From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: jmattson@google.com, aliguori@amazon.com,
thomas.lendacky@amd.com, dwmw@amazon.co.uk, bp@alien8.de,
Tim Chen <tim.c.chen@linux.intel.com>
Subject: [PATCH 4/7] kvm: vmx: Set IBPB when running a different VCPU
Date: Mon, 8 Jan 2018 19:08:42 +0100 [thread overview]
Message-ID: <1515434925-10250-5-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1515434925-10250-1-git-send-email-pbonzini@redhat.com>
From: Tim Chen <tim.c.chen@linux.intel.com>
Ensure an IBPB (Indirect branch prediction barrier) before every VCPU
switch.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d00bcad7336e..bf127c570675 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2375,6 +2375,8 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (per_cpu(current_vmcs, cpu) != vmx->loaded_vmcs->vmcs) {
per_cpu(current_vmcs, cpu) = vmx->loaded_vmcs->vmcs;
vmcs_load(vmx->loaded_vmcs->vmcs);
+ if (have_spec_ctrl)
+ wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
}
if (!already_loaded) {
@@ -4029,6 +4031,13 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
free_vmcs(loaded_vmcs->vmcs);
loaded_vmcs->vmcs = NULL;
WARN_ON(loaded_vmcs->shadow_vmcs != NULL);
+
+ /*
+ * The VMCS could be recycled, causing a false negative in
+ * vmx_vcpu_load; block speculative execution.
+ */
+ if (have_spec_ctrl)
+ wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
}
static void vmx_nested_free_vmcs02(struct vcpu_vmx *vmx)
--
1.8.3.1
next prev parent reply other threads:[~2018-01-08 18:09 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-08 18:08 [PATCH 0/7] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Paolo Bonzini
2018-01-08 18:08 ` [PATCH 1/7] KVM: x86: add SPEC_CTRL and IBPB_SUPPORT accessors Paolo Bonzini
2018-01-08 18:33 ` Konrad Rzeszutek Wilk
2018-01-08 19:09 ` Liran Alon
2018-01-09 10:32 ` Paolo Bonzini
2018-01-09 11:14 ` David Hildenbrand
2018-01-09 11:18 ` Paolo Bonzini
2018-01-08 18:08 ` [PATCH 2/7] x86/msr: add definitions for indirect branch predictor MSRs Paolo Bonzini
2018-01-08 18:35 ` Konrad Rzeszutek Wilk
2018-01-08 18:52 ` Jim Mattson
2018-01-08 19:10 ` Liran Alon
2018-01-08 18:08 ` [PATCH 3/7] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest Paolo Bonzini
2018-01-08 18:43 ` Konrad Rzeszutek Wilk
2018-01-08 19:18 ` Jim Mattson
2018-01-08 20:23 ` Liran Alon
2018-01-08 22:32 ` Paolo Bonzini
2018-01-08 23:19 ` Jim Mattson
2018-01-09 10:11 ` Paolo Bonzini
2018-01-08 19:22 ` Liran Alon
2018-01-08 19:41 ` David Woodhouse
2018-01-08 22:33 ` Paolo Bonzini
2018-01-08 22:09 ` Ashok Raj
2018-01-08 22:25 ` Paolo Bonzini
2018-01-11 2:47 ` Tim Chen
2018-01-11 10:41 ` Paolo Bonzini
2018-01-08 18:08 ` Paolo Bonzini [this message]
2018-01-08 19:23 ` [PATCH 4/7] kvm: vmx: Set IBPB when running a different VCPU Liran Alon
2018-01-08 19:36 ` Jim Mattson
2018-01-09 8:33 ` Paolo Bonzini
2018-01-09 11:01 ` David Hildenbrand
2018-01-08 18:08 ` [PATCH 5/7] kvm: svm: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to guest Paolo Bonzini
2018-01-08 19:41 ` Liran Alon
2018-01-08 18:08 ` [PATCH 6/7] x86/svm: Set IBPB when running a different VCPU Paolo Bonzini
2018-01-08 20:00 ` Liran Alon
2018-01-09 11:07 ` Paolo Bonzini
2018-01-08 18:08 ` [PATCH 7/7] KVM: x86: add SPEC_CTRL and IBPB_SUPPORT to MSR and CPUID lists Paolo Bonzini
2018-01-08 20:07 ` Liran Alon
2018-01-08 20:15 ` Jim Mattson
2018-01-09 10:15 ` [PATCH 0/7] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Thomas Gleixner
2018-01-09 11:12 ` Paolo Bonzini
2018-01-09 12:03 ` Thomas Gleixner
2018-01-09 14:06 ` Paolo Bonzini
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