From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] KVM: MMU: fix permission_fault()
Date: Fri, 25 Mar 2016 21:41:59 +0800 [thread overview]
Message-ID: <56F54027.3050001@linux.intel.com> (raw)
In-Reply-To: <56F53E87.6010304@redhat.com>
On 03/25/2016 09:35 PM, Paolo Bonzini wrote:
>
>
> On 25/03/2016 14:19, Xiao Guangrong wrote:
>> kvm-unit-tests complained about the PFEC is not set properly, e.g,:
>> test pte.rw pte.d pte.nx pde.p pde.rw pde.pse user fetch: FAIL: error code 15
>> expected 5
>> Dump mapping: address: 0x123400000000
>> ------L4: 3e95007
>> ------L3: 3e96007
>> ------L2: 2000083
>
> What's the command line for the reproducer?
QEMU=/home/eric/qemu/x86_64-softmmu/qemu-system-x86_64 ./x86-run x86/access.flat
>
>> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
>> index b70df72..81bffd1 100644
>> --- a/arch/x86/kvm/mmu.h
>> +++ b/arch/x86/kvm/mmu.h
>> @@ -154,7 +154,7 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
>> unsigned pfec)
>> {
>> int cpl = kvm_x86_ops->get_cpl(vcpu);
>> - unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
>> + unsigned long errcode, rflags = kvm_x86_ops->get_rflags(vcpu);
>>
>> /*
>> * If CPL < 3, SMAP prevention are disabled if EFLAGS.AC = 1.
>> @@ -175,7 +175,7 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
>> bool fault = (mmu->permissions[index] >> pte_access) & 1;
>>
>> WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK));
>> - pfec |= PFERR_PRESENT_MASK;
>> + errcode = PFERR_PRESENT_MASK;
>
> So is this patch doing the same as "KVM: MMU: precompute page fault
> error code"? It was necessary after all. :)
Sorry for my mistake... I missed the logic you changed :(
I still prefer to calculating the error code on the fault path which is rare, or
think a way to encapsulate it to permission_fault()...
next prev parent reply other threads:[~2016-03-25 13:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-25 13:19 [PATCH 1/4] KVM: MMU: fix permission_fault() Xiao Guangrong
2016-03-25 13:19 ` [PATCH 2/4] KVM: MMU: simplify the logic of __mmu_unsync_walk() Xiao Guangrong
2016-03-25 13:19 ` [PATCH 3/4] KVM: MMU: reduce the size of mmu_page_path Xiao Guangrong
2016-03-25 13:45 ` Paolo Bonzini
2016-03-25 13:48 ` Xiao Guangrong
2016-03-25 13:56 ` Paolo Bonzini
2016-03-25 14:07 ` Xiao Guangrong
2016-03-25 14:22 ` Paolo Bonzini
2016-03-25 13:19 ` [PATCH 4/4] KVM: MMU: skip obsolete sp in for_each_gfn_*() Xiao Guangrong
2016-03-29 9:44 ` Paolo Bonzini
2016-03-25 13:35 ` [PATCH 1/4] KVM: MMU: fix permission_fault() Paolo Bonzini
2016-03-25 13:41 ` Xiao Guangrong [this message]
2016-03-25 13:50 ` Paolo Bonzini
2016-03-25 14:21 ` Paolo Bonzini
2016-03-29 17:43 ` Xiao Guangrong
2016-03-29 20:09 ` Paolo Bonzini
2016-03-30 1:56 ` Xiao Guangrong
2016-03-30 6:36 ` Paolo Bonzini
2016-03-30 6:39 ` Xiao Guangrong
2016-04-06 3:27 ` Xiao Guangrong
2016-04-06 8:17 ` Paolo Bonzini
2016-04-06 8:56 ` Paolo Bonzini
2016-04-06 15:09 ` Xiao Guangrong
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