Re: [PATCH v3 10/15] KVM: MMU: allocate shadow pages from slab

Xiao Guangrong
2013-10-24T10:10:56Z

On 10/24/2013 05:52 PM, Gleb Natapov wrote:
> On Thu, Oct 24, 2013 at 05:29:44PM +0800, Xiao Guangrong wrote:
>> On 10/24/2013 05:19 PM, Gleb Natapov wrote:
>>
>>>> @@ -946,7 +947,7 @@ static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
>>>> {
>>>> struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT);
>>>>
>>>> - return (struct kvm_mmu_page *)page_private(page);
>>>> + return (struct kvm_mmu_page *)(page->mapping);
>>> Why?
>>
>> That's because page->private has been used by slab:
>>
> But does lockless path actually looks at it?

Lockless path does not use it, however, it is used by kvm_mmu_page():

static inline struct kvm_mmu_page *page_header(hpa_t shadow_page)
{
struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT);

return (struct kvm_mmu_page *)(page->mapping);
}

which is used in the common code.