From b8f05c8803fce899d79ca66f8d7f348cf15fb40e 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 054954eb051f35e74b75a566a96fe756015352c8 ("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 740ae3026a14..9f93af56a5fc 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); -- 2.20.1