Re: [PATCH v2 21/27] docs: kvm: Convert locking.txt to ReST format

[Cornelia Huck <cohuck@redhat.com>]

On Thu,  6 Feb 2020 15:50:18 +0100
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:

> - Use document title and chapter markups;
> - Add markups for literal blocks;
> - use :field: for field descriptions;
> - Add blank lines and adjust indentation.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> ---
>  Documentation/virt/kvm/index.rst              |   1 +
>  .../virt/kvm/{locking.txt => locking.rst}     | 111 ++++++++++--------
>  2 files changed, 63 insertions(+), 49 deletions(-)
>  rename Documentation/virt/kvm/{locking.txt => locking.rst} (78%)

(...)

> @@ -48,19 +52,23 @@ restore the saved R/X bits if VMX_EPT_TRACK_ACCESS mask is set, or both. This
>  is safe because whenever changing these bits can be detected by cmpxchg.
>  
>  But we need carefully check these cases:
> -1): The mapping from gfn to pfn
> +
> +1) The mapping from gfn to pfn
> +
>  The mapping from gfn to pfn may be changed since we can only ensure the pfn
>  is not changed during cmpxchg. This is a ABA problem, for example, below case
>  will happen:
>  
> -At the beginning:
> -gpte = gfn1
> -gfn1 is mapped to pfn1 on host
> -spte is the shadow page table entry corresponding with gpte and
> -spte = pfn1
> +At the beginning::
>  
> -   VCPU 0                           VCPU0
> -on fast page fault path:
> +	gpte = gfn1
> +	gfn1 is mapped to pfn1 on host
> +	spte is the shadow page table entry corresponding with gpte and
> +	spte = pfn1
> +
> +	   VCPU 0                           VCPU0
> +
> +on fast page fault path::
>  
>     old_spte = *spte;
>                                   pfn1 is swapped out:

I'm wondering if that should rather be converted to a proper table.

(...)

> @@ -99,12 +109,14 @@ Accessed bit and Dirty bit can not be lost.
>  But it is not true after fast page fault since the spte can be marked
>  writable between reading spte and updating spte. Like below case:
>  
> -At the beginning:
> -spte.W = 0
> -spte.Accessed = 1
> +At the beginning::
>  
> -   VCPU 0                                       VCPU0
> -In mmu_spte_clear_track_bits():
> +	spte.W = 0
> +	spte.Accessed = 1
> +
> +	   VCPU 0                                       VCPU0
> +
> +In mmu_spte_clear_track_bits()::
>  
>     old_spte = *spte;
>  

This one as well.