* Jan Kiszka <[email protected]> [2017-09-01 18:32:54 +0000]: > On 2017-09-01 20:08, Gustavo Lima Chaves wrote: > > Hi. > > > > I'm already experimenting with this issue, in the way of trying to get > > Zephyr + xAPIC good to go, besides x2APIC, but here goes the doubt in > > order to confirm it. > > > > The function in the subject, which offloads work to apic_mmio_access() > > and then to x86_mmio_parse(), has this last one parse the instruction > > doing APIC mem. region access in order to intercept the access and > > either put or take a value to/from that memory into a register. > > > > Some MOV variants are covered there, but we are *very far* from having > > any reasonable coverage in that list. For instance, all the parsing > > code assumes the from/to places (other than the APIC mem. region) are > > always registers—at least that's what I understand now. What about > > memory regions and immediate values? > > > > Zephyr generates code using different MOVs to access the APIC mem. > > region and I'm filling up that list + parsing code with more info > > trying to capture that. > > > > Am I wrong in any point? > > Jailhouse implements support for emulating only very few instructions, > because this can easily explode the code size. Basically, we just > support what Linux needs and define that all other guests should > restrict themselves to those instructions. That's also why there are > MMIO accessors in the libinmate. > > Now one may argue about adding one or two more simple mov instructions > to the emulator if it really helps, we did that before, but I do not > want to expand beyond that.
Ok, that's the case anyway, some number around that. > > The proper answer to that issue would be hardware support for > instruction parsing, just like other archs have. It's really lame that > MMIO interception requires so much effort in software. I agree, such pain to parse that as well. Now for something different: why allowing only fixed and NMI delivery modes for APIC on guests? Is ExtINT detrimental in any way? That's what Zephyr uses... > > Jan > > -- > Siemens AG, Corporate Technology, CT RDA ITP SES-DE > Corporate Competence Center Embedded Linux -- Gustavo Lima Chaves Intel - Open Source Technology Center -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
