KVM: fix kvm_fix_hypercall() to return X86EMUL_*

This patch fixes kvm_fix_hypercall() to propagate X86EMUL_*
info generated by emulator_write_emulated() to its callers:
suggested by Marcelo.

The effect of this is x86_emulate_insn() will begin to handle
the page faults which occur in emulator_write_emulated():
this should be OK because emulator_write_emulated_onepage()
always injects page fault when emulator_write_emulated()
returns X86EMUL_PROPAGATE_FAULT.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 01f0b037092e..c91007f81660 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3888,10 +3888,8 @@ EXPORT_SYMBOL_GPL(kvm_emulate_hypercall);
 int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
 {
         char instruction[3];
-        int ret = 0;
         unsigned long rip = kvm_rip_read(vcpu);
 
-
         /*
          * Blow out the MMU to ensure that no other VCPU has an active mapping
          * to ensure that the updated hypercall appears atomically across all
@@ -3900,11 +3898,8 @@ int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
         kvm_mmu_zap_all(vcpu->kvm);
 
         kvm_x86_ops->patch_hypercall(vcpu, instruction);
-        if (emulator_write_emulated(rip, instruction, 3, vcpu)
-            != X86EMUL_CONTINUE)
-                ret = -EFAULT;
 
-        return ret;
+        return emulator_write_emulated(rip, instruction, 3, vcpu);
 }
 
 static u64 mk_cr_64(u64 curr_cr, u32 new_val)