On Thu, May 29, 2025 at 04:39:49PM -0700, Sean Christopherson wrote: >WARN and kill the VM instead of panicking the host if KVM attempts to set >or query MSR interception for an unsupported MSR. Accessing the MSR >interception bitmaps only meaningfully affects post-VMRUN behavior, and >KVM_BUG_ON() is guaranteed to prevent the current vCPU from doing VMRUN, >i.e. there is no need to panic the entire host. > >Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> >--- > arch/x86/kvm/svm/svm.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > >diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c >index 36a99b87a47f..d5d11cb0c987 100644 >--- a/arch/x86/kvm/svm/svm.c >+++ b/arch/x86/kvm/svm/svm.c >@@ -827,7 +827,8 @@ static bool msr_write_intercepted(struct kvm_vcpu *vcpu, u32 msr) > bit_write = 2 * (msr & 0x0f) + 1; > tmp = msrpm[offset]; not an issue with this patch. but shouldn't the offset be checked against MSR_INVALID before being used to index msrpm[]? > >- BUG_ON(offset == MSR_INVALID); >+ if (KVM_BUG_ON(offset == MSR_INVALID, vcpu->kvm)) >+ return false; > > return test_bit(bit_write, &tmp); > } >@@ -858,7 +859,8 @@ static void set_msr_interception_bitmap(struct kvm_vcpu *vcpu, u32 *msrpm, > bit_write = 2 * (msr & 0x0f) + 1; > tmp = msrpm[offset]; > >- BUG_ON(offset == MSR_INVALID); >+ if (KVM_BUG_ON(offset == MSR_INVALID, vcpu->kvm)) >+ return; > > read ? clear_bit(bit_read, &tmp) : set_bit(bit_read, &tmp); > write ? clear_bit(bit_write, &tmp) : set_bit(bit_write, &tmp); >-- >2.49.0.1204.g71687c7c1d-goog >
