Re: [PATCH v2 6/9] target/i386: Do not broadcast injected MCEs for Hygon

On Mon, Aug 10, 2026 at 04:29:53PM +0800, Tina Zhang wrote:
> Date: Mon, 10 Aug 2026 16:29:53 +0800
> From: Tina Zhang <[email protected]>
> Subject: [PATCH v2 6/9] target/i386: Do not broadcast injected MCEs for
>  Hygon
> X-Mailer: git-send-email 2.43.7
> 
> cpu_x86_support_mca_broadcast() excludes AMD CPUs because QEMU handles
> AMD injected MCEs as local machine checks, not as Intel-style broadcast
> MCEs.  Hygon Dhyana missed that exclusion: it is not an AMD vendor CPU
> and its family is greater than 6, so QEMU reported MCA broadcast
> support.
> 
> This affects QEMU's synthetic MCE injection paths.  KVM memory-failure
> injection uses this helper to decide whether to set MCE_INJECT_BROADCAST.
> HMP 'mce -b' uses it to decide whether a broadcast request is valid.
> With a multi-vCPU Dhyana guest, QEMU could fan out an injected MCE to
> secondary vCPUs and populate extra bank records.
> 
> Linux routes Hygon through the AMD MCE feature initialization path and
> does not use Intel/Zhaoxin LMCE broadcast handling for Hygon.  Do not
> advertise Intel-style MCA broadcast support for Hygon in QEMU's injected
> MCE paths.
> 
> This is limited to the MCE broadcast-support decision.  It does not claim
> that all Hygon MCE/MCA behavior is identical to AMD.
> 
> Signed-off-by: Tina Zhang <[email protected]>
> ---
>  target/i386/helper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Zhao Liu <[email protected]>