@@ -840,6 +840,34 @@ Returns a buffer containing the XSAVE area.
 * -KVM_EAGAIN - the selected vCPU can't be introspected yet
 * -KVM_ENOMEM - there is not enough memory to allocate the reply
 
+19. KVMI_VCPU_SET_XSAVE
+-----------------------
+
+:Architectures: x86
+:Versions: >= 1
+:Parameters:
+
+::
+
+	struct kvmi_vcpu_hdr;
+	struct kvmi_vcpu_set_xsave {
+		struct kvm_xsave xsave;
+	};
+
+:Returns:
+
+::
+
+	struct kvmi_error_code;
+
+Modifies the XSAVE area.
+
+:Errors:
+
+* -KVM_EINVAL - the selected vCPU is invalid
+* -KVM_EINVAL - the padding is not zero
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+
 Events
 ======
 

@@ -115,4 +115,8 @@ struct kvmi_vcpu_get_xsave_reply {
 	struct kvm_xsave xsave;
 };
 
+struct kvmi_vcpu_set_xsave {
+	struct kvm_xsave xsave;
+};
+
 #endif /* _UAPI_ASM_X86_KVMI_H */

@@ -213,6 +213,25 @@ static int handle_vcpu_get_xsave(const struct kvmi_vcpu_msg_job *job,
 	return err;
 }
 
+static int handle_vcpu_set_xsave(const struct kvmi_vcpu_msg_job *job,
+				 const struct kvmi_msg_hdr *msg,
+				 const void *req)
+{
+	const struct kvm_xsave *area = req;
+	size_t cmd_size;
+	int ec = 0;
+
+	cmd_size = sizeof(struct kvmi_vcpu_hdr) + sizeof(*area);
+
+	if (cmd_size > msg->size)
+		ec = -KVM_EINVAL;
+	else if (kvm_vcpu_ioctl_x86_set_xsave(job->vcpu,
+					      (struct kvm_xsave *) area))
+		ec = -KVM_EINVAL;
+
+	return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
+}
+
 static const kvmi_vcpu_msg_job_fct msg_vcpu[] = {
 	[KVMI_VCPU_CONTROL_CR]       = handle_vcpu_control_cr,
 	[KVMI_VCPU_GET_CPUID]        = handle_vcpu_get_cpuid,

@@ -222,6 +241,7 @@ static const kvmi_vcpu_msg_job_fct msg_vcpu[] = {
 	[KVMI_VCPU_GET_XSAVE]        = handle_vcpu_get_xsave,
 	[KVMI_VCPU_INJECT_EXCEPTION] = handle_vcpu_inject_exception,
 	[KVMI_VCPU_SET_REGISTERS]    = handle_vcpu_set_registers,
+	[KVMI_VCPU_SET_XSAVE]        = handle_vcpu_set_xsave,
 };
 
 kvmi_vcpu_msg_job_fct kvmi_arch_vcpu_msg_handler(u16 id)

@@ -45,6 +45,7 @@ enum {
 	KVMI_VCPU_INJECT_EXCEPTION = KVMI_VCPU_MESSAGE_ID(7),
 	KVMI_VCPU_GET_XCR          = KVMI_VCPU_MESSAGE_ID(8),
 	KVMI_VCPU_GET_XSAVE        = KVMI_VCPU_MESSAGE_ID(9),
+	KVMI_VCPU_SET_XSAVE        = KVMI_VCPU_MESSAGE_ID(10),
 
 	KVMI_NEXT_VCPU_MESSAGE
 };

@@ -1437,21 +1437,35 @@ static void test_cmd_vcpu_get_xcr(struct kvm_vm *vm)
 	cmd_vcpu_get_xcr(vm, xcr1, &value, -KVM_EINVAL);
 }
 
-static void cmd_vcpu_get_xsave(struct kvm_vm *vm)
+static void cmd_vcpu_get_xsave(struct kvm_vm *vm, struct kvm_xsave *rpl)
 {
 	struct {
 		struct kvmi_msg_hdr hdr;
 		struct kvmi_vcpu_hdr vcpu_hdr;
 	} req = {};
-	struct kvm_xsave rpl;
 
 	test_vcpu0_command(vm, KVMI_VCPU_GET_XSAVE, &req.hdr, sizeof(req),
-			   &rpl, sizeof(rpl), 0);
+			   rpl, sizeof(*rpl), 0);
+}
+
+static void cmd_vcpu_set_xsave(struct kvm_vm *vm, struct kvm_xsave *rpl)
+{
+	struct {
+		struct kvmi_msg_hdr hdr;
+		struct kvmi_vcpu_hdr vcpu_hdr;
+		struct kvm_xsave xsave;
+	} req = {};
+
+	memcpy(&req.xsave, rpl, sizeof(*rpl));
+
+	test_vcpu0_command(vm, KVMI_VCPU_SET_XSAVE, &req.hdr, sizeof(req),
+			   NULL, 0, 0);
 }
 
-static void test_cmd_vcpu_get_xsave(struct kvm_vm *vm)
+static void test_cmd_vcpu_xsave(struct kvm_vm *vm)
 {
 	struct kvm_cpuid_entry2 *entry;
+	struct kvm_xsave xsave;
 
 	entry = kvm_get_supported_cpuid_entry(1);
 	if (!(entry->ecx & X86_FEATURE_XSAVE)) {

@@ -1459,7 +1473,8 @@ static void test_cmd_vcpu_get_xsave(struct kvm_vm *vm)
 		return;
 	}
 
-	cmd_vcpu_get_xsave(vm);
+	cmd_vcpu_get_xsave(vm, &xsave);
+	cmd_vcpu_set_xsave(vm, &xsave);
 }
 
 static void test_introspection(struct kvm_vm *vm)

@@ -1489,7 +1504,7 @@ static void test_introspection(struct kvm_vm *vm)
 	test_cmd_vcpu_inject_exception(vm);
 	test_event_xsetbv(vm);
 	test_cmd_vcpu_get_xcr(vm);
-	test_cmd_vcpu_get_xsave(vm);
+	test_cmd_vcpu_xsave(vm);
 
 	unhook_introspection(vm);
 }