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Commit 9791d9d7 authored by Wanpeng Li's avatar Wanpeng Li Committed by Greg Kroah-Hartman
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KVM: X86: Fix reserved bits check for MOV to CR3 



commit a780a3ea628268b2ad0ed43d7f28d90db0ff18be upstream.

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
'd1cd3ce9 ("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: d1cd3ce9 (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: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarJunaid Shahid <junaids@google.com>
Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c7a372dd

arch/x86/kvm/emulate.c

+3 −1
Original line number Diff line number Diff line
@@ -4152,7 +4152,9 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt) 
				maxphyaddr = eax & 0xff;

			else

				maxphyaddr = 36;

			rsvd = rsvd_bits(maxphyaddr, 62);

			rsvd = rsvd_bits(maxphyaddr, 63);

			if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)

				rsvd &= ~CR3_PCID_INVD;

		}



		if (new_val & rsvd)

arch/x86/kvm/x86.c

+1 −1
Original line number Diff line number Diff line
@@ -836,7 +836,7 @@ 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))