--- .before/arch/x86/kvm/vmx.c	2010-06-13 15:01:29.000000000 +0300
+++ .after/arch/x86/kvm/vmx.c	2010-06-13 15:01:29.000000000 +0300
@@ -299,6 +299,42 @@ struct nested_vmx {
 	int l2_vmcs_num;
 };
 
+enum vmcs_field_type {
+	VMCS_FIELD_TYPE_U16 = 0,
+	VMCS_FIELD_TYPE_U64 = 1,
+	VMCS_FIELD_TYPE_U32 = 2,
+	VMCS_FIELD_TYPE_ULONG = 3
+};
+
+#define VMCS_FIELD_LENGTH_OFFSET 13
+#define VMCS_FIELD_LENGTH_MASK 0x6000
+
+static inline int vmcs_field_type(unsigned long field)
+{
+	if (0x1 & field)	/* one of the *_HIGH fields, all are 32 bit */
+		return VMCS_FIELD_TYPE_U32;
+	return (VMCS_FIELD_LENGTH_MASK & field) >> 13;
+}
+
+static inline int vmcs_field_size(int field_type, struct kvm_vcpu *vcpu)
+{
+	switch (field_type) {
+	case VMCS_FIELD_TYPE_U16:
+		return 2;
+	case VMCS_FIELD_TYPE_U32:
+		return 4;
+	case VMCS_FIELD_TYPE_U64:
+		return 8;
+	case VMCS_FIELD_TYPE_ULONG:
+#ifdef CONFIG_X86_64
+		if (is_long_mode(vcpu))
+			return 8;
+#endif
+		return 4;
+	}
+	return 0; /* should never happen */
+}
+
 struct vcpu_vmx {
 	struct kvm_vcpu       vcpu;
 	struct list_head      local_vcpus_link;
@@ -4184,6 +4220,189 @@ static int handle_vmclear(struct kvm_vcp
 	return 1;
 }
 
+static inline bool nested_vmcs_read_any(struct kvm_vcpu *vcpu,
+					unsigned long field, u64 *ret)
+{
+	short offset = vmcs_field_to_offset(field);
+	char *p;
+
+	if (offset < 0)
+		return 0;
+	if (!to_vmx(vcpu)->nested.current_l2_page)
+		return 0;
+
+	p = ((char *)(get_shadow_vmcs(vcpu))) + offset;
+
+	switch (vmcs_field_type(field)) {
+	case VMCS_FIELD_TYPE_ULONG:
+		*ret = *((unsigned long *)p);
+		return 1;
+	case VMCS_FIELD_TYPE_U16:
+		*ret = (u16) *((unsigned long *)p);
+		return 1;
+	case VMCS_FIELD_TYPE_U32:
+		*ret = (u32) *((unsigned long *)p);
+		return 1;
+	case VMCS_FIELD_TYPE_U64:
+		*ret = *((u64 *)p);
+		return 1;
+	default:
+		return 0; /* can never happen. */
+	}
+}
+
+static int handle_vmread_reg(struct kvm_vcpu *vcpu, int reg,
+			     unsigned long field)
+{
+	u64 field_value;
+	if (!nested_vmcs_read_any(vcpu, field, &field_value))
+		return 0;
+
+#ifdef CONFIG_X86_64
+	switch (vmcs_field_type(field)) {
+	case VMCS_FIELD_TYPE_U64: case VMCS_FIELD_TYPE_ULONG:
+		if (!is_long_mode(vcpu)) {
+			kvm_register_write(vcpu, reg+1, field_value >> 32);
+			field_value = (u32)field_value;
+		}
+	}
+#endif
+	kvm_register_write(vcpu, reg, field_value);
+	return 1;
+}
+
+static int handle_vmread_mem(struct kvm_vcpu *vcpu, gva_t gva,
+			     unsigned long field)
+{
+	u64 field_value;
+	if (!nested_vmcs_read_any(vcpu, field, &field_value))
+		return 0;
+
+	/* It's ok to use *_system, because handle_vmread verifies cpl=0 */
+	kvm_write_guest_virt_system(gva, &field_value,
+			     vmcs_field_size(vmcs_field_type(field), vcpu),
+			     vcpu, NULL);
+	return 1;
+}
+
+static int handle_vmread(struct kvm_vcpu *vcpu)
+{
+	unsigned long field;
+	unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
+	u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+	gva_t gva = 0;
+	int read_succeed;
+
+	if (!nested_vmx_check_permission(vcpu))
+		return 1;
+
+	if (!nested_map_current(vcpu)) {
+		printk(KERN_INFO "%s invalid shadow vmcs\n", __func__);
+		set_rflags_to_vmx_fail_invalid(vcpu);
+		return 1;
+	}
+
+	/* decode instruction info to get the field to read and where to store
+	 * its value */
+	field = kvm_register_read(vcpu, VMX_OPERAND_REG2(vmx_instruction_info));
+	if (VMX_OPERAND_IS_REG(vmx_instruction_info)) {
+		read_succeed = handle_vmread_reg(vcpu,
+			VMX_OPERAND_REG(vmx_instruction_info), field);
+	} else {
+		gva = get_vmx_mem_address(vcpu, exit_qualification,
+					  vmx_instruction_info);
+		if (gva == 0)
+			return 1;
+		read_succeed = handle_vmread_mem(vcpu, gva, field);
+	}
+
+	if (read_succeed) {
+		clear_rflags_cf_zf(vcpu);
+		skip_emulated_instruction(vcpu);
+	} else {
+		set_rflags_to_vmx_fail_valid(vcpu);
+		vmcs_write32(VM_INSTRUCTION_ERROR, 12);
+	}
+
+	nested_unmap_current(vcpu);
+	return 1;
+}
+
+
+static int handle_vmwrite(struct kvm_vcpu *vcpu)
+{
+	unsigned long field;
+	u64 field_value = 0;
+	gva_t gva;
+	int field_type;
+	unsigned long exit_qualification   = vmcs_readl(EXIT_QUALIFICATION);
+	u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+	char *p;
+	short offset;
+
+	if (!nested_vmx_check_permission(vcpu))
+		return 1;
+
+	if (!nested_map_current(vcpu)) {
+		printk(KERN_INFO "%s invalid shadow vmcs\n", __func__);
+		set_rflags_to_vmx_fail_invalid(vcpu);
+		return 1;
+	}
+
+	field = kvm_register_read(vcpu, VMX_OPERAND_REG2(vmx_instruction_info));
+	field_type = vmcs_field_type(field);
+
+	offset = vmcs_field_to_offset(field);
+	if (offset < 0) {
+		set_rflags_to_vmx_fail_invalid(vcpu);
+		return 1;
+	}
+	p = ((char *) get_shadow_vmcs(vcpu)) + offset;
+
+	if (VMX_OPERAND_IS_REG(vmx_instruction_info))
+		field_value = kvm_register_read(vcpu,
+			VMX_OPERAND_REG(vmx_instruction_info));
+	else {
+		gva  = get_vmx_mem_address(vcpu, exit_qualification,
+			vmx_instruction_info);
+		if (gva == 0)
+			return 1;
+		kvm_read_guest_virt(gva, &field_value,
+			vmcs_field_size(field_type, vcpu), vcpu, NULL);
+	}
+
+	switch (field_type) {
+	case VMCS_FIELD_TYPE_U16:
+		*(u16 *)p = field_value;
+		break;
+	case VMCS_FIELD_TYPE_U32:
+		*(u32 *)p = field_value;
+		break;
+	case VMCS_FIELD_TYPE_U64:
+#ifdef CONFIG_X86_64
+		*(unsigned long *)p = field_value;
+#else
+		*(unsigned long *)p = field_value;
+		*(((unsigned long *)p)+1) = field_value >> 32;
+#endif
+		break;
+	case VMCS_FIELD_TYPE_ULONG:
+		*(unsigned long *)p = field_value;
+		break;
+	default:
+		printk(KERN_INFO "%s invalid field\n", __func__);
+		set_rflags_to_vmx_fail_valid(vcpu);
+		vmcs_write32(VM_INSTRUCTION_ERROR, 12);
+		nested_unmap_current(vcpu);
+		return 1;
+	}
+
+	clear_rflags_cf_zf(vcpu);
+	skip_emulated_instruction(vcpu);
+	nested_unmap_current(vcpu);
+	return 1;
+}
+
 static bool verify_vmcs12_revision(struct kvm_vcpu *vcpu, gpa_t guest_vmcs_addr)
 {
 	bool ret;
@@ -4548,9 +4767,9 @@ static int (*kvm_vmx_exit_handlers[])(st
 	[EXIT_REASON_VMLAUNCH]                = handle_vmx_insn,
 	[EXIT_REASON_VMPTRLD]                 = handle_vmptrld,
 	[EXIT_REASON_VMPTRST]                 = handle_vmptrst,
-	[EXIT_REASON_VMREAD]                  = handle_vmx_insn,
+	[EXIT_REASON_VMREAD]                  = handle_vmread,
 	[EXIT_REASON_VMRESUME]                = handle_vmx_insn,
-	[EXIT_REASON_VMWRITE]                 = handle_vmx_insn,
+	[EXIT_REASON_VMWRITE]                 = handle_vmwrite,
 	[EXIT_REASON_VMOFF]                   = handle_vmoff,
 	[EXIT_REASON_VMON]                    = handle_vmon,
 	[EXIT_REASON_TPR_BELOW_THRESHOLD]     = handle_tpr_below_threshold,
