On Thu, Aug 14, 2025, Sasha Levin wrote:
From: Sean Christopherson seanjc@google.com
[ Upstream commit 8a4351ac302cd8c19729ba2636acfd0467c22ae8 ]
Move VMX's logic to check DEBUGCTL values into a standalone helper so that the code can be used by nested VM-Enter to apply the same logic to the value being loaded from vmcs12.
KVM needs to explicitly check vmcs12->guest_ia32_debugctl on nested VM-Enter, as hardware may support features that KVM does not, i.e. relying on hardware to detect invalid guest state will result in false negatives. Unfortunately, that means applying KVM's funky suppression of BTF and LBR to vmcs12 so as not to break existing guests.
No functional change intended.
Reviewed-by: Dapeng Mi dapeng1.mi@linux.intel.com Link: https://lore.kernel.org/r/20250610232010.162191-6-seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com Stable-dep-of: 6b1dd26544d0 ("KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while running the guest") Signed-off-by: Sasha Levin sashal@kernel.org
Acked-by: Sean Christopherson seanjc@google.com