Re: [kvm-unit-tests PATCH V3] x86: Add a test to check effective permissions

[Sean Christopherson <seanjc@google.com>]

On Sun, Jun 06, 2021, Lai Jiangshan wrote:
> From: Lai Jiangshan <laijs@linux.alibaba.com>
> 
> Add a test to verify that KVM correctly handles the case where two or
> more non-leaf page table entries point at the same table gfn, but with
> different parent access permissions.
> 
> For example, here is a shared pagetable:
>    pgd[]   pud[]        pmd[]            virtual address pointers
>                      /->pmd1(u--)->pte1(uw-)->page1 <- ptr1 (u--)
>         /->pud1(uw-)--->pmd2(uw-)->pte2(uw-)->page2 <- ptr2 (uw-)
>    pgd-|           (shared pmd[] as above)
>         \->pud2(u--)--->pmd1(u--)->pte1(uw-)->page1 <- ptr3 (u--)
>                      \->pmd2(uw-)->pte2(uw-)->page2 <- ptr4 (u--)
>   pud1 and pud2 point to the same pmd table
> 
> The test is useful when TDP is not enabled.
> 
> Co-Developed-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
> ---

Awesome, thanks!

Reviewed-by: Sean Christopherson <seanjc@google.com>