linux-kernel - [PATCH v5 1/9] KVM: MMU: fix forgot reserved bits check in speculative path

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Date:	Tue, 06 Jul 2010 18:44:40 +0800
From:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
To:	Avi Kivity <avi@...hat.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	KVM list <kvm@...r.kernel.org>
Subject: [PATCH v5 1/9] KVM: MMU: fix forgot reserved bits check in speculative
 path

In the speculative path, we should check guest pte's reserved bits just as
the real processor does

Reported-by: Marcelo Tosatti <mtosatti@...hat.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
---
 arch/x86/kvm/mmu.c         |    3 +++
 arch/x86/kvm/paging_tmpl.h |    3 ++-
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 104756b..3dcd55d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2781,6 +2781,9 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 		break;
 	}
 
+	if (is_rsvd_bits_set(vcpu, gentry, PT_PAGE_TABLE_LEVEL))
+		gentry = 0;
+
 	mmu_guess_page_from_pte_write(vcpu, gpa, gentry);
 	spin_lock(&vcpu->kvm->mmu_lock);
 	if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index dfb2720..19f0077 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -628,7 +628,8 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 		pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);
 
 		if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
-					  sizeof(pt_element_t)))
+					  sizeof(pt_element_t)) ||
+		      is_rsvd_bits_set(vcpu, gpte, PT_PAGE_TABLE_LEVEL))
 			return -EINVAL;
 
 		gfn = gpte_to_gfn(gpte);
-- 
1.6.1.2

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