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,
Maxim Levitsky <mlevitsk@redhat.com>,
"Maciej S . Szmigiero" <maciej.szmigiero@oracle.com>
Subject: [PATCH v2 06/11] KVM: SVM: Re-inject INTn instead of retrying the insn on "failure"
Date: Sat, 23 Apr 2022 02:14:06 +0000 [thread overview]
Message-ID: <20220423021411.784383-7-seanjc@google.com> (raw)
In-Reply-To: <20220423021411.784383-1-seanjc@google.com>
Re-inject INTn software interrupts instead of retrying the instruction if
the CPU encountered an intercepted exception while vectoring the INTn,
e.g. if KVM intercepted a #PF when utilizing shadow paging. Retrying the
instruction is architecturally wrong e.g. will result in a spurious #DB
if there's a code breakpoint on the INT3/O, and lack of re-injection also
breaks nested virtualization, e.g. if L1 injects a software interrupt and
vectoring the injected interrupt encounters an exception that is
intercepted by L0 but not L1.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/nested.c | 7 +++----
arch/x86/kvm/svm/svm.c | 24 +++++++++++++++++++-----
2 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 0163238aa198..a83e367ade54 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -617,10 +617,9 @@ static inline bool is_evtinj_soft(u32 evtinj)
if (!(evtinj & SVM_EVTINJ_VALID))
return false;
- /*
- * Intentionally return false for SOFT events, SVM doesn't yet support
- * re-injecting soft interrupts.
- */
+ if (type == SVM_EVTINJ_TYPE_SOFT)
+ return true;
+
return type == SVM_EVTINJ_TYPE_EXEPT && kvm_exception_is_soft(vector);
}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 8321f9ce5e35..b8fb07eeeca5 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3430,14 +3430,23 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu)
static void svm_inject_irq(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
+ u32 type;
- WARN_ON(!vcpu->arch.interrupt.soft && !gif_set(svm));
+ if (vcpu->arch.interrupt.soft) {
+ if (svm_update_soft_interrupt_rip(vcpu))
+ return;
+
+ type = SVM_EVTINJ_TYPE_SOFT;
+ } else {
+ WARN_ON(!gif_set(svm));
+ type = SVM_EVTINJ_TYPE_INTR;
+ }
trace_kvm_inj_virq(vcpu->arch.interrupt.nr);
++vcpu->stat.irq_injections;
svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr |
- SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR;
+ SVM_EVTINJ_VALID | type;
}
void svm_complete_interrupt_delivery(struct kvm_vcpu *vcpu, int delivery_mode,
@@ -3717,6 +3726,8 @@ static inline void sync_lapic_to_cr8(struct kvm_vcpu *vcpu)
static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector,
int type)
{
+ bool is_exception = (type == SVM_EXITINTINFO_TYPE_EXEPT);
+ bool is_soft = (type == SVM_EXITINTINFO_TYPE_SOFT);
struct vcpu_svm *svm = to_svm(vcpu);
/*
@@ -3728,8 +3739,7 @@ static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector,
* the same event, i.e. if the event is a soft exception/interrupt,
* otherwise next_rip is unused on VMRUN.
*/
- if (nrips && type == SVM_EXITINTINFO_TYPE_EXEPT &&
- kvm_exception_is_soft(vector) &&
+ if (nrips && (is_soft || (is_exception && kvm_exception_is_soft(vector))) &&
kvm_is_linear_rip(vcpu, svm->soft_int_old_rip + svm->soft_int_csbase))
svm->vmcb->control.next_rip = svm->soft_int_next_rip;
/*
@@ -3740,7 +3750,7 @@ static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector,
* hit a #NP in the guest, and the #NP encountered a #PF, the #NP will
* be the reported vectored event, but RIP still needs to be unwound.
*/
- else if (!nrips && type == SVM_EXITINTINFO_TYPE_EXEPT &&
+ else if (!nrips && (is_soft || is_exception) &&
kvm_is_linear_rip(vcpu, svm->soft_int_next_rip + svm->soft_int_csbase))
kvm_rip_write(vcpu, svm->soft_int_old_rip);
}
@@ -3802,9 +3812,13 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu)
case SVM_EXITINTINFO_TYPE_INTR:
kvm_queue_interrupt(vcpu, vector, false);
break;
+ case SVM_EXITINTINFO_TYPE_SOFT:
+ kvm_queue_interrupt(vcpu, vector, true);
+ break;
default:
break;
}
+
}
static void svm_cancel_injection(struct kvm_vcpu *vcpu)
--
2.36.0.rc2.479.g8af0fa9b8e-goog
next prev parent reply other threads:[~2022-04-23 2:14 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-23 2:14 [PATCH v2 00/11] KVM: SVM: Fix soft int/ex re-injection Sean Christopherson
2022-04-23 2:14 ` [PATCH v2 01/11] KVM: nSVM: Sync next_rip field from vmcb12 to vmcb02 Sean Christopherson
2022-04-28 9:33 ` Maxim Levitsky
2022-04-23 2:14 ` [PATCH v2 02/11] KVM: SVM: Don't BUG if userspace injects a soft interrupt with GIF=0 Sean Christopherson
2022-04-28 7:35 ` Maxim Levitsky
2022-04-28 13:27 ` Maciej S. Szmigiero
2022-04-28 14:34 ` Maxim Levitsky
2022-04-28 15:04 ` Sean Christopherson
2022-04-28 16:33 ` Maciej S. Szmigiero
2022-04-23 2:14 ` [PATCH v2 03/11] KVM: SVM: Unwind "speculative" RIP advancement if INTn injection "fails" Sean Christopherson
2022-04-23 2:14 ` [PATCH v2 04/11] KVM: SVM: Stuff next_rip on emulated INT3 injection if NRIPS is supported Sean Christopherson
2022-04-23 2:14 ` [PATCH v2 05/11] KVM: SVM: Re-inject INT3/INTO instead of retrying the instruction Sean Christopherson
2022-04-25 22:59 ` Maciej S. Szmigiero
2022-04-28 9:37 ` Maxim Levitsky
2022-04-28 13:36 ` Maciej S. Szmigiero
2022-04-28 14:25 ` Sean Christopherson
2022-04-23 2:14 ` Sean Christopherson [this message]
2022-04-23 2:14 ` [PATCH v2 07/11] KVM: x86: Trace re-injected exceptions Sean Christopherson
2022-04-28 9:48 ` Maxim Levitsky
2022-04-23 2:14 ` [PATCH v2 08/11] KVM: x86: Print error code in exception injection tracepoint iff valid Sean Christopherson
2022-04-28 9:49 ` Maxim Levitsky
2022-04-23 2:14 ` [PATCH v2 09/11] KVM: x86: Differentiate Soft vs. Hard IRQs vs. reinjected in tracepoint Sean Christopherson
2022-04-25 22:59 ` Maciej S. Szmigiero
2022-04-23 2:14 ` [PATCH v2 10/11] KVM: selftests: nSVM: Add svm_nested_soft_inject_test Sean Christopherson
2022-04-25 23:00 ` Maciej S. Szmigiero
2022-04-23 2:14 ` [PATCH v2 11/11] KVM: SVM: Drop support for CPUs without NRIPS (NextRIP Save) support Sean Christopherson
2022-04-24 9:34 ` Maxim Levitsky
2022-04-25 23:00 ` Maciej S. Szmigiero
2022-04-25 23:01 ` [PATCH v2 00/11] KVM: SVM: Fix soft int/ex re-injection Maciej S. Szmigiero
2022-04-27 18:21 ` Maciej S. Szmigiero
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