From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Xiaoyao Li <xiaoyao.li@intel.com>,
Reiji Watanabe <reijiw@google.com>
Subject: [PATCH 05/15] KVM: VMX: Disable preemption when probing user return MSRs
Date: Tue, 4 May 2021 10:17:24 -0700 [thread overview]
Message-ID: <20210504171734.1434054-6-seanjc@google.com> (raw)
In-Reply-To: <20210504171734.1434054-1-seanjc@google.com>
Disable preemption when probing a user return MSR via RDSMR/WRMSR. If
the MSR holds a different value per logical CPU, the WRMSR could corrupt
the host's value if KVM is preempted between the RDMSR and WRMSR, and
then rescheduled on a different CPU.
Opportunistically land the helper in common x86, SVM will use the helper
in a future commit.
Fixes: 4be534102624 ("KVM: VMX: Initialize vmx->guest_msrs[] right after allocation")
Cc: stable@vger.kernel.org
Cc: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/vmx/vmx.c | 5 +----
arch/x86/kvm/x86.c | 16 ++++++++++++++++
3 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3e5fc80a35c8..a02c9bf3f7f1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1778,6 +1778,7 @@ int kvm_pv_send_ipi(struct kvm *kvm, unsigned long ipi_bitmap_low,
unsigned long icr, int op_64_bit);
void kvm_define_user_return_msr(unsigned index, u32 msr);
+int kvm_probe_user_return_msr(u32 msr);
int kvm_set_user_return_msr(unsigned index, u64 val, u64 mask);
u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 99591e523b47..990ee339a05f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6914,12 +6914,9 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
for (i = 0; i < ARRAY_SIZE(vmx_uret_msrs_list); ++i) {
u32 index = vmx_uret_msrs_list[i];
- u32 data_low, data_high;
int j = vmx->nr_uret_msrs;
- if (rdmsr_safe(index, &data_low, &data_high) < 0)
- continue;
- if (wrmsr_safe(index, data_low, data_high) < 0)
+ if (kvm_probe_user_return_msr(index))
continue;
vmx->guest_uret_msrs[j].slot = i;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3bf52ba5f2bb..e304447be42d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -339,6 +339,22 @@ static void kvm_on_user_return(struct user_return_notifier *urn)
}
}
+int kvm_probe_user_return_msr(u32 msr)
+{
+ u64 val;
+ int ret;
+
+ preempt_disable();
+ ret = rdmsrl_safe(msr, &val);
+ if (ret)
+ goto out;
+ ret = wrmsrl_safe(msr, val);
+out:
+ preempt_enable();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_probe_user_return_msr);
+
void kvm_define_user_return_msr(unsigned slot, u32 msr)
{
BUG_ON(slot >= KVM_MAX_NR_USER_RETURN_MSRS);
--
2.31.1.527.g47e6f16901-goog
next prev parent reply other threads:[~2021-05-04 17:18 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-04 17:17 [PATCH 00/15] KVM: x86: RDPID/RDTSCP fixes and uret MSR cleanups Sean Christopherson
2021-05-04 17:17 ` [PATCH 01/15] KVM: VMX: Do not adverise RDPID if ENABLE_RDTSCP control is unsupported Sean Christopherson
2021-05-04 17:37 ` Jim Mattson
2021-05-04 17:53 ` Jim Mattson
2021-05-04 18:14 ` Sean Christopherson
2021-05-05 3:04 ` Reiji Watanabe
2021-05-10 8:03 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 02/15] KVM: x86: Emulate RDPID only if RDTSCP is supported Sean Christopherson
2021-05-04 17:50 ` Jim Mattson
2021-05-05 3:51 ` Reiji Watanabe
2021-05-05 8:01 ` Paolo Bonzini
2021-05-10 8:08 ` Maxim Levitsky
2021-05-10 17:20 ` Sean Christopherson
2021-05-11 12:32 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 03/15] KVM: SVM: Inject #UD on RDTSCP when it should be disabled in the guest Sean Christopherson
2021-05-04 21:45 ` Jim Mattson
2021-05-04 21:53 ` Sean Christopherson
2021-05-04 21:56 ` Jim Mattson
2021-05-04 22:10 ` Sean Christopherson
2021-05-04 22:24 ` Jim Mattson
2021-05-04 21:57 ` Paolo Bonzini
2021-05-04 21:58 ` Jim Mattson
2021-05-10 8:08 ` Maxim Levitsky
2021-05-10 16:56 ` Sean Christopherson
2021-05-11 12:34 ` Maxim Levitsky
2021-05-18 10:59 ` Paolo Bonzini
2021-05-18 19:24 ` Sean Christopherson
2021-05-05 4:26 ` Reiji Watanabe
2021-05-10 8:08 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 04/15] KVM: x86: Move RDPID emulation intercept to its own enum Sean Christopherson
2021-05-04 23:24 ` Jim Mattson
2021-05-10 8:14 ` Maxim Levitsky
2021-05-04 17:17 ` Sean Christopherson [this message]
2021-05-04 23:36 ` [PATCH 05/15] KVM: VMX: Disable preemption when probing user return MSRs Jim Mattson
2021-05-10 8:18 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 06/15] KVM: SVM: Probe and load MSR_TSC_AUX regardless of RDTSCP support in host Sean Christopherson
2021-05-10 8:20 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 07/15] KVM: x86: Add support for RDPID without RDTSCP Sean Christopherson
2021-05-10 8:20 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 08/15] KVM: VMX: Configure list of user return MSRs at module init Sean Christopherson
2021-05-10 8:23 ` Maxim Levitsky
2021-05-10 15:13 ` Sean Christopherson
2021-05-11 12:34 ` Maxim Levitsky
2021-05-11 20:10 ` Sean Christopherson
2021-05-04 17:17 ` [PATCH 09/15] KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting list Sean Christopherson
2021-05-08 3:31 ` Reiji Watanabe
2021-05-10 16:43 ` Sean Christopherson
2021-05-10 17:55 ` Reiji Watanabe
2021-05-10 8:25 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 10/15] KVM: VMX: Use common x86's uret MSR list as the one true list Sean Christopherson
2021-05-10 8:25 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 11/15] KVM: VMX: Disable loading of TSX_CTRL MSR the more conventional way Sean Christopherson
2021-05-05 8:49 ` Paolo Bonzini
2021-05-05 15:36 ` Sean Christopherson
2021-05-05 15:50 ` Paolo Bonzini
2021-05-10 8:26 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 12/15] KVM: x86: Export the number of uret MSRs to vendor modules Sean Christopherson
2021-05-10 8:27 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 13/15] KVM: x86: Move uret MSR slot management to common x86 Sean Christopherson
2021-05-10 8:28 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 14/15] KVM: x86: Tie Intel and AMD behavior for MSR_TSC_AUX to guest CPU model Sean Christopherson
2021-05-10 8:29 ` Maxim Levitsky
2021-05-10 16:50 ` Sean Christopherson
2021-05-10 17:11 ` Jim Mattson
2021-05-11 12:34 ` Maxim Levitsky
2021-05-04 17:17 ` [PATCH 15/15] KVM: x86: Hide RDTSCP and RDPID if MSR_TSC_AUX probing failed Sean Christopherson
2021-05-10 8:29 ` Maxim Levitsky
2021-05-05 8:51 ` [PATCH 00/15] KVM: x86: RDPID/RDTSCP fixes and uret MSR cleanups Paolo Bonzini
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