Re: [kvm-unit-tests PATCH v2 2/2] x86/run: Use separate "-accel" option to configure the accelerator

[Sean Christopherson <seanjc@google.com>]

On Tue, Sep 29, 2026, Xiaoyao Li wrote:
> When configuring accelerator via machine's "accel" property, it cannot
> pass additional ACCEL_PROPS. For example, it hits following error when
> configuring KVM with "notify-vmexit":
> 
>   # ACCEL="kvm,notify-vmexit=internal-error" ./x86-run x86/apic.c
>   #   qemu-system-x86_64: Property 'pc-i440fx-11.1-machine.notify-vmexit' not found
> 
> Switch to use separate "-accel" option to configure the accelerator.

FYI, this breaks the intel_iommu test when running with ACCEL="kvm,kernel-irqchip=on"
because that's a split-only test:

  qemu_params = -M q35,kernel-irqchip=split -device intel-iommu,intremap=on,eim=off -device edu

and QEMU doesn't munge things together:

  qemu: -device intel-iommu,intremap=on,eim=off: Interrupt Remapping cannot work with kernel-irqchip=on, please use 'split|off'.

Given that I'm pretty sure I'm literally the only person the world that runs KUT
with ACCEL="kvm,kernel-irqchip=on", I'm going to apply this as-is.  I can filter
out the failures very easily, and unlike the CET/LAM issue, this doesn't cause
problems for ACCEL="kvm,kernel-irqchip=split", i.e. there's no loss in coverage.

If this impacts someone else, or someone really wants to figure out how to splice
all of this together, I'm happy to revisit things.  For now, I just want to
unblock the notify-vmexit stuff.

> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
>  x86/run | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/x86/run b/x86/run
> index dd38f14c871f..a68d469dd1b8 100755
> --- a/x86/run
> +++ b/x86/run
> @@ -43,7 +43,7 @@ fi
>  pit="-global kvm-pit.lost_tick_policy=discard"
>  
>  command="${qemu} --no-reboot -nodefaults $pit $pc_testdev -display none -serial stdio $pci_testdev"
> -command+=" -machine accel=$ACCEL$ACCEL_PROPS"
> +command+=" -accel $ACCEL$ACCEL_PROPS"
>  if [ "${CONFIG_EFI}" != y ]; then
>  	command+=" -kernel"
>  fi
> -- 
> 2.53.0
> 
>