Commit 7d390a9d authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: TDX: Use kvm_arch_vcpu.host_debugctl to restore the host's DEBUGCTL 

Use the kvm_arch_vcpu.host_debugctl snapshot to restore DEBUGCTL after
running a TD vCPU.  The final TDX series rebase was mishandled, likely due
to commit fb71c795 ("KVM: x86: Snapshot the host's DEBUGCTL in common
x86") deleting the same line of code from vmx.h, i.e. creating a semantic
conflict of sorts, but no syntactic conflict.

Using the version in kvm_vcpu_arch picks up the ulong => u64 fix (which
isn't relevant to TDX) as well as the IRQ fix from commit 189ecdb3
("KVM: x86: Snapshot the host's DEBUGCTL after disabling IRQs").

Link: https://lore.kernel.org/all/20250307212053.2948340-10-pbonzini@redhat.com


Cc: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 8af09903 ("KVM: TDX: Save and restore IA32_DEBUGCTL")
Reviewed-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20250610232010.162191-2-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 28224ef0

arch/x86/kvm/vmx/common.h

+0 −2
Original line number Diff line number Diff line
@@ -53,8 +53,6 @@ struct vcpu_vt { 
#ifdef CONFIG_X86_64

	u64		msr_host_kernel_gs_base;

#endif



	unsigned long	host_debugctlmsr;

};



#ifdef CONFIG_KVM_INTEL_TDX

arch/x86/kvm/vmx/tdx.c

+2 −4
Original line number Diff line number Diff line
@@ -785,8 +785,6 @@ void tdx_prepare_switch_to_guest(struct kvm_vcpu *vcpu) 
	else

		vt->msr_host_kernel_gs_base = read_msr(MSR_KERNEL_GS_BASE);



	vt->host_debugctlmsr = get_debugctlmsr();



	vt->guest_state_loaded = true;

}
@@ -1062,8 +1060,8 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit) 


	tdx_vcpu_enter_exit(vcpu);



	if (vt->host_debugctlmsr & ~TDX_DEBUGCTL_PRESERVED)

		update_debugctlmsr(vt->host_debugctlmsr);

	if (vcpu->arch.host_debugctl & ~TDX_DEBUGCTL_PRESERVED)

		update_debugctlmsr(vcpu->arch.host_debugctl);



	tdx_load_host_xsave_state(vcpu);

	tdx->guest_entered = true;