linux-kernel - [PATCH v3 5/5] KVM: nVMX: load GUEST_EFER after GUEST

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1480472050-58023-6-git-send-email-dmatlack@google.com>
Date:   Tue, 29 Nov 2016 18:14:10 -0800
From:   David Matlack <dmatlack@...gle.com>
To:     kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jmattson@...gle.com,
        rkrcmar@...hat.com, pbonzini@...hat.com,
        David Matlack <dmatlack@...gle.com>
Subject: [PATCH v3 5/5] KVM: nVMX: load GUEST_EFER after GUEST_CR0 during emulated VM-entry

vmx_set_cr0() modifies GUEST_EFER and "IA-32e mode guest" in the current
VMCS. Call vmx_set_efer() after vmx_set_cr0() so that emulated VM-entry
is more faithful to VMCS12.

This patch correctly causes VM-entry to fail when "IA-32e mode guest" is
1 and GUEST_CR0.PG is 0. Previously this configuration would succeed and
"IA-32e mode guest" would silently be disabled by KVM.

Signed-off-by: David Matlack <dmatlack@...gle.com>
---
 arch/x86/kvm/vmx.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 49270c4..776dc67 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10386,15 +10386,6 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 		nested_ept_init_mmu_context(vcpu);
 	}
 
-	if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER)
-		vcpu->arch.efer = vmcs12->guest_ia32_efer;
-	else if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE)
-		vcpu->arch.efer |= (EFER_LMA | EFER_LME);
-	else
-		vcpu->arch.efer &= ~(EFER_LMA | EFER_LME);
-	/* Note: modifies VM_ENTRY/EXIT_CONTROLS and GUEST/HOST_IA32_EFER */
-	vmx_set_efer(vcpu, vcpu->arch.efer);
-
 	/*
 	 * This sets GUEST_CR0 to vmcs12->guest_cr0, with possibly a modified
 	 * TS bit (for lazy fpu) and bits which we consider mandatory enabled.
@@ -10409,6 +10400,15 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 	vmx_set_cr4(vcpu, vmcs12->guest_cr4);
 	vmcs_writel(CR4_READ_SHADOW, nested_read_cr4(vmcs12));
 
+	if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER)
+		vcpu->arch.efer = vmcs12->guest_ia32_efer;
+	else if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE)
+		vcpu->arch.efer |= (EFER_LMA | EFER_LME);
+	else
+		vcpu->arch.efer &= ~(EFER_LMA | EFER_LME);
+	/* Note: modifies VM_ENTRY/EXIT_CONTROLS and GUEST/HOST_IA32_EFER */
+	vmx_set_efer(vcpu, vcpu->arch.efer);
+
 	/* shadow page tables on either EPT or shadow page tables */
 	kvm_set_cr3(vcpu, vmcs12->guest_cr3);
 	kvm_mmu_reset_context(vcpu);
-- 
2.8.0.rc3.226.g39d4020