Commit 8af09903 authored by Adrian Hunter's avatar Adrian Hunter Committed by Paolo Bonzini
Browse files

KVM: TDX: Save and restore IA32_DEBUGCTL 



Save the IA32_DEBUGCTL MSR before entering a TDX VCPU and restore it
afterwards.  The TDX Module preserves bits 1, 12, and 14, so if no
other bits are set, no restore is done.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Message-ID: <20250129095902.16391-12-adrian.hunter@intel.com>
Reviewed-by: default avatarXiayao Li <xiaoyao.li@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 6d415778

arch/x86/kvm/vmx/tdx.c

+10 −1
Original line number Diff line number Diff line
@@ -688,6 +688,8 @@ 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;

}
@@ -831,11 +833,15 @@ static void tdx_load_host_xsave_state(struct kvm_vcpu *vcpu) 
	if (kvm_host.xss != (kvm_tdx->xfam & kvm_caps.supported_xss))

		wrmsrl(MSR_IA32_XSS, kvm_host.xss);

}

EXPORT_SYMBOL_GPL(kvm_load_host_xsave_state);



#define TDX_DEBUGCTL_PRESERVED (DEBUGCTLMSR_BTF | \

				DEBUGCTLMSR_FREEZE_PERFMON_ON_PMI | \

				DEBUGCTLMSR_FREEZE_IN_SMM)



fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)

{

	struct vcpu_tdx *tdx = to_tdx(vcpu);

	struct vcpu_vt *vt = to_vt(vcpu);



	/*

	 * force_immediate_exit requires vCPU entering for events injection with
@@ -851,6 +857,9 @@ 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);



	tdx_load_host_xsave_state(vcpu);

	tdx->guest_entered = true;