On 05/09/2013 07:18 PM, Gleb Natapov wrote:
> On Thu, May 09, 2013 at 06:16:55PM +0800, Xiao Guangrong wrote:
>> On 05/09/2013 02:44 PM, Takuya Yoshikawa wrote:
>>> Rather than clearing the ACC_WRITE_MASK bit of pte_access in the
>>> "if (mmu_need_write_protect())" block not to call mark_page_dirty() in
>>> the following if statement, simply moving the call into the appropriate
>>> else block is better.
>>>
>>> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
>>> ---
>>> arch/x86/kvm/mmu.c | 7 ++-----
>>> 1 files changed, 2 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>>> index 004cc87..08119a8 100644
>>> --- a/arch/x86/kvm/mmu.c
>>> +++ b/arch/x86/kvm/mmu.c
>>> @@ -2386,14 +2386,11 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
>>> pgprintk("%s: found shadow page for %llx, marking ro\n",
>>> __func__, gfn);
>>> ret = 1;
>>> - pte_access &= ~ACC_WRITE_MASK;
>>> spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
>>> - }
>>> + } else
>>> + mark_page_dirty(vcpu->kvm, gfn);
>>> }
>>>
>>> - if (pte_access & ACC_WRITE_MASK)
>>> - mark_page_dirty(vcpu->kvm, gfn);
>>> -
>>> set_pte:
>>> if (mmu_spte_update(sptep, spte))
>>> kvm_flush_remote_tlbs(vcpu->kvm);
>>
>> That function is really magic, and this change do no really help it. I had several
>> patches posted some months ago to make these kind of code better understanding, but
>> i am too tired to update them.
> Can you point me to them? Your work is really appreciated, I am sorry
There are two patches about this set_spte cleanups:
https://lkml.org/lkml/2013/1/23/125
https://lkml.org/lkml/2013/1/23/138
> you feel this way.
It is not your fault, it is mine.
Will update these patches when i finish the zap-all-page and zap-mmio-sp
related things.
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