This is a note to let you know that I've just added the patch titled KVM: x86: Fix uninitialized eoi_exit_bitmap usage in vcpu_load_eoi_exitmap() to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kvm-x86-fix-uninitialized-eoi_exit_bitmap-usage-in-vcpu_load_eoi_exitmap.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c5adbb3af051079f35abfa26551107e2c653087f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E9=BB=84=E4=B9=90?= <huangle1@xxxxxx> Date: Mon, 15 Nov 2021 14:08:29 +0000 Subject: KVM: x86: Fix uninitialized eoi_exit_bitmap usage in vcpu_load_eoi_exitmap() From: 黄乐 <huangle1@xxxxxx> commit c5adbb3af051079f35abfa26551107e2c653087f upstream. In vcpu_load_eoi_exitmap(), currently the eoi_exit_bitmap[4] array is initialized only when Hyper-V context is available, in other path it is just passed to kvm_x86_ops.load_eoi_exitmap() directly from on the stack, which would cause unexpected interrupt delivery/handling issues, e.g. an *old* linux kernel that relies on PIT to do clock calibration on KVM might randomly fail to boot. Fix it by passing ioapic_handled_vectors to load_eoi_exitmap() when Hyper-V context is not available. Fixes: f2bc14b69c38 ("KVM: x86: hyper-v: Prepare to meet unallocated Hyper-V context") Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Signed-off-by: Huang Le <huangle1@xxxxxx> Message-Id: <62115b277dab49ea97da5633f8522daf@xxxxxx> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kvm/x86.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9429,12 +9429,16 @@ static void vcpu_load_eoi_exitmap(struct if (!kvm_apic_hw_enabled(vcpu->arch.apic)) return; - if (to_hv_vcpu(vcpu)) + if (to_hv_vcpu(vcpu)) { bitmap_or((ulong *)eoi_exit_bitmap, vcpu->arch.ioapic_handled_vectors, to_hv_synic(vcpu)->vec_bitmap, 256); + static_call(kvm_x86_load_eoi_exitmap)(vcpu, eoi_exit_bitmap); + return; + } - static_call(kvm_x86_load_eoi_exitmap)(vcpu, eoi_exit_bitmap); + static_call(kvm_x86_load_eoi_exitmap)( + vcpu, (u64 *)vcpu->arch.ioapic_handled_vectors); } void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, Patches currently in stable-queue which might be from huangle1@xxxxxx are queue-5.15/kvm-x86-fix-uninitialized-eoi_exit_bitmap-usage-in-vcpu_load_eoi_exitmap.patch