FAILED: patch "[PATCH] KVM: SVM: Disable preemption across AVIC load/put during" failed to apply to 5.15-stable tree
Subsystems (3)
[email protected]
maintainerThe patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b652de1e3dfb3b49e539e88a684a68e333e1bd7c Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
Date: Tue, 1 Mar 2022 09:05:09 -0800
Subject: [PATCH] KVM: SVM: Disable preemption across AVIC load/put during
APICv refresh
Disable preemption when loading/putting the AVIC during an APICv refresh. If the vCPU task is preempted and migrated ot a different pCPU, the unprotected avic_vcpu_load() could set the wrong pCPU in the physical ID cache/table.
Pull the necessary code out of avic_vcpu_{,un}blocking() and into a new helper to reduce the probability of introducing this exact bug a third time.
Fixes df7e4827c549 ("KVM: SVM: call avic_vcpu_load/avic_vcpu_put when enabling/disabling AVIC")
Reported-by Maxim Levitsky <[email protected]>
Signed-off-by Sean Christopherson <[email protected]>
Signed-off-by Paolo Bonzini <[email protected]>
arch/x86/kvm/svm/avic.c +55 -46
@@ -616,38 +616,6 @@ static int avic_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)return ret; } -void avic_refresh_apicv_exec_ctrl (struct kvm_vcpu *vcpu) -{ -struct vcpu_svm *svm =to_svm (vcpu); -struct vmcb *vmcb = svm->vmcb01.ptr; -bool activated =kvm_vcpu_apicv_active (vcpu); - -if (!enable_apicv) -return ; - -if (activated) { -/** -* During AVIC temporary deactivation, guest could update -* APIC ID, DFR and LDR registers, which would not be trapped -* by avic_unaccelerated_access_interception(). In this case, -* we need to check and update the AVIC logical APIC ID table -* accordingly before re-activating. -*/ -avic_apicv_post_state_restore (vcpu); - vmcb->control.int_ctl |=AVIC_ENABLE_MASK ; - }else { - vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK ; - } -vmcb_mark_dirty (vmcb,VMCB_AVIC ); - -if (activated) -avic_vcpu_load (vcpu, vcpu->cpu); -else -avic_vcpu_put (vcpu); - -avic_set_pi_irte_mode (vcpu, activated); -} -static void svm_ir_list_del (struct vcpu_svm *svm,struct amd_iommu_pi_data *pi) {unsigned long flags;
@@ -899,7 +867,7 @@ avic_update_iommu_vcpu_affinity(struct kvm_vcpu *vcpu, int cpu, bool r)return ret; } -void avic_vcpu_load (struct kvm_vcpu *vcpu,int cpu) +void __avic_vcpu_load (struct kvm_vcpu *vcpu,int cpu) {u64 entry;/* ID = 0xff (broadcast), ID > 0xff (reserved) */
@@ -936,7 +904,7 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)avic_update_iommu_vcpu_affinity (vcpu, h_physical_id, true); } -void avic_vcpu_put (struct kvm_vcpu *vcpu) +void __avic_vcpu_put (struct kvm_vcpu *vcpu) {u64 entry;struct vcpu_svm *svm =to_svm (vcpu);
@@ -955,13 +923,63 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu)WRITE_ONCE (*(svm->avic_physical_id_cache), entry); } +static void avic_vcpu_load (struct kvm_vcpu *vcpu) +{ +int cpu =get_cpu (); + +WARN_ON (cpu != vcpu->cpu); + +__avic_vcpu_load (vcpu, cpu); + +put_cpu (); +} + +static void avic_vcpu_put (struct kvm_vcpu *vcpu) +{ +preempt_disable (); + +__avic_vcpu_put (vcpu); + +preempt_enable (); +} + +void avic_refresh_apicv_exec_ctrl (struct kvm_vcpu *vcpu) +{ +struct vcpu_svm *svm =to_svm (vcpu); +struct vmcb *vmcb = svm->vmcb01.ptr; +bool activated =kvm_vcpu_apicv_active (vcpu); + +if (!enable_apicv) +return ; + +if (activated) { +/** +* During AVIC temporary deactivation, guest could update +* APIC ID, DFR and LDR registers, which would not be trapped +* by avic_unaccelerated_access_interception(). In this case, +* we need to check and update the AVIC logical APIC ID table +* accordingly before re-activating. +*/ +avic_apicv_post_state_restore (vcpu); + vmcb->control.int_ctl |=AVIC_ENABLE_MASK ; + }else { + vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK ; + } +vmcb_mark_dirty (vmcb,VMCB_AVIC ); + +if (activated) +avic_vcpu_load (vcpu); +else +avic_vcpu_put (vcpu); + +avic_set_pi_irte_mode (vcpu, activated); +} +void avic_vcpu_blocking (struct kvm_vcpu *vcpu) {if (!kvm_vcpu_apicv_active (vcpu))return ; -preempt_disable (); -/* * Unload the AVIC when the vCPU is about to block, _before_ * the vCPU actually blocks.
@@ -976,21 +994,12 @@ void avic_vcpu_blocking(struct kvm_vcpu *vcpu)* the cause of errata #1235). */ avic_vcpu_put (vcpu); - -preempt_enable (); }void avic_vcpu_unblocking (struct kvm_vcpu *vcpu) { -int cpu; -if (!kvm_vcpu_apicv_active (vcpu))return ; - cpu =get_cpu (); -WARN_ON (cpu != vcpu->cpu); - -avic_vcpu_load (vcpu, cpu); - -put_cpu (); +avic_vcpu_load (vcpu); }
arch/x86/kvm/svm/svm.c +2 -2
@@ -1318,13 +1318,13 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)indirect_branch_prediction_barrier (); }if (kvm_vcpu_apicv_active (vcpu)) -avic_vcpu_load (vcpu, cpu); +__avic_vcpu_load (vcpu, cpu); }static void svm_vcpu_put (struct kvm_vcpu *vcpu) {if (kvm_vcpu_apicv_active (vcpu)) -avic_vcpu_put (vcpu); +__avic_vcpu_put (vcpu);svm_prepare_host_switch (vcpu);
arch/x86/kvm/svm/svm.h +2 -2
@@ -576,8 +576,8 @@ void avic_init_vmcb(struct vcpu_svm *svm);int avic_incomplete_ipi_interception (struct kvm_vcpu *vcpu);int avic_unaccelerated_access_interception (struct kvm_vcpu *vcpu);int avic_init_vcpu (struct vcpu_svm *svm); -void avic_vcpu_load (struct kvm_vcpu *vcpu,int cpu); -void avic_vcpu_put (struct kvm_vcpu *vcpu); +void __avic_vcpu_load (struct kvm_vcpu *vcpu,int cpu); +void __avic_vcpu_put (struct kvm_vcpu *vcpu);void avic_apicv_post_state_restore (struct kvm_vcpu *vcpu);void avic_set_virtual_apic_mode (struct kvm_vcpu *vcpu);void avic_refresh_apicv_exec_ctrl (struct kvm_vcpu *vcpu);