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