54 lines
1.8 KiB
Diff
54 lines
1.8 KiB
Diff
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changeset: 23943:1185ae04b5aa
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user: Olaf Hering <olaf@aepfle.de>
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date: Tue Oct 11 10:46:28 2011 +0100
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files: tools/xenpaging/xenpaging.c xen/arch/x86/mm/p2m.c
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description:
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xenpaging: clear page content after evict
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If the guest happens to read from the gfn while xenpaging is in the process of
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evicting the page, the guest may read zeros instead of actual data.
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Also if eviction fails the page content will be corrupted and xenpaging wont
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attempt to restore the page.
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Remove page scrubbing from pager and do it after successful eviction.
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Signed-off-by: Olaf Hering <olaf@aepfle.de>
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Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
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Acked-by: Tim Deegan <tim@xen.org>
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Committed-by: Tim Deegan <tim@xen.org>
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---
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tools/xenpaging/xenpaging.c | 3 ---
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xen/arch/x86/mm/p2m.c | 3 +++
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2 files changed, 3 insertions(+), 3 deletions(-)
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Index: xen-4.1.2-testing/tools/xenpaging/xenpaging.c
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===================================================================
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--- xen-4.1.2-testing.orig/tools/xenpaging/xenpaging.c
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+++ xen-4.1.2-testing/tools/xenpaging/xenpaging.c
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@@ -455,9 +455,6 @@ static int xenpaging_evict_page(xenpagin
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goto out;
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}
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- /* Clear page */
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- memset(page, 0, PAGE_SIZE);
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-
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munmap(page, PAGE_SIZE);
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/* Tell Xen to evict page */
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Index: xen-4.1.2-testing/xen/arch/x86/mm/p2m.c
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===================================================================
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--- xen-4.1.2-testing.orig/xen/arch/x86/mm/p2m.c
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+++ xen-4.1.2-testing/xen/arch/x86/mm/p2m.c
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@@ -2916,6 +2916,9 @@ int p2m_mem_paging_evict(struct p2m_doma
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set_p2m_entry(p2m, gfn, _mfn(PAGING_MFN), 0, p2m_ram_paged, a);
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audit_p2m(p2m, 1);
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+ /* Clear content before returning the page to Xen */
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+ scrub_one_page(page);
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+
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/* Put the page back so it gets freed */
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put_page(page);
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