Re: [PATCH 1/3] KVM: x86: clean up reexecute_instruction

From: Xiao Guangrong
Date: Tue Nov 20 2012 - 15:13:00 EST


On 11/20/2012 08:11 PM, Gleb Natapov wrote:
> On Tue, Nov 20, 2012 at 07:58:32AM +0800, Xiao Guangrong wrote:
>> Little cleanup for reexecute_instruction, also use gpa_to_gfn in
>> retry_instruction
>>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
>> ---
>> arch/x86/kvm/x86.c | 13 ++++++-------
>> 1 files changed, 6 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 52ae8b5..7be8452 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -4477,19 +4477,18 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva)
>> if (tdp_enabled)
>> return false;
>>
>> + gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
>> + if (gpa == UNMAPPED_GVA)
>> + return true; /* let cpu generate fault */
>> +
>> /*
>> * if emulation was due to access to shadowed page table
>> * and it failed try to unshadow page and re-enter the
>> * guest to let CPU execute the instruction.
>> */
>> - if (kvm_mmu_unprotect_page_virt(vcpu, gva))
>> + if (kvm_mmu_unprotect_page(vcpu->kvm, c(gpa)))
> What's c()? Should be gpa_to_gfn(gpa)?

Yes. It is the stupid copy-paste error. Thanks you for pointing it out, Gleb!
This is the new one have fixed it.

Subject: [PATCH 1/3] KVM: x86: clean up reexecute_instruction

Little cleanup for reexecute_instruction, also use gpa_to_gfn in
retry_instruction

Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 13 ++++++-------
1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 52ae8b5..7be8452 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4477,19 +4477,18 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t gva)
if (tdp_enabled)
return false;

+ gpa = kvm_mmu_gva_to_gpa_read(vcpu, gva, NULL);
+ if (gpa == UNMAPPED_GVA)
+ return true; /* let cpu generate fault */
+
/*
* if emulation was due to access to shadowed page table
* and it failed try to unshadow page and re-enter the
* guest to let CPU execute the instruction.
*/
- if (kvm_mmu_unprotect_page_virt(vcpu, gva))
+ if (kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa)))
return true;

- gpa = kvm_mmu_gva_to_gpa_system(vcpu, gva, NULL);
-
- if (gpa == UNMAPPED_GVA)
- return true; /* let cpu generate fault */
-
/*
* Do not retry the unhandleable instruction if it faults on the
* readonly host memory, otherwise it will goto a infinite loop:
@@ -4544,7 +4543,7 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
if (!vcpu->arch.mmu.direct_map)
gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2, NULL);

- kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
+ kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa));

return true;
}
--
1.7.7.6


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