From b6e30e966ade04c331eeb293d79a343402618ef3 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 27 Feb 2015 15:45:29 +0100 Subject: [PATCH] x86/xen: correct bug in p2m list initialization Commit 8e0f8ed37c60faa0a62b7d951fd4b90882a794cf ("xen: switch to linear virtual mapped sparse p2m list") introduced an error. During initialization of the p2m list a p2m identity area mapped by a complete identity pmd entry has to be split up into smaller chunks sometimes, if a non-identity pfn is introduced in this area. If this non-identity pfn is not at index 0 of a p2m page the new p2m page needed is initialized with wrong identity entries, as the identity pfns don't start with the value corresponding to index 0, but with the initial non-identity pfn. This results in weird wrong mappings. Correct the wrong initialization by starting with the correct pfn. Cc: stable@vger.kernel.org # 3.19 Reported-by: Stefan Bader Signed-off-by: Juergen Gross Tested-by: Stefan Bader Signed-off-by: David Vrabel --- arch/x86/xen/p2m.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 740ae3026a148..9f93af56a5fc7 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -563,7 +563,7 @@ static bool alloc_p2m(unsigned long pfn) if (p2m_pfn == PFN_DOWN(__pa(p2m_missing))) p2m_init(p2m); else - p2m_init_identity(p2m, pfn); + p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1)); spin_lock_irqsave(&p2m_update_lock, flags); -- 2.39.5