Re: [Qemu-devel] KVM/QEMU on Raspberry Pi 3

[Ard Biesheuvel]

On 2 February 2017 at 15:50, Laszlo Ersek <address@hidden> wrote:
> Adding Ard, just in case...
>
> I have one (half-)comment re: GICv3:
>
> On 02/02/17 15:44, Pekka Enberg wrote:
>> Hi,
>>
>> Has anyone been able to successfully run QEMU/KVM under Raspberry Pi 3?
>>
>> I have installed 64-bit Fedora 24 by Gerd Hoffmann on the hardware:
>>
>>   https://www.kraxel.org/blog/2016/04/fedora-on-raspberry-pi-updates/
>>
>> and built a VM image using virt-builder:
>>
>>   virt-builder --root-password password:root --arch aarch64 fedora-24
>>
>> I also built the latest UEFI for QEMU from sources:
>>
>>   https://wiki.linaro.org/LEG/UEFIforQEMU
>>
>> and updated to QEMU 2.8.0 from rawhide:
>>
>>   address@hidden ~]# qemu-system-aarch64 -version
>>   QEMU emulator version 2.8.0(qemu-2.8.0-1.fc26)
>>   Copyright (c) 2003-2016 Fabrice Bellard and the QEMU Project developers
>>
>> The VM image should be fine because I’m able to boot to it under CPU
>> emulation:
>>
>> qemu-system-aarch64 \
>>           -nographic \
>>           -M virt \
>>           -cpu cortex-a57 \
>>           -smp 1 \
>>           -m 512 \
>>           -bios QEMU_EFI.fd \
>>           -device virtio-blk-device,drive=image -drive
>> if=none,id=image,file=fedora-24.img \
>>           -netdev bridge,id=hn0,br=virbr0 -device
>> virtio-net-pci,netdev=hn0,romfile= \
>>           -device virtio-rng-pci
>>
[..]
>> I also tried to enable GIC v3 by adding the “-machine gic-version=3”
>> command one option but the UEFI firmware doesn’t like that:
>>
>> Found GIC v3 (re)distributor @ 0x8000000 (0x80A0000)
>>
>>
>> Synchronous Exception at 0x000000005BD5B820
>> PC 0x00005BD5B820 (0x00005BD58000+0x00003820) [ 0] ArmGicDxe.dll
>> PC 0x00005BD5BC38 (0x00005BD58000+0x00003C38) [ 0] ArmGicDxe.dll
>> PC 0x00005BD593B0 (0x00005BD58000+0x000013B0) [ 0] ArmGicDxe.dll
>> PC 0x00005BD590A0 (0x00005BD58000+0x000010A0) [ 0] ArmGicDxe.dll
>> PC 0x00005EF1ADF4 (0x00005EF14000+0x00006DF4) [ 1] DxeCore.dll
>> PC 0x00005EF32B0C (0x00005EF14000+0x0001EB0C) [ 1] DxeCore.dll
>> PC 0x00005EF165E4 (0x00005EF14000+0x000025E4) [ 1] DxeCore.dll
>> PC 0x00005EF15828 (0x00005EF14000+0x00001828) [ 1] DxeCore.dll
>> PC 0x00005EF15024 (0x00005EF14000+0x00001024) [ 1] DxeCore.dll
>>
>> [ 0]
>> /home/penberg/raspberrypi/uefi/edk2/Build/ArmVirtQemu-AARCH64/DEBUG_GCC5/AARCH64/ArmPkg/Drivers/ArmGic/ArmGicDxe/DEBUG/ArmGicDxe.dll
>>
>> [ 1]
>> /home/penberg/raspberrypi/uefi/edk2/Build/ArmVirtQemu-AARCH64/DEBUG_GCC5/AARCH64/MdeModulePkg/Core/Dxe/DxeMain/DEBUG/DxeCore.dll
>>
>>
>>   X0 0x0000000000000036   X1 0x0000000000000004   X2 0x0000000000000036
>>   X3 0x0000000000000000
>>   X4 0x0000000000000001   X5 0x0000000000000000   X6 0x0A01191513061C12
>>   X7 0x121C06131519010A
>>   X8 0x00000000041ECB83   X9 0x0000000700000000  X10 0x0000000058B60000
>>  X11 0x0000000000000004
>>  X12 0x0000000000000001  X13 0x0000000000000008  X14 0x0000000000000000
>>  X15 0x0000000000000000
>>  X16 0x000000005EF13DF0  X17 0x0000000000000000  X18 0x0000000000000000
>>  X19 0x000000004007C268
>>  X20 0x0000000000000000  X21 0x0000000000000000  X22 0x0000000000000000
>>  X23 0x0000000000000000
>>  X24 0x0000000000000000  X25 0x0000000000000000  X26 0x0000000000000000
>>  X27 0x0000000000000000
>>  X28 0x0000000000000000   FP 0x000000005EF13D20   LR 0x000000005BD5BC38
>>
>>   V0 0xAFAFAFAFAFAFAFAF AFAFAFAFAFAFAFAF   V1 0x0000000000000000
>> 0000000000000000
>>   V2 0x0000000000000000 0000000000000000   V3 0x0000000000000000
>> 0000000000000000
>>   V4 0x0000000000000000 0000000000000000   V5 0x0000000000000000
>> 0000000000000000
>>   V6 0x0000000000000000 0000000000000000   V7 0x0000000000000000
>> 0000000000000000
>>   V8 0x0000000000000000 0000000000000000   V9 0x0000000000000000
>> 0000000000000000
>>  V10 0x0000000000000000 0000000000000000  V11 0x0000000000000000
>> 0000000000000000
>>  V12 0x0000000000000000 0000000000000000  V13 0x0000000000000000
>> 0000000000000000
>>  V14 0x0000000000000000 0000000000000000  V15 0x0000000000000000
>> 0000000000000000
>>  V16 0x0000000000000000 0000000000000000  V17 0x0000000000000000
>> 0000000000000000
>>  V18 0x0000000000000000 0000000000000000  V19 0x0000000000000000
>> 0000000000000000
>>  V20 0x0000000000000000 0000000000000000  V21 0x0000000000000000
>> 0000000000000000
>>  V22 0x0000000000000000 0000000000000000  V23 0x0000000000000000
>> 0000000000000000
>>  V24 0x0000000000000000 0000000000000000  V25 0x0000000000000000
>> 0000000000000000
>>  V26 0x0000000000000000 0000000000000000  V27 0x0000000000000000
>> 0000000000000000
>>  V28 0x0000000000000000 0000000000000000  V29 0x0000000000000000
>> 0000000000000000
>>  V30 0x0000000000000000 0000000000000000  V31 0x0000000000000000
>> 0000000000000000
>>
>>   SP 0x000000005EF13D20  ELR 0x000000005BD5B820  SPSR 0x80000205  FPSR
>> 0x00000000
>>  ESR 0x02000000          FAR 0x1DE7EC7EDBADC0DE
>>


$ git grep -C5 -ni 0x1DE7EC7EDBADC0DE
arch/arm64/kvm/sys_regs.h-105-static inline void reset_unknown(struct
kvm_vcpu *vcpu,
arch/arm64/kvm/sys_regs.h-106-                           const struct
sys_reg_desc *r)
arch/arm64/kvm/sys_regs.h-107-{
arch/arm64/kvm/sys_regs.h-108-  BUG_ON(!r->reg);
arch/arm64/kvm/sys_regs.h-109-  BUG_ON(r->reg >= NR_SYS_REGS);
arch/arm64/kvm/sys_regs.h:110:  vcpu_sys_reg(vcpu, r->reg) =
0x1de7ec7edbadc0deULL;
arch/arm64/kvm/sys_regs.h-111-}
arch/arm64/kvm/sys_regs.h-112-

In other words (or rather, in words), KVM is triggering this exception
in the guest deliberately, which I suspect has something to do with
the lack of a GIC? Are you using these patches Peter mentions?

-- 
Ard.