Re: [Qemu-devel] [PATCH for-2.7] target-i386: kvm: Report kvm_pv_unhalt as unsupported w/o kernel_irqchip

[Eduardo Habkost <ehabkost@redhat.com>]

Sorry, forgot the for-2.7 tag in the Subject. This is a bug fix I
would like to get into QEMU 2.7.

On Fri, Aug 12, 2016 at 03:14:32PM -0300, Eduardo Habkost wrote:
> The kvm_pv_unhalt feature doesn't work if kernel_irqchip is
> disabled, so we need to report it as unsupported.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
>  target-i386/kvm.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 0b2016a..d1a25c5 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -329,6 +329,13 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t function,
>           */
>          cpuid_1_edx = kvm_arch_get_supported_cpuid(s, 1, 0, R_EDX);
>          ret |= cpuid_1_edx & CPUID_EXT2_AMD_ALIASES;
> +    } else if (function == KVM_CPUID_FEATURES && reg == R_EAX) {
> +        /* kvm_pv_unhalt is reported by GET_SUPPORTED_CPUID, but it can't
> +         * be enabled without the in-kernel irqchip
> +         */
> +        if (!kvm_irqchip_in_kernel()) {
> +            ret &= ~(1U << KVM_FEATURE_PV_UNHALT);
> +        }
>      }
>  
>      /* fallback for older kernels */
> -- 
> 2.7.4
> 

-- 
Eduardo