Re: [PATCH v3 2/3] i386: Explicitly ignore unsupported BUS_MCEERR_AO MCE on AMD guest

[Gupta, Pankaj]

On 9/6/2023 10:53 PM, John Allen wrote:
> From: William Roche <william.roche@oracle.com>
>
> AMD guests can't currently deal with BUS_MCEERR_AO MCE injection
> as it panics the VM kernel. We filter this event and provide a
> warning message.
>
> Signed-off-by: William Roche <william.roche@oracle.com>
> ---
> v3:
>    - New patch
> ---
>   target/i386/kvm/kvm.c | 13 ++++++++++---
>   1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index 5fce74aac5..4d42d3ed4c 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -604,6 +604,10 @@ static void kvm_mce_inject(X86CPU *cpu, hwaddr paddr, int 
> code)
>               mcg_status |= MCG_STATUS_RIPV;
>           }
>       } else {
> +        if (code == BUS_MCEERR_AO) {
> +            /* XXX we don't support BUS_MCEERR_AO injection on AMD yet */
> +            return;
> +        }
>           mcg_status |= MCG_STATUS_EIPV | MCG_STATUS_RIPV;
>       }
>   
> @@ -655,7 +659,9 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
>           if (ram_addr != RAM_ADDR_INVALID &&
>               kvm_physical_memory_addr_from_host(c->kvm_state, addr, &paddr)) {
>               kvm_hwpoison_page_add(ram_addr);
> -            kvm_mce_inject(cpu, paddr, code);
> +            if (!IS_AMD_CPU(env) || code != BUS_MCEERR_AO) {

Isn't the 'optional' case we already handle inside kvm_mce_inject()?
So this check seems repetitive to me.

Thanks,
Pankaj
> +                kvm_mce_inject(cpu, paddr, code);
> +            }
>   
>               /*
>                * Use different logging severity based on error type.
> @@ -668,8 +674,9 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void 
> *addr)
>                       addr, paddr, "BUS_MCEERR_AR");
>               } else {
>                    warn_report("Guest MCE Memory Error at QEMU addr %p and "
> -                     "GUEST addr 0x%" HWADDR_PRIx " of type %s injected",
> -                     addr, paddr, "BUS_MCEERR_AO");
> +                     "GUEST addr 0x%" HWADDR_PRIx " of type %s %s",
> +                     addr, paddr, "BUS_MCEERR_AO",
> +                     IS_AMD_CPU(env) ? "ignored on AMD guest" : "injected");
>               }
>   
>               return;