From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Date: Mon, 28 May 2012 06:10:43 +0000 (+0800)
Subject: KVM: MMU: fix huge page adapted on non-PAE host
X-Git-Tag: Ubuntu-snapdragon-4.4.0-1029.32~13143^2~1
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=c35866678391861942b3836c219a8898a259255a;p=mirror_ubuntu-zesty-kernel.git

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@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 72102e0ab7cb..be3cea4407ff 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;
 		}
 	}