58 lines
2.1 KiB
Diff
58 lines
2.1 KiB
Diff
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# HG changeset patch
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# Parent 00989d5f44b59ba7f3a467342a14b9c7621fa926
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xenpaging: restore p2mt if gfn is needed before evict
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In the rare case that a gfn is needed by a guest or a foreign domain
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between nominate and evict, restore the p2mt and skip sending a request.
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A request is not needed because the pager will notice the evict failure.
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Signed-off-by: Olaf Hering <olaf@aepfle.de>
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---
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xen/arch/x86/mm/p2m.c | 18 +++++++++++-------
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1 file changed, 11 insertions(+), 7 deletions(-)
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--- a/xen/arch/x86/mm/p2m.c
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+++ b/xen/arch/x86/mm/p2m.c
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@@ -3036,6 +3036,7 @@ void p2m_mem_paging_populate(struct p2m_
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p2m_type_t p2mt;
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p2m_access_t a;
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mfn_t mfn;
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+ int restored = 0;
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struct domain *d = p2m->domain;
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/* Check that there's space on the ring for this request */
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@@ -3051,23 +3052,25 @@ void p2m_mem_paging_populate(struct p2m_
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/* Allow only nominated or evicted pages to enter page-in path */
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if ( p2m_do_populate(p2mt) )
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{
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- /* Evict will fail now, tag this request for pager */
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- if ( p2mt == p2m_ram_paging_out )
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- req.flags |= MEM_EVENT_FLAG_EVICT_FAIL;
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-
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- set_p2m_entry(p2m, gfn, mfn, 0, p2m_ram_paging_in_start, a);
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+ /* Restore page state if gfn was requested before evict */
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+ if ( p2mt == p2m_ram_paging_out && mfn_valid(mfn) ) {
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+ set_p2m_entry(p2m, gfn, mfn, 0, p2m_ram_rw, a);
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+ restored = 1;
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+ } else {
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+ set_p2m_entry(p2m, gfn, mfn, 0, p2m_ram_paging_in_start, a);
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+ }
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audit_p2m(p2m, 1);
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}
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p2m_unlock(p2m);
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/* Pause domain if request came from guest and gfn has paging type */
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- if ( p2m_is_paging(p2mt) && v->domain == d )
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+ if ( !restored && p2m_is_paging(p2mt) && v->domain == d )
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{
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vcpu_pause_nosync(v);
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req.flags |= MEM_EVENT_FLAG_VCPU_PAUSED;
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}
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/* No need to inform pager if the gfn is not in the page-out path */
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- else if ( !p2m_do_populate(p2mt) )
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+ else if ( restored || !p2m_do_populate(p2mt) )
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{
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/* gfn is already on its way back and vcpu is not paused */
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mem_event_put_req_producers(&d->mem_event->paging);
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