Re: [PATCH] db/leaf_8000000a: Add Page modification logging

Hi,

On Mon, 11 Aug 2025, Nikunj A Dadhania wrote:
>
> Page modification logging(PML) is hardware feature designed to track
> guest modified memory pages. PML enables the hypervisor to identify
> which pages in a guest's memory have been changed since the last
> checkpoint or during live migration.
>
> Signed-off-by: Nikunj A Dadhania <[email protected]>
> ---
>  db/xml/leaf_8000000a.xml | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/db/xml/leaf_8000000a.xml b/db/xml/leaf_8000000a.xml
> index 7f73318..433c4b1 100644
> --- a/db/xml/leaf_8000000a.xml
> +++ b/db/xml/leaf_8000000a.xml
> @@ -14,6 +14,11 @@
>      <ebx>
>        <bit0  len="32" id="svm_nasid"               desc="Number of address space identifiers (ASID)" />
>      </ebx>
> +    <ecx>
> +      <bit4  len="1"  id="pml"                     desc="Page modification logging (PML)">
> +        <linux        feature="true"               proc="false" />
> +      </bit4>
> +    </ecx>
>

Thanks a lot for the patch.

feature="true" means that the Linux kernel will have an X86_FEATURE_PML
flag at some point.  I've quickly searched LKML, and I didn't find any
draft patches for such a flag.

If that feature flag is not planned, there's no need to send a v2.  I'll
just set feature="false" before merging to tip.

Thanks!

--
Ahmed S. Darwish
Linutronix GmbH