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

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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: 8de4a1c816 ("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>
This commit is contained in:
Tina Zhang 2026-05-22 12:00:14 +08:00 committed by Paolo Bonzini
parent d9c41dc531
commit 9a12fa5213
1 changed files with 7 additions and 5 deletions
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12
arch/x86/kvm/svm/avic.c
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@ -1300,12 +1300,14 @@ bool __init avic_hardware_setup(void)
}
/*
* Disable IPI virtualization for AMD Family 17h CPUs (Zen1 and Zen2)
* due to erratum 1235, which results in missed VM-Exits on the sender
* and thus missed wake events for blocking vCPUs due to the CPU
* failing to see a software update to clear IsRunning.
* Disable IPI virtualization for AMD Family 17h (Zen1 and Zen2) and
* Hygon Family 18h (derived from AMD Zen1) CPUs due to erratum 1235,
* which results in missed VM-Exits on the sender and thus missed wake
* events for blocking vCPUs due to the CPU failing to see a software
* update to clear IsRunning.
*/
enable_ipiv = enable_ipiv && boot_cpu_data.x86 != 0x17;
if (boot_cpu_data.x86 == 0x17 || boot_cpu_data.x86 == 0x18)
enable_ipiv = false;
amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);