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

[Peter Maydell]

On Fri, 5 Feb 2021 at 13:58, Steven Price <steven.price@arm.com> 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@arm.com>
> ---
>  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 :-)

thanks
-- PMM