KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235)

KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235)

Hygon Family 18h CPUs are derived from AMD Family 17h (Zen1) silicon and
share the same erratum #1235: hardware may read a stale IsRunning=1 bit
during ICR write emulation and silently fail to generate an
AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit on the sending vCPU.

The absence of the VM-Exit causes KVM to miss the required wakeup of
blocking target vCPUs, leading to hung vCPUs and unbounded delays in
guest execution.

Extend the existing AMD Family 17h erratum #1235 workaround to also cover
Hygon Family 18h.  With IPI virtualization disabled, KVM never sets
IsRunning=1 in the Physical ID table, so every non-self IPI generates a
VM-Exit and is correctly emulated.

Fixes: 8de4a1c8164e ("KVM: SVM: Disable (x2)AVIC IPI virtualization if CPU has erratum #1235")
Cc: <stable@vger.kernel.org>
Signed-off-by: Tina Zhang <zhang_wei@open-hieco.net>
Message-ID: <20260522040014.3380201-1-zhang_wei@open-hieco.net>