Re: [RFC PATCH v8 5/5] KVM: arm64: ioctl to fetch/store tags in a guest

[Steven Price]

On 08/02/2021 17:31, Peter Maydell wrote:
> On Fri, 5 Feb 2021 at 13:58, Steven Price <steven.price@xxxxxxx> wrote:
> > The VMM may not wish to have it's own mapping of guest memory mapped
> > with PROT_MTE because this causes problems if the VMM has tag checking
> > enabled (the guest controls the tags in physical RAM and it's unlikely
> > the tags are correct for the VMM).
> >
> > Instead add a new ioctl which allows the VMM to easily read/write the
> > tags from guest memory, allowing the VMM's mapping to be non-PROT_MTE
> > while the VMM can still read/write the tags for the purpose of
> > migration.
> >
> > Signed-off-by: Steven Price <steven.price@xxxxxxx>
> > ---
> >   arch/arm64/include/uapi/asm/kvm.h | 13 +++++++
> >   arch/arm64/kvm/arm.c              | 57 +++++++++++++++++++++++++++++++
> >   include/uapi/linux/kvm.h          |  1 +
> >   3 files changed, 71 insertions(+)
>
> Missing the update to the docs in Documentation/virtual/kvm/api.txt :-)

Good point - although I was secretly hoping to get some feedback on the 
concepts before writing the documentation! But I guess the documentation 
will help with the review. I'll include some in the next posting.

Thanks,

Steve