Re: [PATCH v1 1/1] migration: prevent migration when VM has poisoned memory

[Peter Xu <peterx@redhat.com>]

On Tue, Jan 30, 2024 at 07:06:40PM +0000, “William Roche wrote:
> From: William Roche <william.roche@oracle.com>
> 
> A memory page poisoned from the hypervisor level is no longer readable.
> The migration of a VM will crash Qemu when it tries to read the
> memory address space and stumbles on the poisoned page with a similar
> stack trace:
> 
> Program terminated with signal SIGBUS, Bus error.
> #0  _mm256_loadu_si256
> #1  buffer_zero_avx2
> #2  select_accel_fn
> #3  buffer_is_zero
> #4  save_zero_page
> #5  ram_save_target_page_legacy
> #6  ram_save_host_page
> #7  ram_find_and_save_block
> #8  ram_save_iterate
> #9  qemu_savevm_state_iterate
> #10 migration_iteration_run
> #11 migration_thread
> #12 qemu_thread_start
> 
> To avoid this VM crash during the migration, prevent the migration
> when a known hardware poison exists on the VM.
> 
> Signed-off-by: William Roche <william.roche@oracle.com>

I queued it for now, while it'll always good to get feedback from either
Paolo or anyone else, as the pull won't happen in one week.  If no
objection it'll be included the next migration pull.

Thanks,

-- 
Peter Xu