From: Wanpeng Li <wanpengli@tencent.com>
Date: Sun, 13 May 2018 02:24:47 -0700
Subject: KVM: X86: Fix reserved bits check for MOV to CR3
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Git-commit: a780a3ea628268b2ad0ed43d7f28d90db0ff18be
Patch-mainline: v4.18-rc1
References: bsc#1110006
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: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kvm/emulate.c | 4 +++-
arch/x86/kvm/x86.c | 2 +-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b3705ae52824..143b7ae52624 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);
+ rsvd = rsvd_bits(maxphyaddr, 63);
+ if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)
+ rsvd &= ~CR3_PCID_INVD;
}
if (new_val & rsvd)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 37dd9a9d050a..e6b4e5665d74 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -856,7 +856,7 @@ 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))