From: Sandipan Das <sandipan.das@amd.com>
To: Michael Tokarev <mjt@tls.msk.ru>,
Dongli Zhang <dongli.zhang@oracle.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Cc: pbonzini@redhat.com, zhao1.liu@intel.com, mtosatti@redhat.com,
babu.moger@amd.com, likexu@tencent.com, like.xu.linux@gmail.com,
groug@kaod.org, khorenko@virtuozzo.com,
alexander.ivanov@virtuozzo.com, den@virtuozzo.com,
davydov-max@yandex-team.ru, xiaoyao.li@intel.com,
dapeng1.mi@linux.intel.com, joe.jin@oracle.com,
ewanhai-oc@zhaoxin.com, ewanhai@zhaoxin.com
Subject: Re: [PATCH v8 1/7] target/i386/kvm: set KVM_PMU_CAP_DISABLE if "-pmu" is configured
Date: Thu, 1 Oct 2026 16:13:26 +0530 [thread overview]
Message-ID: <6ee6f858-37f6-4acb-8253-acd3cec584ad@amd.com> (raw)
In-Reply-To: <18ff5158-a515-4659-8388-5bcc074afb94@tls.msk.ru>
On 01-10-2026 15:30, Michael Tokarev wrote:
> On 10/1/26 11:54, Sandipan Das wrote:
>> On 01-10-2026 14:02, Michael Tokarev wrote:
> ...
>
>>> When booting windows11 VM with -cpu EPYC-Rome-v4 -enable-kvm, the
>>> guest enters tight CPU loop while displaying a boot screen, before
>>> it starts showing up the rotating circle (which shows boot progress).
>
>
>> What happens if you use "-cpu EPYC-Rome-v4,+pmu"?
>
> With that, it boots fine, just like before this patch.
> I checked current master too - same, +pmu fixes it.
>
A guest OS cannot expect a functioning PMU if the hypervisor has disabled
it. Linux runs a basic sanity test to determine this. See:
https://github.com/torvalds/linux/blob/master/arch/x86/events/core.c#L268
next prev parent reply other threads:[~2026-10-01 10:43 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-30 7:42 [PATCH v8 0/7] target/i386/kvm/pmu: PMU Enhancement, Bugfix and Cleanup Dongli Zhang
2025-12-30 7:42 ` [PATCH v8 1/7] target/i386/kvm: set KVM_PMU_CAP_DISABLE if "-pmu" is configured Dongli Zhang
2026-10-01 8:32 ` Michael Tokarev
2026-10-01 8:54 ` Sandipan Das
2026-10-01 10:00 ` Michael Tokarev
2026-10-01 10:43 ` Sandipan Das [this message]
2026-10-01 11:05 ` Michael Tokarev
2026-10-01 11:12 ` Sandipan Das
2026-10-06 8:41 ` Sandipan Das
2026-10-07 0:51 ` Dongli Zhang
2025-12-30 7:42 ` [PATCH v8 2/7] target/i386/kvm: extract unrelated code out of kvm_x86_build_cpuid() Dongli Zhang
2025-12-30 7:42 ` [PATCH v8 3/7] target/i386/kvm: rename architectural PMU variables Dongli Zhang
2025-12-30 7:42 ` [PATCH v8 4/7] target/i386/kvm: query kvm.enable_pmu parameter Dongli Zhang
2026-01-02 22:59 ` Chen, Zide
2026-01-05 20:21 ` Dongli Zhang
2026-01-06 21:03 ` Chen, Zide
2026-01-07 8:05 ` Dongli Zhang
2026-01-07 18:09 ` Chen, Zide
2025-12-30 7:42 ` [PATCH v8 5/7] target/i386/kvm: reset AMD PMU registers during VM reset Dongli Zhang
2025-12-30 7:42 ` [PATCH v8 6/7] target/i386/kvm: support perfmon-v2 for reset Dongli Zhang
2025-12-30 7:42 ` [PATCH v8 7/7] target/i386/kvm: don't stop Intel PMU counters Dongli Zhang
2026-01-03 0:27 ` Chen, Zide
2026-01-05 20:24 ` Dongli Zhang
2026-01-06 21:04 ` Chen, Zide
2026-01-07 8:36 ` Dongli Zhang
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