On 11/21/2012 06:27 AM, Marcelo Tosatti wrote:
>> @@ -544,6 +544,21 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu,
>> gva_t addr, u32 error_code,
>> return 0;
>> }
>>
>> + if (write_fault && !(walker.pte_access & ACC_WRITE_MASK) &&
>> + !is_write_protection(vcpu) && !user_fault) {
>> + walker.pte_access |= ACC_WRITE_MASK;
>> + walker.pte_access &= ~ACC_USER_MASK;
>> +
>> + /*
>> + * If we converted a user page to a kernel page,
>> + * so that the kernel can write to it when cr0.wp=0,
>> + * then we should prevent the kernel from executing it
>> + * if SMEP is enabled.
>> + */
>> + if (kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
>> + walker.pte_access &= ~ACC_EXEC_MASK;
>> + }
>> +
>
> What about sync_page path?
The sync_page and other prefetch paths only do read-prefetch, means
they call set_spte with write_fault = 0.
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