Re: [Qemu-devel] [PATCH v3 00/34] target/arm: Implement ARMv8.1-VHE

[Richard Henderson]

On 8/5/19 6:02 AM, Alex Bennée wrote:
> 
> Richard Henderson <address@hidden> writes:
> 
>> About half of this patch set is cleanup of the qemu tlb handling
>> leading up to the actual implementation of VHE, and the biggest
>> piece of that: The EL2&0 translation regime.
>>
>> Changes since v2:
>>   * arm_mmu_idx was incomplete; test TGE+E2H not just E2H.
>>   * arm_sctlr was incomplete; now uses arm_mmu_idx to avoid
>>     duplication of tests.
>>   * Update aa64_zva_access and ctr_el0_access for EL2.
>>
>> Changes since v1:
>>   * Merge feedback from AJB.
>>   * Split out 7 renaming patches from "Reorganize ARMMMUIdx".
>>   * Alex's MIDR patch keeps the nested KVM from spitting warnings.
>>
>> I have tested
>>
>>   qemu-system-aarch64 -accel kvm -cpu host -M virt,gic-version-host \
>>     -m 512 -bios /usr/share/edk2/aarch64/QEMU_EFI.fd -nographic
> 
> So testing with a host doing:
> 
>   ./aarch64-softmmu/qemu-system-aarch64 -machine type=virt,virtualization=on 
> -cpu cortex-a57 -serial mon:stdio -nic 
> user,model=virtio-net-pci,hostfwd=tcp::2222-:22 -device virtio-scsi-pci 
> -drive 
> file=/dev/zvol/hackpool-0/debian-buster-arm64,id=hd0,index=0,if=none,format=raw,discard=on
>  -device scsi-hd,drive=hd0 -kernel 
> ../linux.git/builds/arm64/arch/arm64/boot/Image -append "console=ttyAMA0 
> root=/dev/sda2" -display none -m 4096 -smp 8
> 
> And a guest doing:
> 
>   ./aarch64-softmmu/qemu-system-aarch64 -machine type=virt -cpu host
>   -serial mon:stdio -nic user,model=virtio-net-pci -device
>   virtio-scsi-pci -kernel /boot/vmlinuz-4.19.0-5-arm64 -append 
> "console=ttyAMA0 panic=-1" -display none -m 256 -smp 4 --no-reboot
>   --enable-kvm
> 
> I triggered:
> 
>   
> ERROR:/home/alex.bennee/lsrc/qemu.git/target/arm/helper.c:3436:update_lpae_el1_asid:
>  code should not be reached
> fish: “./aarch64-softmmu/qemu-system-a…” terminated by signal SIGABRT (Abort)

Whoops.  Rebase error while changing the signature of this function.
Thanks for re-testing the case where VHE isn't present.  :-P

> With -cpu max on the host it hangs the whole thing. I'm going to
> continue to experiment with explicit GIC versions.

Hangs the host?  Are you sure that the guest isn't just slow?
That's why I changed my testing to boot a debug edk2, which
outputs stuff much sooner than the kernel does.

Although I have no idea why the guest should be extra slow.
It does seem like it ought to be booting at the same speed as
the host.  I see tlb flushes as quite high in the profile,
and wonder if I'm doing too many of them.


r~