Commit 89dccf82 authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

KVM: x86: smm: check for failures on smm entry 



In the rare case of the failure on SMM entry, the KVM should at
least terminate the VM instead of going south.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221025124741.228045-16-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a7662aa5

arch/x86/kvm/smm.c

+15 −4
Original line number Diff line number Diff line
@@ -213,11 +213,17 @@ void enter_smm(struct kvm_vcpu *vcpu) 
	 * Give enter_smm() a chance to make ISA-specific changes to the vCPU

	 * state (e.g. leave guest mode) after we've saved the state into the

	 * SMM state-save area.

	 *

	 * Kill the VM in the unlikely case of failure, because the VM

	 * can be in undefined state in this case.

	 */

	static_call(kvm_x86_enter_smm)(vcpu, buf);

	if (static_call(kvm_x86_enter_smm)(vcpu, buf))

		goto error;



	kvm_smm_changed(vcpu, true);

	kvm_vcpu_write_guest(vcpu, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf));



	if (kvm_vcpu_write_guest(vcpu, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf)))

		goto error;



	if (static_call(kvm_x86_get_nmi_mask)(vcpu))

		vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;
@@ -237,7 +243,8 @@ void enter_smm(struct kvm_vcpu *vcpu) 
	dt.address = dt.size = 0;

	static_call(kvm_x86_set_idt)(vcpu, &dt);



	kvm_set_dr(vcpu, 7, DR7_FIXED_1);

	if (WARN_ON_ONCE(kvm_set_dr(vcpu, 7, DR7_FIXED_1)))

		goto error;



	cs.selector = (vcpu->arch.smbase >> 4) & 0xffff;

	cs.base = vcpu->arch.smbase;
@@ -266,11 +273,15 @@ void enter_smm(struct kvm_vcpu *vcpu) 


#ifdef CONFIG_X86_64

	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))

		static_call(kvm_x86_set_efer)(vcpu, 0);

		if (static_call(kvm_x86_set_efer)(vcpu, 0))

			goto error;

#endif



	kvm_update_cpuid_runtime(vcpu);

	kvm_mmu_reset_context(vcpu);

	return;

error:

	kvm_vm_dead(vcpu->kvm);

}



static void rsm_set_desc_flags(struct kvm_segment *desc, u32 flags)