From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: jmattson@google.com,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: [PATCH 5/5] KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it
Date: Mon, 18 Nov 2019 19:17:47 +0100 [thread overview]
Message-ID: <1574101067-5638-6-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1574101067-5638-1-git-send-email-pbonzini@redhat.com>
If X86_FEATURE_RTM is disabled, the guest should not be able to access
MSR_IA32_TSX_CTRL. We can therefore use it in KVM to force all
transactions from the guest to abort.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx/vmx.c | 44 ++++++++++++++++++++++++++++++--------------
1 file changed, 30 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ed25fe7d5234..8cba65eec0d3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -639,6 +639,23 @@ struct shared_msr_entry *find_msr_entry(struct vcpu_vmx *vmx, u32 msr)
return NULL;
}
+static int vmx_set_guest_msr(struct vcpu_vmx *vmx, struct shared_msr_entry *msr, u64 data)
+{
+ int ret = 0;
+
+ u64 old_msr_data = msr->data;
+ msr->data = data;
+ if (msr - vmx->guest_msrs < vmx->save_nmsrs) {
+ preempt_disable();
+ ret = kvm_set_shared_msr(msr->index, msr->data,
+ msr->mask);
+ preempt_enable();
+ if (ret)
+ msr->data = old_msr_data;
+ }
+ return ret;
+}
+
void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs)
{
vmcs_clear(loaded_vmcs->vmcs);
@@ -2174,20 +2191,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
default:
find_shared_msr:
msr = find_msr_entry(vmx, msr_index);
- if (msr) {
- u64 old_msr_data = msr->data;
- msr->data = data;
- if (msr - vmx->guest_msrs < vmx->save_nmsrs) {
- preempt_disable();
- ret = kvm_set_shared_msr(msr->index, msr->data,
- msr->mask);
- preempt_enable();
- if (ret)
- msr->data = old_msr_data;
- }
- break;
- }
- ret = kvm_set_msr_common(vcpu, msr_info);
+ if (msr)
+ ret = vmx_set_guest_msr(vmx, msr, data);
+ else
+ ret = kvm_set_msr_common(vcpu, msr_info);
}
return ret;
@@ -7138,6 +7145,15 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
if (boot_cpu_has(X86_FEATURE_INTEL_PT) &&
guest_cpuid_has(vcpu, X86_FEATURE_INTEL_PT))
update_intel_pt_cfg(vcpu);
+
+ if (boot_cpu_has(X86_FEATURE_RTM)) {
+ struct shared_msr_entry *msr;
+ msr = find_msr_entry(vmx, MSR_IA32_TSX_CTRL);
+ if (msr) {
+ bool enabled = guest_cpuid_has(vcpu, X86_FEATURE_RTM);
+ vmx_set_guest_msr(vmx, msr, enabled ? 0 : TSX_CTRL_RTM_DISABLE);
+ }
+ }
}
static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
--
1.8.3.1
next prev parent reply other threads:[~2019-11-18 18:18 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-18 18:17 [PATCH 0/5] KVM: vmx: implement MSR_IA32_TSX_CTRL for guests Paolo Bonzini
2019-11-18 18:17 ` [PATCH 1/5] KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES Paolo Bonzini
2019-11-18 19:39 ` Jim Mattson
2019-11-18 20:48 ` Jim Mattson
2019-11-22 20:15 ` Sean Christopherson
2019-11-18 18:17 ` [PATCH 2/5] KVM: x86: do not modify masked bits of shared MSRs Paolo Bonzini
2019-11-19 19:00 ` Jim Mattson
2019-11-18 18:17 ` [PATCH 3/5] KVM: x86: implement MSR_IA32_TSX_CTRL effect on CPUID Paolo Bonzini
2019-11-19 20:02 ` Jim Mattson
2019-11-18 18:17 ` [PATCH 4/5] KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality Paolo Bonzini
2019-11-19 21:06 ` Jim Mattson
2019-11-20 12:21 ` Paolo Bonzini
2019-12-04 23:49 ` Jim Mattson
2019-12-05 10:16 ` Paolo Bonzini
2019-11-18 18:17 ` Paolo Bonzini [this message]
2019-11-21 2:22 ` [PATCH 5/5] KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it Eduardo Habkost
2019-11-21 9:05 ` Paolo Bonzini
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