Commit 2634b997af ("x86/shadow: don't enable shadow mode with too small
a shadow allocation") was incomplete: The adjustment done there to
shadow_enable() is also needed in shadow_one_bit_enable(). The (new)
problem report was (apparently) a failed PV guest migration followed by
another migration attempt for that same guest. Disabling log-dirty mode
after the first one had left a couple of shadow pages allocated (perhaps
something that also wants fixing), and hence the second enabling of
log-dirty mode wouldn't have allocated anything further.
Reported-by: James Wang <jnw...@suse.com>
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -2864,7 +2864,8 @@ static int shadow_one_bit_enable(struct
mode |= PG_SH_enable;
- if ( d->arch.paging.shadow.total_pages == 0 )
+ if ( d->arch.paging.shadow.total_pages <
+ sh_min_allocation(d) + d->arch.paging.shadow.p2m_pages )
{
/* Init the shadow memory allocation if the user hasn't done so */
if ( shadow_set_allocation(d, 1, NULL) != 0 )
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