provider that let's a user input arbitrary values for memory, number of nics, etc. It's a stretch of an example, I agree, but the general principle I think is sound: we should push as much work as possible to the least privileged part of the stack. In this case, firmware has much less privileges than QEMU. Firmware runs in a primitive, unforgiving environment, and should do as little as humanly possible. For an instructive example of deviating from that rule, check out UEFI. [...] ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, May 29, 2013 at 07:28:05PM +0300, Michael S. Tsirkin wrote: Because that's just insanely rick interface s/rick/rich/. Sorry about the typo. ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Wed, May 29, 2013 at 11:18:03AM -0500, Anthony Liguori wrote: Gerd Hoffmann kra...@redhat.com writes: On 05/29/13 01:53, Kevin O'Connor wrote: Raised that QOM interface should be sufficient. Agree on this one. Ideally the acpi table generation code should be able to gather all information it needs from the qom tree, so it can be a standalone C file instead of being scattered over all qemu. Ack. So my basic argument is why not expose the QOM interfaces to firmware and move the generation code there? I remain doubtful that QOM has all the info needed to generate the BIOS tables. Does QOM describe how the 5th pci device uses global interrupt 11 when using global interrupts, legacy interrupt 5 when not using global interrupts, and that the legacy interrupt can be changed by writing to the 0x60 address of the 1st pci device's config space? Does QOM state that the machine supports S3 sleep mode? Does QOM indicate that an IPMI device supports the 3rd version of the IPMI device specification? I don't see how exporting QOM to the firmware will help. I predict we would continue to see most of the BIOS tables hardcoded in the firmware and that all but the most minor changes to those tables would require synchronizing code patches to both QEMU and the firmware. I also suspect we would end up adding fields to QOM that only the BIOS tables cared about, and that ever increasing code would be needed in both QEMU and the firmware to juggle to/from QOM so that the BIOS tables could be created. -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
Re: [SeaBIOS] KVM call agenda for 2013-05-28
On Thu, May 23, 2013 at 03:41:32PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, May 28: - Generating acpi tables I didn't see any meeting notes, but I thought it would be worthwhile to summarize the call. This is from memory so correct me if I got anything wrong. Anthony believes that the generation of ACPI tables is the task of the firmware. Reasons cited include security implications of running more code in qemu vs the guest context, complexities in running iasl on big-endian machines, possible complexity of having to regenerate tables on a vm reboot, overall sloppiness of doing it in QEMU. Raised that QOM interface should be sufficient. Kevin believes that the bios table code should be moved up into QEMU. Reasons cited include the churn rate in SeaBIOS for this QEMU feature (15-20% of all SeaBIOS commits since integrating with QEMU have been for bios tables; 20% of SeaBIOS commits in last year), complexity of trying to pass all the content needed to generate the tables (eg, device details, power tree, irq routing), complexity of scheduling changes across different repos and synchronizing their rollout, complexity of implemeting the code in both OVMF and SeaBIOS. Kevin wasn't aware of a requirement to regenerate acpi tables on a vm reboot. There were discussions on potentially introducing a middle component to generate the tables. Coreboot was raised as a possibility, and David thought it would be okay to use coreboot for both OVMF and SeaBIOS. The possibility was also raised of a rom that lives in the qemu repo, is run in the guest, and generates the tables (which is similar to the hvmloader approach that Xen uses). Anthony requested that patches be made that generate the ACPI tables in QEMU for the upcoming hotplug work, so that they could be evaluated to see if they truly do need to live in QEMU or if the code could live in the firmware. There were no objections. -Kevin ___ SeaBIOS mailing list SeaBIOS@seabios.org http://www.seabios.org/mailman/listinfo/seabios
