[PATCH 1/4] nested vmx: clean up for vmcs12 read and write

[Dongxiao Xu <dongxiao.xu@xxxxxxxxx>]

abstract vmcs12_read and vmcs12_write functions to do the vmcs12
read/write operations.

Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
---
 arch/x86/kvm/vmx.c |   86 +++++++++++++++++++++++++++-------------------------
 1 files changed, 45 insertions(+), 41 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f858159..d8670e4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5407,32 +5407,67 @@ static inline int vmcs_field_readonly(unsigned long field)
  * some of the bits we return here (e.g., on 32-bit guests, only 32 bits of
  * 64-bit fields are to be returned).
  */
-static inline bool vmcs12_read_any(struct kvm_vcpu *vcpu,
-					unsigned long field, u64 *ret)
+static inline u64 vmcs12_read(struct kvm_vcpu *vcpu, unsigned long field)
 {
 	short offset = vmcs_field_to_offset(field);
 	char *p;
 
-	if (offset < 0)
+	if (offset < 0) {
+		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
+		skip_emulated_instruction(vcpu);
 		return 0;
+	}
 
 	p = ((char *)(get_vmcs12(vcpu))) + offset;
 
 	switch (vmcs_field_type(field)) {
 	case VMCS_FIELD_TYPE_NATURAL_WIDTH:
-		*ret = *((natural_width *)p);
+		return *((natural_width *)p);
+	case VMCS_FIELD_TYPE_U16:
+		return *((u16 *)p);
+	case VMCS_FIELD_TYPE_U32:
+		return *((u32 *)p);
+	case VMCS_FIELD_TYPE_U64:
+		return *((u64 *)p);
+	default:
+		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
+		skip_emulated_instruction(vcpu);
+		return 0; /* can never happen. */
+	}
+}
+
+static inline int vmcs12_write(struct kvm_vcpu *vcpu,
+			unsigned long field,
+			u64 value)
+{
+	short offset = vmcs_field_to_offset(field);
+	char *p;
+
+	if (offset < 0) {
+		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
+		skip_emulated_instruction(vcpu);
+		return 0;
+	}
+
+	p = ((char *)(get_vmcs12(vcpu))) + offset;
+
+	switch (vmcs_field_type(field)) {
+	case VMCS_FIELD_TYPE_NATURAL_WIDTH:
+		*(natural_width *)p = value;
 		return 1;
 	case VMCS_FIELD_TYPE_U16:
-		*ret = *((u16 *)p);
+		*(u16 *)p = value;
 		return 1;
 	case VMCS_FIELD_TYPE_U32:
-		*ret = *((u32 *)p);
+		*(u32 *)p = value;
 		return 1;
 	case VMCS_FIELD_TYPE_U64:
-		*ret = *((u64 *)p);
+		*(u64 *)p = value;
 		return 1;
 	default:
-		return 0; /* can never happen. */
+		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
+		skip_emulated_instruction(vcpu);
+		return 0;
 	}
 }
 
@@ -5466,11 +5501,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
 	/* Decode instruction info and find the field to read */
 	field = kvm_register_read(vcpu, (((vmx_instruction_info) >> 28) & 0xf));
 	/* Read the field, zero-extended to a u64 field_value */
-	if (!vmcs12_read_any(vcpu, field, &field_value)) {
-		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
-		skip_emulated_instruction(vcpu);
-		return 1;
-	}
+	field_value = vmcs12_read(vcpu, field);
 	/*
 	 * Now copy part of this value to register or memory, as requested.
 	 * Note that the number of bits actually copied is 32 or 64 depending
@@ -5500,8 +5531,6 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
 	gva_t gva;
 	unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
 	u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
-	char *p;
-	short offset;
 	/* The value to write might be 32 or 64 bits, depending on L1's long
 	 * mode, and eventually we need to write that into a field of several
 	 * possible lengths. The code below first zero-extends the value to 64
@@ -5537,33 +5566,8 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
 		skip_emulated_instruction(vcpu);
 		return 1;
 	}
-
-	offset = vmcs_field_to_offset(field);
-	if (offset < 0) {
-		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
-		skip_emulated_instruction(vcpu);
-		return 1;
-	}
-	p = ((char *) get_vmcs12(vcpu)) + offset;
-
-	switch (vmcs_field_type(field)) {
-	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:
-		*(u64 *)p = field_value;
-		break;
-	case VMCS_FIELD_TYPE_NATURAL_WIDTH:
-		*(natural_width *)p = field_value;
-		break;
-	default:
-		nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
-		skip_emulated_instruction(vcpu);
+	if (!vmcs12_write(vcpu, field, field_value))
 		return 1;
-	}
 
 	nested_vmx_succeed(vcpu);
 	skip_emulated_instruction(vcpu);
-- 
1.7.1

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