linux-kernel - [PATCH 0/3] KVM: x86/pmu: Fix accesses to PMU MSRs in two corner cases

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Date:   Mon, 26 Dec 2022 19:17:07 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 0/3] KVM: x86/pmu: Fix accesses to PMU MSRs in two corner cases 

When PMU is disabled globally, the msr_list reported by KVM will still
expose a not minor number of PMU msrs, patch 1 is a quick fix and
stable trees will be much needed. Note, a more maintenance-friendly
approach [1] suggested by Sean is certainly in the works, but users are
now in desperate need of a pill.

The second case is where the host user space of a low version PMU can
still see the higher version PMU features from the msr_list exposed by KVM,
and subsequent read and write access failures also causes KVM regression.
Note, a more thorough clean-up move is also in the development pipeline.

Please consider adding cc: stable to the first two patches so that further
refactoring of the same issues can be focused on upstream maintenance.

[1] https://lore.kernel.org/all/20220805172945.35412-4-seanjc@google.com/

Off-topic, two more independent KVM fixes also need to be reviewed:
- https://lore.kernel.org/kvm/20221109115952.92816-1-likexu@tencent.com/
- https://lore.kernel.org/kvm/20221205122048.16023-1-likexu@tencent.com/

Like Xu (3):
  KVM: x86: Omit PMU MSRs from KVM_GET_MSR_INDEX_LIST if !enable_pmu
  KVM: x86: Ignore host accesses to higher version PMU features MSRs
  KVM: x86: Fix a typo about msrs_to_save_all[] in kvm_init_msr_list()

 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/x86.c              | 34 ++++++++++++++++++++++++++++++---
 2 files changed, 32 insertions(+), 3 deletions(-)

-- 
2.39.0