linux-kernel - [PATCH 32/38] KVM: fix kvm_fix_hypercall() to return X86EMUL

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Date:	Tue, 16 Feb 2010 12:35:30 +0200
From:	Avi Kivity <avi@...hat.com>
To:	kvm@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH 32/38] KVM: fix kvm_fix_hypercall() to return X86EMUL_*

From: Takuya Yoshikawa <yoshikawa.takuya@....ntt.co.jp>

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@....ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com>
---
 arch/x86/kvm/x86.c |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 01f0b03..c91007f 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)
-- 
1.6.5.3

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