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[1/2] KVM: X86: Fix CR3 reserve bits

Message ID 1526181725-3568-1-git-send-email-wanpengli@tencent.com (mailing list archive)
State New, archived
Headers show

Commit Message

Wanpeng Li May 13, 2018, 3:22 a.m. UTC 
From: Wanpeng Li <wanpengli@tencent.com>

MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4. 
It should be checked when PCIDE bit is not set, however commit 
'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on 
its physical address width")' removes the bit 63 checking 
unconditionally. This patch fixes it by checking bit 63 of CR3 
when PCIDE bit is not set in CR4.

Fixes: d1cd3ce900441 (KVM: MMU: check guest CR3 reserved bits based on its physical address width)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Junaid Shahid <junaids@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
 arch/x86/kvm/emulate.c | 4 +++-
 arch/x86/kvm/x86.c     | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b3705ae..b21f427 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4189,7 +4189,9 @@  static int check_cr_write(struct x86_emulate_ctxt *ctxt)
 				maxphyaddr = eax & 0xff;
 			else
 				maxphyaddr = 36;
-			rsvd = rsvd_bits(maxphyaddr, 62);
+			if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)
+				new_val &= ~CR3_PCID_INVD;
+			rsvd = rsvd_bits(maxphyaddr, 63);
 		}
 
 		if (new_val & rsvd)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 87e4805..9a90668 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -863,7 +863,7 @@  int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 	}
 
 	if (is_long_mode(vcpu) &&
-	    (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 62)))
+	    (cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
 		return 1;
 	else if (is_pae(vcpu) && is_paging(vcpu) &&
 		   !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))