6.12-stable review patch. If anyone has any objections, please let me know.
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From: Sean Christopherson seanjc@google.com
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@vger.kernel.org Reviewed-and-tested-by: Ravi Bangoria ravi.bangoria@amd.com Link: https://lore.kernel.org/r/20250227222411.3490595-6-seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -4993,7 +4993,6 @@ 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)) { @@ -10965,6 +10964,8 @@ static int vcpu_enter_guest(struct kvm_v set_debugreg(0, 7); }
+ vcpu->arch.host_debugctl = get_debugctlmsr(); + guest_timing_enter_irqoff();
for (;;) {