KVM: x86: Fold retry_instruction() into x86_emulate_instruction()

Now that retry_instruction() is reasonably tiny, fold it into its sole
caller, x86_emulate_instruction().  In addition to getting rid of the
absurdly confusing retry_instruction() name, handling the retry in
x86_emulate_instruction() pairs it back up with the code that resets
last_retry_{eip,address}.

No functional change intended.

Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20240831001538.336683-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 51d22d9..a7961f8 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8924,26 +8924,6 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
        return !(emulation_type & EMULTYPE_WRITE_PF_TO_SP);
 }
 
-static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
-                             gpa_t cr2_or_gpa,  int emulation_type)
-{
-       struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
-
-       /*
-        * If the emulation is caused by #PF and it is non-page_table
-        * writing instruction, it means the VM-EXIT is caused by shadow
-        * page protected, we can zap the shadow page and retry this
-        * instruction directly.
-        */
-       if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF))
-               return false;
-
-       if (x86_page_table_writing_insn(ctxt))
-               return false;
-
-       return kvm_mmu_unprotect_gfn_and_retry(vcpu, cr2_or_gpa);
-}
-
 static int complete_emulated_mmio(struct kvm_vcpu *vcpu);
 static int complete_emulated_pio(struct kvm_vcpu *vcpu);
 
@@ -9223,7 +9203,15 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
                return 1;
        }
 
-       if (retry_instruction(ctxt, cr2_or_gpa, emulation_type))
+       /*
+        * If emulation was caused by a write-protection #PF on a non-page_table
+        * writing instruction, try to unprotect the gfn, i.e. zap shadow pages,
+        * and retry the instruction, as the vCPU is likely no longer using the
+        * gfn as a page table.
+        */
+       if ((emulation_type & EMULTYPE_ALLOW_RETRY_PF) &&
+           !x86_page_table_writing_insn(ctxt) &&
+           kvm_mmu_unprotect_gfn_and_retry(vcpu, cr2_or_gpa))
                return 1;
 
        /* this is needed for vmware backdoor interface to work since it