Re: [PATCH 4/6] KVM: Documentation: Add the missing tdp_mmu_root_count into kvm_mmu_page

[Huang, Kai]

On Sun, 2023-06-18 at 00:08 +0000, Mingwei Zhang wrote:
> Add tdp_mmu_root_count into kvm_mmu_page description. tdp_mmu_root_count is
> an atomic counter used only in TDP MMU. Its usage and meaning is slightly
> different with root_counter in shadow MMU. Update the doc.
> 
> Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
> ---
>  Documentation/virt/kvm/x86/mmu.rst | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst
> index 36bfe0fe02bb..3dce2426ad6d 100644
> --- a/Documentation/virt/kvm/x86/mmu.rst
> +++ b/Documentation/virt/kvm/x86/mmu.rst
> @@ -230,6 +230,12 @@ Shadow pages contain the following information:
>      A counter keeping track of how many hardware registers (guest cr3 or
>      pdptrs) are now pointing at the page.  While this counter is nonzero, the
>      page cannot be destroyed.  See role.invalid.
> +  tdp_mmu_root_count:
> +    An atomic reference counter in TDP MMU that allows for parallel
					     ^
Please explicitly say "TDP MMU root page" ?
			
> +    accesses.  Accessing the page requires lifting the counter value. The
> +    initial value is set as 2 indicating one reference from vCPU and one
			    ^
			    to ?

> +    from TDP MMU itself. 
> 


> While this counter is nonzero, the page cannot be
> +    destroyed. 
> 

I guess this sentence is implied by "reference counter" mentioned in the first
sentence.

> Note this field is a union with root_count.
>