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56 lines
1.8 KiB
56 lines
1.8 KiB
Date: Fri, 27 Jun 2014 10:51:42 +0100
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From: David Vrabel <david.vrabel@citrix.com>
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Subject: xen/balloon: set ballooned out pages as invalid in p2m
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Since cd9151e26d31048b2b5e00fd02e110e07d2200c9 (xen/balloon: set a
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mapping for ballooned out pages), a ballooned out page had its entry
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in the p2m set to the MFN of one of the scratch page. This means that
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the p2m will contain many entries pointing to the same MFN.
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During a domain save, this many-to-one entries are not considered and
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the scratch page is saved multiple times. On restore the ballooned
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pages are populated with new frames and the domain may use up its
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allocation before all pages can be restores.
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Set ballooned out pages as INVALID_P2M_ENTRY in the p2m (as they
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werebefore), preventing them from being saved and re-populated on
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restore.
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Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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---
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drivers/xen/balloon.c | 12 +++++-------
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1 file changed, 5 insertions(+), 7 deletions(-)
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diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
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index b7a506f..5c660c7 100644
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--- a/drivers/xen/balloon.c
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+++ b/drivers/xen/balloon.c
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@@ -426,20 +426,18 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
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* p2m are consistent.
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*/
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if (!xen_feature(XENFEAT_auto_translated_physmap)) {
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- unsigned long p;
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- struct page *scratch_page = get_balloon_scratch_page();
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-
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if (!PageHighMem(page)) {
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+ struct page *scratch_page = get_balloon_scratch_page();
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+
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ret = HYPERVISOR_update_va_mapping(
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(unsigned long)__va(pfn << PAGE_SHIFT),
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pfn_pte(page_to_pfn(scratch_page),
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PAGE_KERNEL_RO), 0);
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BUG_ON(ret);
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- }
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- p = page_to_pfn(scratch_page);
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- __set_phys_to_machine(pfn, pfn_to_mfn(p));
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- put_balloon_scratch_page();
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+ put_balloon_scratch_page();
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+ }
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+ __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
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}
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#endif
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--
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1.7.10.4
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