From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: rkrcmar@redhat.com, liran.alon@oracle.com, jmattson@google.com,
aliguori@amazon.com, thomas.lendacky@amd.com, dwmw@amazon.co.uk,
bp@alien8.de, x86@kernel.org,
Tim Chen <tim.c.chen@linux.intel.com>
Subject: [PATCH 4/8] kvm: vmx: Set IBPB when running a different VCPU
Date: Tue, 9 Jan 2018 13:03:06 +0100 [thread overview]
Message-ID: <20180109120311.27565-5-pbonzini@redhat.com> (raw)
In-Reply-To: <20180109120311.27565-1-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>
Reviewed-by: Liran Alon <liran.alon@oracle.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 ef603692aa98..49b4a2d61603 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, PRED_CMD_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, PRED_CMD_IBPB);
}
static void vmx_nested_free_vmcs02(struct vcpu_vmx *vmx)
--
1.8.3.1
next prev parent reply other threads:[~2018-01-09 12:05 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 12:03 [PATCH v2 0/8] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Paolo Bonzini
2018-01-09 12:03 ` [PATCH 1/8] KVM: x86: add SPEC_CTRL and IBPB_SUPPORT accessors Paolo Bonzini
2018-01-15 9:42 ` David Hildenbrand
2018-01-09 12:03 ` [PATCH 2/8] x86/msr: add definitions for indirect branch predictor MSRs Paolo Bonzini
2018-01-09 12:03 ` [PATCH 3/8] kvm: vmx: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to the guest Paolo Bonzini
2018-01-13 10:16 ` Longpeng (Mike)
2018-01-15 9:23 ` Paolo Bonzini
2018-01-15 9:34 ` Thomas Gleixner
2018-01-09 12:03 ` Paolo Bonzini [this message]
2018-01-12 1:49 ` [PATCH 4/8] kvm: vmx: Set IBPB when running a different VCPU Wanpeng Li
2018-01-12 17:03 ` Jim Mattson
2018-01-13 9:29 ` Woodhouse, David
2018-01-15 9:21 ` Paolo Bonzini
2018-01-09 12:03 ` [PATCH 5/8] KVM: SVM: fix comment Paolo Bonzini
2018-01-15 9:53 ` David Hildenbrand
2018-01-09 12:03 ` [PATCH 6/8] kvm: svm: pass MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD down to guest Paolo Bonzini
2018-01-09 14:22 ` Konrad Rzeszutek Wilk
2018-01-09 16:05 ` Paolo Bonzini
2018-01-09 16:08 ` Paolo Bonzini
2018-01-11 10:45 ` Wanpeng Li
2018-01-10 20:13 ` Tom Lendacky
2018-01-11 10:33 ` Paolo Bonzini
2018-01-09 12:03 ` [PATCH 7/8] x86/svm: Set IBPB when running a different VCPU Paolo Bonzini
2018-01-09 14:23 ` Konrad Rzeszutek Wilk
2018-01-09 12:03 ` [PATCH 8/8] KVM: x86: add SPEC_CTRL and IBPB_SUPPORT to MSR and CPUID lists Paolo Bonzini
2018-01-13 1:25 ` Eric Wheeler
2018-01-13 8:00 ` Paolo Bonzini
2018-01-16 0:40 ` Eric Wheeler
2018-01-16 7:39 ` R: " Paolo Bonzini
2018-01-09 12:03 ` [PATCH 9/8] KVM: x86: limit MSR_IA32_SPEC_CTRL access based on CPUID availability Paolo Bonzini
2018-01-16 0:55 ` Eric Wheeler
2018-01-16 12:59 ` Paolo Bonzini
2018-01-30 13:21 ` [9/8] " Mihai Carabas
2018-01-30 16:33 ` Jim Mattson
2018-01-30 16:43 ` Mihai Carabas
2018-01-30 16:57 ` Jim Mattson
2018-01-30 17:14 ` David Woodhouse
2018-01-30 17:38 ` Jim Mattson
2018-01-30 17:45 ` Thomas Gleixner
2018-01-30 23:11 ` Paolo Bonzini
2018-01-30 23:47 ` David Woodhouse
2018-01-31 1:06 ` Paolo Bonzini
2018-02-05 11:10 ` Ingo Molnar
2018-02-05 11:15 ` David Woodhouse
2018-02-05 12:10 ` Ingo Molnar
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