X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=arch%2Fx86%2Fkvm%2Fsvm%2Fsvm.c;h=664d20f0689c8bb43f35bbad59be47843ca8679e;hb=d842bc6c0579ca7643eed029beabab3ac562a335;hp=63488d3beb5b494c10ce14ad4753b790aef81eed;hpb=4b639a9f82fcf15497d1613a29aa1df798a24029;p=linux-2.6-microblaze.git

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 63488d3beb5b..664d20f0689c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2954,7 +2954,16 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 			svm_disable_lbrv(vcpu);
 		break;
 	case MSR_VM_HSAVE_PA:
-		svm->nested.hsave_msr = data;
+		/*
+		 * Old kernels did not validate the value written to
+		 * MSR_VM_HSAVE_PA.  Allow KVM_SET_MSR to set an invalid
+		 * value to allow live migrating buggy or malicious guests
+		 * originating from those kernels.
+		 */
+		if (!msr->host_initiated && !page_address_valid(vcpu, data))
+			return 1;
+
+		svm->nested.hsave_msr = data & PAGE_MASK;
 		break;
 	case MSR_VM_CR:
 		return svm_set_vm_cr(vcpu, data);
@@ -4300,6 +4309,7 @@ static int svm_smi_allowed(struct kvm_vcpu *vcpu, bool for_injection)
 static int svm_enter_smm(struct kvm_vcpu *vcpu, char *smstate)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
+	struct kvm_host_map map_save;
 	int ret;
 
 	if (is_guest_mode(vcpu)) {
@@ -4315,6 +4325,29 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, char *smstate)
 		ret = nested_svm_vmexit(svm);
 		if (ret)
 			return ret;
+
+		/*
+		 * KVM uses VMCB01 to store L1 host state while L2 runs but
+		 * VMCB01 is going to be used during SMM and thus the state will
+		 * be lost. Temporary save non-VMLOAD/VMSAVE state to the host save
+		 * area pointed to by MSR_VM_HSAVE_PA. APM guarantees that the
+		 * format of the area is identical to guest save area offsetted
+		 * by 0x400 (matches the offset of 'struct vmcb_save_area'
+		 * within 'struct vmcb'). Note: HSAVE area may also be used by
+		 * L1 hypervisor to save additional host context (e.g. KVM does
+		 * that, see svm_prepare_guest_switch()) which must be
+		 * preserved.
+		 */
+		if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr),
+				 &map_save) == -EINVAL)
+			return 1;
+
+		BUILD_BUG_ON(offsetof(struct vmcb, save) != 0x400);
+
+		svm_copy_vmrun_state(&svm->vmcb01.ptr->save,
+				     map_save.hva + 0x400);
+
+		kvm_vcpu_unmap(vcpu, &map_save, true);
 	}
 	return 0;
 }
@@ -4322,13 +4355,14 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, char *smstate)
 static int svm_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
-	struct kvm_host_map map;
+	struct kvm_host_map map, map_save;
 	int ret = 0;
 
 	if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) {
 		u64 saved_efer = GET_SMSTATE(u64, smstate, 0x7ed0);
 		u64 guest = GET_SMSTATE(u64, smstate, 0x7ed8);
 		u64 vmcb12_gpa = GET_SMSTATE(u64, smstate, 0x7ee0);
+		struct vmcb *vmcb12;
 
 		if (guest) {
 			if (!guest_cpuid_has(vcpu, X86_FEATURE_SVM))
@@ -4344,8 +4378,25 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
 			if (svm_allocate_nested(svm))
 				return 1;
 
-			ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, map.hva);
+			vmcb12 = map.hva;
+
+			nested_load_control_from_vmcb12(svm, &vmcb12->control);
+
+			ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12);
 			kvm_vcpu_unmap(vcpu, &map, true);
+
+			/*
+			 * Restore L1 host state from L1 HSAVE area as VMCB01 was
+			 * used during SMM (see svm_enter_smm())
+			 */
+			if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr),
+					 &map_save) == -EINVAL)
+				return 1;
+
+			svm_copy_vmrun_state(map_save.hva + 0x400,
+					     &svm->vmcb01.ptr->save);
+
+			kvm_vcpu_unmap(vcpu, &map_save, true);
 		}
 	}