Re: [kvm-unit-tests PATCH v3] runtime: Allow to specify properties for accelerator

[Gavin Shan <gshan@redhat.com>]

Hi Drew,

On 6/20/23 19:06, Andrew Jones wrote:
> On Tue, Jun 20, 2023 at 02:13:22PM +1000, Gavin Shan wrote:
>> On 6/19/23 18:45, Andrew Jones wrote:
>>> On Thu, Jun 15, 2023 at 04:21:48PM +1000, Gavin Shan wrote:
>>>> There are extra properties for accelerators to enable the specific
>>>> features. For example, the dirty ring for KVM accelerator can be
>>>> enabled by "-accel kvm,dirty-ring-size=65536". Unfortuntely, the
>>>> extra properties for the accelerators aren't supported. It makes
>>>> it's impossible to test the combination of KVM and dirty ring
>>>> as the following error message indicates.
>>>>
>>>>     # cd /home/gavin/sandbox/kvm-unit-tests/tests
>>>>     # QEMU=/home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>>>>       ACCEL=kvm,dirty-ring-size=65536 ./its-migration
>>>>        :
>>>>     BUILD_HEAD=2fffb37e
>>>>     timeout -k 1s --foreground 90s /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \
>>>>     -nodefaults -machine virt -accel kvm,dirty-ring-size=65536 -cpu cortex-a57             \
>>>>     -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd   \
>>>>     -device pci-testdev -display none -serial stdio -kernel _NO_FILE_4Uhere_ -smp 160      \
>>>>     -machine gic-version=3 -append its-pending-migration # -initrd /tmp/tmp.gfDLa1EtWk
>>>>     qemu-system-aarch64: kvm_init_vcpu: kvm_arch_init_vcpu failed (0): Invalid argument
>>>>
>>>> Allow to specify extra properties for accelerators. With this, the
>>>> "its-migration" can be tested for the combination of KVM and dirty
>>>> ring.
>>>>
>>>> Signed-off-by: Gavin Shan <gshan@redhat.com>
>>>> ---
>>>> v3: Split $ACCEL to $ACCEL and $ACCEL_PROPS in get_qemu_accelerator()
>>>>       and don't print them as output, suggested by Drew.
>>>> ---
>>>>    arm/run               | 12 ++++--------
>>>>    powerpc/run           |  5 ++---
>>>>    s390x/run             |  5 ++---
>>>>    scripts/arch-run.bash | 21 +++++++++++++--------
>>>>    x86/run               |  5 ++---
>>>>    5 files changed, 23 insertions(+), 25 deletions(-)
>>>>
>>>> diff --git a/arm/run b/arm/run
>>>> index c6f25b8..d9ebe59 100755
>>>> --- a/arm/run
>>>> +++ b/arm/run
>>>> @@ -10,10 +10,8 @@ if [ -z "$KUT_STANDALONE" ]; then
>>>>    fi
>>>>    processor="$PROCESSOR"
>>>> -accel=$(get_qemu_accelerator) ||
>>>> -	exit $?
>>>> -
>>>> -if [ "$accel" = "kvm" ]; then
>>>> +get_qemu_accelerator || exit $?
>>>> +if [ "$ACCEL" = "kvm" ]; then
>>>>    	QEMU_ARCH=$HOST
>>>>    fi
>>>> @@ -23,11 +21,9 @@ qemu=$(search_qemu_binary) ||
>>>>    if [ "$QEMU" ] && [ -z "$ACCEL" ] &&
>>>>       [ "$HOST" = "aarch64" ] && [ "$ARCH" = "arm" ] &&
>>>>       [ "$(basename $QEMU)" = "qemu-system-arm" ]; then
>>>> -	accel=tcg
>>>> +	ACCEL="tcg"
>>>>    fi
>>>
>>> As I pointed out in the v2 review we can't just s/accel/ACCEL/ without
>>> other changes. Now ACCEL will also be set when the above condition
>>> is checked, making it useless. Please ensure the test case that commit
>>> c7d6c7f00e7c ("arm/run: Use TCG with qemu-system-arm on arm64 systems")
>>> fixed still works with your patch.
>>>
>>
>> Sorry that I missed your comments for v2. In order to make the test case
>> in c7d6c7f00e7c working, we just need to call set_qemu_accelerator() after
>> the chunk of code, like below. When $ACCEL is set to "tcg" by the conditional
>> code, it won't be changed in the following set_qemu_accelerator().
>>
>> Could you Please confirm if it looks good to you so that I can integrate
>> the changes to v4 and post it.
>>
>> arm/run
>> --------
>>
>> processor="$PROCESSOR"
>>
>> if [ "$QEMU" ] && [ -z "$ACCEL" ] &&
>>     [ "$HOST" = "aarch64" ] && [ "$ARCH" = "arm" ] &&
>>     [ "$(basename $QEMU)" = "qemu-system-arm" ]; then
>>          ACCEL="tcg"
>> fi
>>
>> set_qemu_accelerator || exit $?
>> if [ "$ACCEL" = "kvm" ]; then
>>          QEMU_ARCH=$HOST
>> fi
>>
> 
> Looks fine, but please give it a test run.
> 

Thanks, Drew. v4 has been posted for further review. Since I don't have a 'arm'
host around, I adjust $ARCH to "arm64" for a simulation and the test case included
in commit c7d6c7f00e7c should be working fine: We eventually have "tcg" instead of
"kvm" accelerator for the combination, which is expected by commit c7d6c7f00e7c

v4: https://lore.kernel.org/kvmarm/20230623035750.312679-1-gshan@redhat.com/T/#u

Thanks,
Gavin