linux-kernel - [PATCH] KVM: MMU: fix huge page adapted on non-PAE host

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Date:	Mon, 28 May 2012 14:10:43 +0800
From:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
To:	Avi Kivity <avi@...hat.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH] KVM: MMU: fix huge page adapted on non-PAE host

The huge page size is 4M on non-PAE host, but 2M page size is used in
transparent_hugepage_adjust(), so the page we get after adjust the
mapping level is not the head page, the BUG_ON() will be triggered

Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
---
 arch/x86/kvm/mmu.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72102e0..be3cea4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2595,8 +2595,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
 			*gfnp = gfn;
 			kvm_release_pfn_clean(pfn);
 			pfn &= ~mask;
-			if (!get_page_unless_zero(pfn_to_page(pfn)))
-				BUG();
+			kvm_get_pfn(pfn);
 			*pfnp = pfn;
 		}
 	}
-- 
1.7.7.6

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