On 25 July 2018 at 19:26, Andrew Jones <drjo...@redhat.com> wrote: > On Wed, Jul 25, 2018 at 06:22:17PM +0800, Hongbo Zhang wrote: >> On 25 July 2018 at 17:54, Andrew Jones <drjo...@redhat.com> wrote: >> > On Wed, Jul 25, 2018 at 01:30:52PM +0800, Hongbo Zhang wrote: >> >> For the Aarch64, there is one machine 'virt', it is primarily meant to >> >> run on KVM and execute virtualization workloads, but we need an >> >> environment as faithful as possible to physical hardware, for supporting >> >> firmware and OS development for pysical Aarch64 machines. >> >> >> >> This patch introduces new machine type 'Enterprise' with main features: >> >> - Based on 'virt' machine type. >> >> - Re-designed memory map. >> >> - EL2 and EL3 are enabled by default. >> >> - GIC version 3 by default. >> >> - AHCI controller attached to system bus, and then CDROM and hard disc >> >> can be added to it. >> >> - EHCI controller attached to system bus, with USB mouse and key board >> >> installed by default. >> >> - E1000E ethernet card on PCIE bus. >> >> - VGA display adaptor on PCIE bus. >> >> - Default CPU type cortex-a57, 4 cores, and 1G bytes memory. >> >> - No virtio functions enabled, since this is to emulate real hardware. >> > >> > In the last review it was pointed out that using virtio-pci should still >> > be "real" enough, so there's not much reason to avoid it. Well, unless >> > there's some concern as to what drivers are available in the firmware and >> > guest kernel. But that concern usually only applies to legacy firmwares >> > and kernels, and therefore shouldn't apply to AArch64. >> > >> In real physical arm hardware, *HCI are system memory mapped, not on PCIE. >> we need a QEMU platform like that. We need firmware developed on this >> QEMU platform can run on real hardware without change(or only a minor >> change) > > virtio-pci has nothing to do with *HCI. You're adding an E1000e to the > PCIe bus instead of a virtio-pci nic. Why? > No virtio devices are need on this platform, so no virtio-pci either, on the real Arm server hardware, a NIC is inserted into PCIE, and E1000E is a typical one.
>> Concern is not only available firmwares, but more emphasis is on new >> firmwares to be developed on this platform (target is developing >> firmware for hardware, but using qemu if hardware is not available >> temporarily), if virtio device used, then the newly developed firmware >> must include virtio front-end codes, but it isn't needed while run on >> real hardware at last. > > Right. The new firmwares and kernels would need to include virtio-pci nic > and scsi drivers. Is that a problem? Anyway, this is all the more reason > not to hard code peripherals. If a particular peripheral is a problem > for a given firmware, then simply don't add it to the command line, add a > different one. > Yes that is problem, for newly developed firmwares, extra efforts will be wasted on frontend codes (or glue-layer, whatever we call it), we want firmwares developed on this platform can run easily on real hardware, without such change. Requirement is: some Linaro members just want a qemu platform as true as possible with real hardware, there should be no problem with such requirement, problem is 'virt' machine cannot satisfy the requirement, so a new one is needed. >> >> >> - No paravirtualized fw_cfg device either. >> >> >> >> Arm Trusted Firmware and UEFI porting to this are done accordingly. >> >> >> > >> > How will UEFI get the ACPI tables from QEMU without fw-cfg? I didn't >> > see any sort of reserved ROM region in the patch for them. >> > >> UEFI gets ACPI and kernel from network or mass storage, just like the >> real hardware. > > Hmm. I thought for real hardware that the ACPI tables were built into > the firmware. So, assuming UEFI knows how to read ACPI tables from > some storage, then how do the QEMU generated ACPI tables get into that > storage? > I should say "mass storage and flash" There was fw_cfg in v1 patch, it is removed in v2. If no fw_cfg, just like real hardware, UEFI should include ACPI support for this SBSA platform, and UEFI/ACPI is load via -pflash, then the QEMU built-in ACPI isn't used. But there are side effects too, command 'qemu -bios uefi -kernel' won't work, I need extra time to evaluate this change. >> If we develop firmware depends on paravirtualized device like fw_cfg, >> then we canot run such firmware on real hardware. > > Yes, fw-cfg is paravirt, so it's obvious why you'd prefer it not be there, > but, where real hardware builds its hardware descriptions into its > platform-specific firmware, or uses some platform-specific means of > extracting a description from some platform-specific place, QEMU > machine models use fw-cfg. > > Thanks, > drew
