Commit b33bb78a authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: nVMX: Handle split-lock #AC exceptions that happen in L2 



Mark #ACs that won't be reinjected to the guest as wanted by L0 so that
KVM handles split-lock #AC from L2 instead of forwarding the exception to
L1.  Split-lock #AC isn't yet virtualized, i.e. L1 will treat it like a
regular #AC and do the wrong thing, e.g. reinject it into L2.

Fixes: e6f8b6c1 ("KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest")
Cc: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210622172244.3561540-1-seanjc@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 31c65657

arch/x86/kvm/vmx/nested.c

+3 −0
Original line number Diff line number Diff line
@@ -5833,6 +5833,9 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, 
		else if (is_breakpoint(intr_info) &&

			 vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)

			return true;

		else if (is_alignment_check(intr_info) &&

			 !vmx_guest_inject_ac(vcpu))

			return true;

		return false;

	case EXIT_REASON_EXTERNAL_INTERRUPT:

		return true;

arch/x86/kvm/vmx/vmcs.h

+5 −0
Original line number Diff line number Diff line
@@ -117,6 +117,11 @@ static inline bool is_gp_fault(u32 intr_info) 
	return is_exception_n(intr_info, GP_VECTOR);

}



static inline bool is_alignment_check(u32 intr_info)

{

	return is_exception_n(intr_info, AC_VECTOR);

}



static inline bool is_machine_check(u32 intr_info)

{

	return is_exception_n(intr_info, MC_VECTOR);

arch/x86/kvm/vmx/vmx.c

+2 −2
Original line number Diff line number Diff line
@@ -4743,7 +4743,7 @@ static int handle_machine_check(struct kvm_vcpu *vcpu) 
 *  - Guest has #AC detection enabled in CR0

 *  - Guest EFLAGS has AC bit set

 */

static inline bool guest_inject_ac(struct kvm_vcpu *vcpu)

bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu)

{

	if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))

		return true;
@@ -4851,7 +4851,7 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu) 
		kvm_run->debug.arch.exception = ex_no;

		break;

	case AC_VECTOR:

		if (guest_inject_ac(vcpu)) {

		if (vmx_guest_inject_ac(vcpu)) {

			kvm_queue_exception_e(vcpu, AC_VECTOR, error_code);

			return 1;

		}

arch/x86/kvm/vmx/vmx.h

+1 −0
Original line number Diff line number Diff line
@@ -376,6 +376,7 @@ void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg); 
void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);

u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);



bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu);

void vmx_update_exception_bitmap(struct kvm_vcpu *vcpu);

void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);

bool vmx_nmi_blocked(struct kvm_vcpu *vcpu);