6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson <seanjc@xxxxxxxxxx> commit 189ecdb3e112da703ac0699f4ec76aa78122f911 upstream. Snapshot the host's DEBUGCTL after disabling IRQs, as perf can toggle debugctl bits from IRQ context, e.g. when enabling/disabling events via smp_call_function_single(). Taking the snapshot (long) before IRQs are disabled could result in KVM effectively clobbering DEBUGCTL due to using a stale snapshot. Cc: stable@xxxxxxxxxxxxxxx Reviewed-and-tested-by: Ravi Bangoria <ravi.bangoria@xxxxxxx> Link: https://lore.kernel.org/r/20250227222411.3490595-6-seanjc@xxxxxxxxxx Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4976,7 +4976,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu /* Save host pkru register if supported */ vcpu->arch.host_pkru = read_pkru(); - vcpu->arch.host_debugctl = get_debugctlmsr(); /* Apply any externally detected TSC adjustments (due to suspend) */ if (unlikely(vcpu->arch.tsc_offset_adjustment)) { @@ -10961,6 +10960,8 @@ static int vcpu_enter_guest(struct kvm_v set_debugreg(0, 7); } + vcpu->arch.host_debugctl = get_debugctlmsr(); + guest_timing_enter_irqoff(); for (;;) {
