linux-kernel - [PATCH v3 1/10] KVM MMU: fix for calculating gpa in invlpg code

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Date:	Wed, 28 Apr 2010 11:54:44 +0800
From:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To:	Avi Kivity <avi@...hat.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	KVM list <kvm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v3 1/10] KVM MMU: fix for calculating gpa in invlpg code

If the guest is 32-bit, we should use 'quadrant' to adjust gpa
offset

Changelog v3:
- use smart way to fix this bug address Avi's suggestion

Changelog v2:
- when level is PT_DIRECTORY_LEVEL, the 'offset' should be
  'role.quadrant << 8', thanks Avi for point it out

Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
---
 arch/x86/kvm/paging_tmpl.h |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index d0cc07e..3464fdb 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -478,8 +478,13 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
 		    ((level == PT_DIRECTORY_LEVEL && is_large_pte(*sptep))) ||
 		    ((level == PT_PDPE_LEVEL && is_large_pte(*sptep)))) {
 			struct kvm_mmu_page *sp = page_header(__pa(sptep));
+			int offset, shift;
 
-			pte_gpa = (sp->gfn << PAGE_SHIFT);
+			shift = PAGE_SHIFT -
+				  (PT_LEVEL_BITS - PT64_LEVEL_BITS) * level;
+			offset = sp->role.quadrant << shift;
+
+			pte_gpa = (sp->gfn << PAGE_SHIFT) + offset;
 			pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
 
 			if (is_shadow_present_pte(*sptep)) {
-- 
1.6.1.2



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