[PATCH v3 07/20] KVM: VMX: Refactor VMX instruction information access

Chang S. Bae
2026-04-28T05:26:23Z

Introduce a helper that returns the instruction information as 64-bit
value and adjust existing sites to prepare for a wider field.

The VMX instruction information field is currently 32 bits. Future
extensions may expand this field to support extended register IDs,
requiring a wider width. The change provides a single access point for
the transition.

No functional change intended.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
---
V2 -> V3: New patch
---
arch/x86/kvm/vmx/nested.c | 22 +++++++++++-----------
arch/x86/kvm/vmx/nested.h | 2 +-
arch/x86/kvm/vmx/vmx.c | 4 ++--
arch/x86/kvm/vmx/vmx.h | 10 ++++++++--
4 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index c4d2bc080add..69fcbb03ec4b 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5216,7 +5216,7 @@ static void nested_vmx_triple_fault(struct kvm_vcpu *vcpu)
* #UD, #GP, or #SS.
*/
int get_vmx_mem_address(struct kvm_vcpu *vcpu, unsigned long exit_qualification,
- u32 vmx_instruction_info, bool wr, int len, gva_t *ret)
+ u64 vmx_instruction_info, bool wr, int len, gva_t *ret)
{
gva_t off;
bool exn;
@@ -5348,7 +5348,7 @@ static int nested_vmx_get_vmptr(struct kvm_vcpu *vcpu, gpa_t *vmpointer,
int r;

if (get_vmx_mem_address(vcpu, vmx_get_exit_qual(vcpu),
- vmcs_read32(VMX_INSTRUCTION_INFO), false,
+ vmx_get_instr_info(), false,
sizeof(*vmpointer), &gva)) {
*ret = 1;
return -EINVAL;
@@ -5633,7 +5633,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
struct vmcs12 *vmcs12 = is_guest_mode(vcpu) ? get_shadow_vmcs12(vcpu)
: get_vmcs12(vcpu);
unsigned long exit_qualification = vmx_get_exit_qual(vcpu);
- u32 instr_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ u64 instr_info = vmx_get_instr_info();
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct x86_exception e;
unsigned long field;
@@ -5739,7 +5739,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
struct vmcs12 *vmcs12 = is_guest_mode(vcpu) ? get_shadow_vmcs12(vcpu)
: get_vmcs12(vcpu);
unsigned long exit_qualification = vmx_get_exit_qual(vcpu);
- u32 instr_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ u64 instr_info = vmx_get_instr_info();
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct x86_exception e;
unsigned long field;
@@ -5928,7 +5928,7 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
static int handle_vmptrst(struct kvm_vcpu *vcpu)
{
unsigned long exit_qual = vmx_get_exit_qual(vcpu);
- u32 instr_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ u64 instr_info = vmx_get_instr_info();
gpa_t current_vmptr = to_vmx(vcpu)->nested.current_vmptr;
struct x86_exception e;
gva_t gva;
@@ -5956,7 +5956,7 @@ static int handle_vmptrst(struct kvm_vcpu *vcpu)
static int handle_invept(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- u32 vmx_instruction_info, types;
+ u64 vmx_instruction_info, types;
unsigned long type, roots_to_free;
struct kvm_mmu *mmu;
gva_t gva;
@@ -5976,7 +5976,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
if (!nested_vmx_check_permission(vcpu))
return 1;

- vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ vmx_instruction_info = vmx_get_instr_info();
gpr_index = vmx_get_instr_info_reg2(vmx_instruction_info);
type = kvm_register_read(vcpu, gpr_index);

@@ -6036,7 +6036,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
static int handle_invvpid(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- u32 vmx_instruction_info;
+ u64 vmx_instruction_info;
unsigned long type, types;
gva_t gva;
struct x86_exception e;
@@ -6057,7 +6057,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
if (!nested_vmx_check_permission(vcpu))
return 1;

- vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ vmx_instruction_info = vmx_get_instr_info();
gpr_index = vmx_get_instr_info_reg2(vmx_instruction_info);
type = kvm_register_read(vcpu, gpr_index);

@@ -6410,7 +6410,7 @@ static bool nested_vmx_exit_handled_encls(struct kvm_vcpu *vcpu,
static bool nested_vmx_exit_handled_vmcs_access(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12, gpa_t bitmap)
{
- u32 vmx_instruction_info;
+ u64 vmx_instruction_info;
unsigned long field;
u8 b;

@@ -6418,7 +6418,7 @@ static bool nested_vmx_exit_handled_vmcs_access(struct kvm_vcpu *vcpu,
return true;

/* Decode instruction info and find the field to access */
- vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ vmx_instruction_info = vmx_get_instr_info();
field = kvm_register_read(vcpu, (((vmx_instruction_info) >> 28) & 0xf));

/* Out-of-range fields always cause a VM exit from L2 to L1 */
diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
index 213a448104af..ff1ea771d1fb 100644
--- a/arch/x86/kvm/vmx/nested.h
+++ b/arch/x86/kvm/vmx/nested.h
@@ -51,7 +51,7 @@ void nested_sync_vmcs12_to_shadow(struct kvm_vcpu *vcpu);
int vmx_set_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);
int vmx_get_vmx_msr(struct nested_vmx_msrs *msrs, u32 msr_index, u64 *pdata);
int get_vmx_mem_address(struct kvm_vcpu *vcpu, unsigned long exit_qualification,
- u32 vmx_instruction_info, bool wr, int len, gva_t *ret);
+ u64 vmx_instruction_info, bool wr, int len, gva_t *ret);
bool nested_vmx_check_io_bitmaps(struct kvm_vcpu *vcpu, unsigned int port,
int size);

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 05e5005b1524..24e3b47cd1f0 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6119,7 +6119,7 @@ static int handle_monitor_trap(struct kvm_vcpu *vcpu)

static int handle_invpcid(struct kvm_vcpu *vcpu)
{
- u32 vmx_instruction_info;
+ u64 vmx_instruction_info;
unsigned long type;
gva_t gva;
struct {
@@ -6133,7 +6133,7 @@ static int handle_invpcid(struct kvm_vcpu *vcpu)
return 1;
}

- vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
+ vmx_instruction_info = vmx_get_instr_info();
gpr_index = vmx_get_instr_info_reg2(vmx_instruction_info);
type = kvm_register_read(vcpu, gpr_index);

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index da3cdb89a816..280c76af3bb6 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -701,12 +701,18 @@ static inline bool vmx_guest_state_valid(struct kvm_vcpu *vcpu)

void dump_vmcs(struct kvm_vcpu *vcpu);

-static inline int vmx_get_instr_info_reg(u32 vmx_instr_info)
+/* A placeholder to smoothen 64-bit extension */
+static inline u64 vmx_get_instr_info(void)
+{
+ return vmcs_read32(VMX_INSTRUCTION_INFO);
+}
+
+static inline int vmx_get_instr_info_reg(u64 vmx_instr_info)
{
return (vmx_instr_info >> 3) & 0xf;
}

-static inline int vmx_get_instr_info_reg2(u32 vmx_instr_info)
+static inline int vmx_get_instr_info_reg2(u64 vmx_instr_info)
{
return (vmx_instr_info >> 28) & 0xf;
}
--
2.51.0