[PATCH v2] KVM: VMX: Remove the unused variable "gpa" in __invept()

[PATCH v2] KVM: VMX: Remove the unused variable "gpa" in __invept()

[Yan Zhao]

Remove the unused variable "gpa" in __invept().

The INVEPT instruction only supports two types: VMX_EPT_EXTENT_CONTEXT (1)
and VMX_EPT_EXTENT_GLOBAL (2). Neither of these types requires a third
variable "gpa".

The "gpa" variable for __invept() is always set to 0 and was originally
introduced for the old non-existent type VMX_EPT_EXTENT_INDIVIDUAL_ADDR
(0). This type was removed by commit 2b3c5cbc0d81 ("kvm: don't use bit24
for detecting address-specific invalidation capability") and
commit 63f3ac48133a ("KVM: VMX: clean up declaration of VPID/EPT
invalidation types").

Since this variable is not useful for error handling either, remove it to
avoid confusion.

No functional changes expected.

Cc: Yuan Yao <yuan.yao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
--
v2:
Add the missing must_be_zero 64 bits.
---
 arch/x86/kvm/vmx/vmx.c     |  5 ++---
 arch/x86/kvm/vmx/vmx_ops.h | 16 ++++++++--------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1a4438358c5e..c0f4bb506a58 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -481,10 +481,9 @@ noinline void invvpid_error(unsigned long ext, u16 vpid, gva_t gva)
 			ext, vpid, gva);
 }
 
-noinline void invept_error(unsigned long ext, u64 eptp, gpa_t gpa)
+noinline void invept_error(unsigned long ext, u64 eptp)
 {
-	vmx_insn_failed("invept failed: ext=0x%lx eptp=%llx gpa=0x%llx\n",
-			ext, eptp, gpa);
+	vmx_insn_failed("invept failed: ext=0x%lx eptp=%llx\n", ext, eptp);
 }
 
 static DEFINE_PER_CPU(struct vmcs *, vmxarea);
diff --git a/arch/x86/kvm/vmx/vmx_ops.h b/arch/x86/kvm/vmx/vmx_ops.h
index 93e020dc88f6..633c87e2fd92 100644
--- a/arch/x86/kvm/vmx/vmx_ops.h
+++ b/arch/x86/kvm/vmx/vmx_ops.h
@@ -15,7 +15,7 @@ void vmwrite_error(unsigned long field, unsigned long value);
 void vmclear_error(struct vmcs *vmcs, u64 phys_addr);
 void vmptrld_error(struct vmcs *vmcs, u64 phys_addr);
 void invvpid_error(unsigned long ext, u16 vpid, gva_t gva);
-void invept_error(unsigned long ext, u64 eptp, gpa_t gpa);
+void invept_error(unsigned long ext, u64 eptp);
 
 #ifndef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
 /*
@@ -312,13 +312,13 @@ static inline void __invvpid(unsigned long ext, u16 vpid, gva_t gva)
 	vmx_asm2(invvpid, "r"(ext), "m"(operand), ext, vpid, gva);
 }
 
-static inline void __invept(unsigned long ext, u64 eptp, gpa_t gpa)
+static inline void __invept(unsigned long ext, u64 eptp)
 {
 	struct {
-		u64 eptp, gpa;
-	} operand = {eptp, gpa};
-
-	vmx_asm2(invept, "r"(ext), "m"(operand), ext, eptp, gpa);
+		u64 eptp;
+		u64 reserved_0;
+	} operand = { eptp, 0 };
+	vmx_asm2(invept, "r"(ext), "m"(operand), ext, eptp);
 }
 
 static inline void vpid_sync_vcpu_single(int vpid)
@@ -355,13 +355,13 @@ static inline void vpid_sync_vcpu_addr(int vpid, gva_t addr)
 
 static inline void ept_sync_global(void)
 {
-	__invept(VMX_EPT_EXTENT_GLOBAL, 0, 0);
+	__invept(VMX_EPT_EXTENT_GLOBAL, 0);
 }
 
 static inline void ept_sync_context(u64 eptp)
 {
 	if (cpu_has_vmx_invept_context())
-		__invept(VMX_EPT_EXTENT_CONTEXT, eptp, 0);
+		__invept(VMX_EPT_EXTENT_CONTEXT, eptp);
 	else
 		ept_sync_global();
 }

base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b
-- 
2.43.2

Re: [PATCH v2] KVM: VMX: Remove the unused variable "gpa" in __invept()

[Sean Christopherson]

On Mon, 14 Oct 2024 12:59:31 +0800, Yan Zhao wrote:
> Remove the unused variable "gpa" in __invept().
> 
> The INVEPT instruction only supports two types: VMX_EPT_EXTENT_CONTEXT (1)
> and VMX_EPT_EXTENT_GLOBAL (2). Neither of these types requires a third
> variable "gpa".
> 
> The "gpa" variable for __invept() is always set to 0 and was originally
> introduced for the old non-existent type VMX_EPT_EXTENT_INDIVIDUAL_ADDR
> (0). This type was removed by commit 2b3c5cbc0d81 ("kvm: don't use bit24
> for detecting address-specific invalidation capability") and
> commit 63f3ac48133a ("KVM: VMX: clean up declaration of VPID/EPT
> invalidation types").
> 
> [...]

Applied to kvm-x86 vmx, thanks!

[1/1] KVM: VMX: Remove the unused variable "gpa" in __invept()
      https://github.com/kvm-x86/linux/commit/bc17fccb37c8

--
https://github.com/kvm-x86/linux/tree/next