linux-kernel - [PATCH v6 09/13] x86/kvm/nVMX: allow bare VMXON state migration

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: <20181016165011.6607-10-vkuznets@redhat.com>
Date:   Tue, 16 Oct 2018 18:50:07 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Roman Kagan <rkagan@...tuozzo.com>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "Michael Kelley (EOSG)" <Michael.H.Kelley@...rosoft.com>,
        linux-kernel@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        Liran Alon <liran.alon@...cle.com>
Subject: [PATCH v6 09/13] x86/kvm/nVMX: allow bare VMXON state migration

It is perfectly valid for a guest to do VMXON and not do VMPTRLD. This
state needs to be preserved on migration.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/kvm/vmx.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0b665c74fadc..5df47291ad4d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -14827,13 +14827,6 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
 	if (!page_address_valid(vcpu, kvm_state->vmx.vmxon_pa))
 		return -EINVAL;
 
-	if (kvm_state->size < sizeof(kvm_state) + sizeof(*vmcs12))
-		return -EINVAL;
-
-	if (kvm_state->vmx.vmcs_pa == kvm_state->vmx.vmxon_pa ||
-	    !page_address_valid(vcpu, kvm_state->vmx.vmcs_pa))
-		return -EINVAL;
-
 	if ((kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
 	    (kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
 		return -EINVAL;
@@ -14863,6 +14856,14 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
 	if (ret)
 		return ret;
 
+	/* Empty 'VMXON' state is permitted */
+	if (kvm_state->size < sizeof(kvm_state) + sizeof(*vmcs12))
+		return 0;
+
+	if (kvm_state->vmx.vmcs_pa == kvm_state->vmx.vmxon_pa ||
+	    !page_address_valid(vcpu, kvm_state->vmx.vmcs_pa))
+		return -EINVAL;
+
 	set_current_vmptr(vmx, kvm_state->vmx.vmcs_pa);
 
 	if (kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON) {
-- 
2.17.1