Allowing x86_emulate_instruction() to be called directly has led to
subtle bugs being introduced, e.g. not setting EMULTYPE_NO_REEXECUTE
in the emulation type. While most of the blame lies on re-execute
being opt-out, exporting x86_emulate_instruction() also exposes its
cr2 parameter, which may have contributed to commit d391f1207067
("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO
when running nested") using x86_emulate_instruction() instead of
emulate_instruction() because "hey, I have a cr2!", which in turn
introduced its EMULTYPE_NO_REEXECUTE bug.
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 17 +++--------------
arch/x86/kvm/x86.c | 14 +++++++++++++-
arch/x86/kvm/x86.h | 2 ++
3 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8c9023661351..e12916e7c2fb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1240,20 +1240,9 @@ enum emulation_result {
#define EMULTYPE_ALLOW_RETRY (1 << 3)
#define EMULTYPE_NO_UD_ON_FAIL (1 << 4)
#define EMULTYPE_VMWARE (1 << 5)
-int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
- int emulation_type, void *insn, int insn_len);
-
-static inline int kvm_emulate_instruction(struct kvm_vcpu *vcpu,
- int emulation_type)
-{
- return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);
-}
-
-static inline int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
- void *insn, int insn_len)
-{
- return x86_emulate_instruction(vcpu, 0, 0, insn, insn_len);
-}
+int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type);
+int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
+ void *insn, int insn_len);
void kvm_enable_efer_bits(u64);
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6b5a74629340..e4e873d36ed5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6282,7 +6282,19 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
return r;
}
-EXPORT_SYMBOL_GPL(x86_emulate_instruction);
+
+int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type)
+{
+ return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(kvm_emulate_instruction);
+
+int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
+ void *insn, int insn_len)
+{
+ return x86_emulate_instruction(vcpu, 0, 0, insn, insn_len);
+}
+EXPORT_SYMBOL_GPL(kvm_emulate_instruction_from_buffer);
static int kvm_fast_pio_out(struct kvm_vcpu *vcpu, int size,
unsigned short port)
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 257f27620bc2..67b9568613f3 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -274,6 +274,8 @@ int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata);
bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
int page_num);
bool kvm_vector_hashing_enabled(void);
+int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
+ int emulation_type, void *insn, int insn_len);
#define KVM_SUPPORTED_XCR0 (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \
| XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
--
2.18.0
