From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Joerg Roedel <joro@8bytes.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
kvm@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul
Date: Thu, 9 Dec 2021 15:45:24 +0000 [thread overview]
Message-ID: <YbIklNHIFnREGFAp@google.com> (raw)
In-Reply-To: <346f5a5e93077ba20188a9b0e67bb3a44e2cad48.camel@redhat.com>
On Thu, Dec 09, 2021, Maxim Levitsky wrote:
> On Thu, 2021-12-09 at 15:29 +0100, Paolo Bonzini wrote:
> > On 12/9/21 01:02, Sean Christopherson wrote:
> > > RDX, a.k.a. ir_data is NULL. This check in svm_ir_list_add()
> > >
> > > if (pi->ir_data && (pi->prev_ga_tag != 0)) {
> > >
> > > implies pi->ir_data can be NULL, but neither avic_update_iommu_vcpu_affinity()
> > > nor amd_iommu_update_ga() check ir->data for NULL.
> > >
> > > amd_ir_set_vcpu_affinity() returns "success" without clearing pi.is_guest_mode
> > >
> > > /* Note:
> > > * This device has never been set up for guest mode.
> > > * we should not modify the IRTE
> > > */
> > > if (!dev_data || !dev_data->use_vapic)
> > > return 0;
> > >
> > > so it's plausible svm_ir_list_add() could add to the list with a NULL pi->ir_data.
> > >
> > > But none of the relevant code has seen any meaningful changes since 5.15, so odds
> > > are good I broke something :-/
>
> Doesn't reproduce here yet even with my iommu changes :-(
> Oh well.
Hmm, which suggests it could be an existing corner case.
Based on the above, this seems prudent and correct:
@@ -747,7 +754,7 @@ static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
* so we need to check here if it's already been * added
* to the ir_list.
*/
- if (pi->ir_data && (pi->prev_ga_tag != 0)) {
+ if (pi->prev_ga_tag != 0) {
struct kvm *kvm = svm->vcpu.kvm;
u32 vcpu_id = AVIC_GATAG_TO_VCPUID(pi->prev_ga_tag);
struct kvm_vcpu *prev_vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id);
@@ -877,7 +884,7 @@ int svm_update_pi_irte(struct kvm *kvm, unsigned int host_irq,
* we can reference to them directly when we update vcpu
* scheduling information in IOMMU irte.
*/
- if (!ret && pi.is_guest_mode)
+ if (!ret && pi.is_guest_mode && pi.ir_data)
svm_ir_list_add(svm, &pi);
} else {
/* Use legacy mode in IRTE */
@@ -898,7 +905,7 @@ int svm_update_pi_irte(struct kvm *kvm, unsigned int host_irq,
* was cached. If so, we need to clean up the per-vcpu
* ir_list.
*/
- if (!ret && pi.prev_ga_tag) {
+ if (!ret && pi.prev_ga_tag && !WARN_ON(!pi.ir_data)) {
int id = AVIC_GATAG_TO_VCPUID(pi.prev_ga_tag);
struct kvm_vcpu *vcpu;
next prev parent reply other threads:[~2021-12-09 15:45 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 1:52 [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 01/26] KVM: fix avic_set_running for preemptable kernels Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 02/26] KVM: nVMX: Ensure vCPU honors event request if posting nested IRQ fails Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 03/26] KVM: VMX: Clean up PI pre/post-block WARNs Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 04/26] KVM: VMX: Handle PI wakeup shenanigans during vcpu_put/load Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 05/26] KVM: Drop unused kvm_vcpu.pre_pcpu field Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 06/26] KVM: Move x86 VMX's posted interrupt list_head to vcpu_vmx Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 07/26] KVM: VMX: Move preemption timer <=> hrtimer dance to common x86 Sean Christopherson
2023-03-29 12:34 ` Tudor Ambarus
2023-03-29 13:47 ` Paolo Bonzini
2023-03-29 15:22 ` Tudor Ambarus
2023-03-30 7:12 ` Tudor Ambarus
2021-12-08 1:52 ` [PATCH v3 08/26] KVM: x86: Unexport LAPIC's switch_to_{hv,sw}_timer() helpers Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 09/26] KVM: x86: Remove defunct pre_block/post_block kvm_x86_ops hooks Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 10/26] KVM: SVM: Signal AVIC doorbell iff vCPU is in guest mode Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 11/26] KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIs Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 12/26] KVM: SVM: Remove unnecessary APICv/AVIC update in vCPU unblocking path Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 13/26] KVM: SVM: Use kvm_vcpu_is_blocking() in AVIC load to handle preemption Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 14/26] KVM: SVM: Skip AVIC and IRTE updates when loading blocking vCPU Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 15/26] iommu/amd: KVM: SVM: Use pCPU to infer IsRun state for IRTE Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 16/26] KVM: VMX: Don't do full kick when triggering posted interrupt "fails" Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 17/26] KVM: VMX: Wake vCPU when delivering posted IRQ even if vCPU == this vCPU Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 18/26] KVM: VMX: Pass desired vector instead of bool for triggering posted IRQ Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 19/26] KVM: VMX: Fold fallback path into triggering posted IRQ helper Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 20/26] KVM: VMX: Don't do full kick when handling posted interrupt wakeup Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 21/26] KVM: SVM: Drop AVIC's intermediate avic_set_running() helper Sean Christopherson
2021-12-08 14:43 ` Paolo Bonzini
2021-12-08 15:03 ` Maxim Levitsky
2021-12-08 15:43 ` Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 22/26] KVM: SVM: Move svm_hardware_setup() and its helpers below svm_x86_ops Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 23/26] KVM: SVM: Nullify vcpu_(un)blocking() hooks if AVIC is disabled Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 24/26] KVM: x86: Skip APICv update if APICv is disable at the module level Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 25/26] KVM: x86: Drop NULL check on kvm_x86_ops.check_apicv_inhibit_reasons Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 26/26] KVM: x86: Unexport __kvm_request_apicv_update() Sean Christopherson
2021-12-08 9:04 ` [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul Paolo Bonzini
2021-12-08 14:51 ` Paolo Bonzini
2021-12-08 23:00 ` Maxim Levitsky
2021-12-08 23:16 ` Maxim Levitsky
2021-12-08 23:34 ` Maxim Levitsky
2021-12-09 0:04 ` Sean Christopherson
2021-12-09 6:36 ` Maxim Levitsky
2021-12-09 0:02 ` Sean Christopherson
2021-12-09 14:29 ` Paolo Bonzini
2021-12-09 14:48 ` Maxim Levitsky
2021-12-09 15:45 ` Sean Christopherson [this message]
2021-12-09 16:03 ` Maxim Levitsky
2021-12-09 1:37 ` Sean Christopherson
2021-12-09 6:31 ` Maxim Levitsky
2021-12-08 23:43 ` Sean Christopherson
2021-12-09 6:34 ` Maxim Levitsky
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