Re: [RFC PATCH 0/5] target/arm: Add MTE support to KVM guest

[Peter Maydell]

Adding the migration maintainers to the cc list, because
the real meat of this patchset is "how should the migration
of MTE tags be integrated into the migration/ram.c code",
which is pretty well out of my area of expertise...

thanks
-- PMM

On Mon, 8 Feb 2021 at 03:20, Haibo Xu <haibo.xu@linaro.org> wrote:
>
> This series add support for MTE(Memory Tagging Extension)[1]
> in KVM guest. It's based on Steven Price's kernel KVM patches
> V7[2], and has been tested to ensure that test case[3] can be
> passed in a KVM guest. Basic pre-copy migration test also passed
> between two MTE enabled kvm guest.
>
> This is a RFC patch series becuase:
> (1) Need to add some arm MTE specific codes to the ram migration
>     loop. There may be better way to do that in a more abstract way.
> (2) Only pre-copy migration is supported and tested currently,
>     post-copy as well as compress/zero page migration are still WIP.
>
> All kinds of feedbacks are very welcomed, especially for the migration
> support.
>
> Note:
> (1) To support MTE migration, tags for one page are appended to
>     the page data during ram save iteration which make it easier
>     to sync the page data and tags.
>
> [1] https://community.arm.com/developer/ip-products/processors/b/
>     processors-ip-blog/posts/enhancing-memory-safety
> [2] https://lwn.net/Articles/842827/
> [3] https://elixir.bootlin.com/linux/latest/source/Documentation/
>     arm64/memory-tagging-extension.rst
>
> Haibo Xu (5):
>   Update Linux headers with new MTE support
>   Add basic MTE support to KVM guest
>   Add APIs to get/set MTE tags
>   Add migration support for KVM guest with MTE
>   Enable the MTE support for KVM guest
>
>  hw/arm/virt.c             | 44 +++++++++++++-------
>  include/hw/arm/virt.h     |  2 +
>  include/migration/misc.h  |  1 +
>  linux-headers/linux/kvm.h | 15 +++++++
>  migration/ram.c           | 86 ++++++++++++++++++++++++++++++++++++++-
>  target/arm/cpu.c          |  2 +-
>  target/arm/kvm.c          |  9 ++++
>  target/arm/kvm64.c        | 31 ++++++++++++++
>  target/arm/kvm_arm.h      |  2 +
>  9 files changed, 176 insertions(+), 16 deletions(-)