typo below.
On 6/29/23 13:50, Axel Rasmussen wrote:
> Just describe the feature at a really basic level.
>
> Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
> ---
> Documentation/admin-guide/mm/userfaultfd.rst | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst
> index 7c304e432205..b19053436369 100644
> --- a/Documentation/admin-guide/mm/userfaultfd.rst
> +++ b/Documentation/admin-guide/mm/userfaultfd.rst
> @@ -244,6 +244,21 @@ write-protected (so future writes will also result in a WP fault). These ioctls
> support a mode flag (``UFFDIO_COPY_MODE_WP`` or ``UFFDIO_CONTINUE_MODE_WP``
> respectively) to configure the mapping this way.
>
> +Memory Poisioning Emulation
> +---------------------------
> +
> +In response to a fault (either missing or minor), an action userspace can
> +take to "resolve" it is to issue a ``UFFDIO_POISON``. This will cause any
> +future faulters to either get a SIGBUS, or in KVM's case the guest will
> +receive an MCE as if there were hardware memory poisoning.
> +
> +This is used to emulate hardware memory poisoning. Imagine a VM running on a
> +machine which experiences a real hardware memory error. Later, we live migrate
> +the VM to another physical machine. Since we want the migration to be
> +transparent to the guest, we want that same address range to act as if it was
> +still poisoned, even though it's on a new physical host which ostentisbly
ostensibly
> +doesn't have a memory error in the exact same spot.
> +
> QEMU/KVM
> ========
>
--
~Randy
