CVE-2026-64172

In the Linux kernel, the following vulnerability has been resolved:

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.