From 53b7ca1a359389276c76fbc9e1009d8626a17e40 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 22 Nov 2021 19:43:11 -0500 Subject: [PATCH] KVM: x86: Use a stable condition around all VT-d PI paths Currently, checks for whether VT-d PI can be used refer to the current status of the feature in the current vCPU; or they more or less pick vCPU 0 in case a specific vCPU is not available. However, these checks do not attempt to synchronize with changes to the IRTE. In particular, there is no path that updates the IRTE when APICv is re-activated on vCPU 0; and there is no path to wakeup a CPU that has APICv disabled, if the wakeup occurs because of an IRTE that points to a posted interrupt. To fix this, always go through the VT-d PI path as long as there are assigned devices and APICv is available on both the host and the VM side. Since the relevant condition was copied over three times, take the hint and factor it into a separate function. Suggested-by: Sean Christopherson Cc: stable@vger.kernel.org Reviewed-by: Sean Christopherson Reviewed-by: Maxim Levitsky Reviewed-by: David Matlack Message-Id: <20211123004311.2954158-5-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/posted_intr.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 5f81ef0..1c94783 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -5,6 +5,7 @@ #include #include "lapic.h" +#include "irq.h" #include "posted_intr.h" #include "trace.h" #include "vmx.h" @@ -77,13 +78,18 @@ after_clear_sn: pi_set_on(pi_desc); } +static bool vmx_can_use_vtd_pi(struct kvm *kvm) +{ + return irqchip_in_kernel(kvm) && enable_apicv && + kvm_arch_has_assigned_device(kvm) && + irq_remapping_cap(IRQ_POSTING_CAP); +} + void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) { struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); - if (!kvm_arch_has_assigned_device(vcpu->kvm) || - !irq_remapping_cap(IRQ_POSTING_CAP) || - !kvm_vcpu_apicv_active(vcpu)) + if (!vmx_can_use_vtd_pi(vcpu->kvm)) return; /* Set SN when the vCPU is preempted */ @@ -141,9 +147,7 @@ int pi_pre_block(struct kvm_vcpu *vcpu) struct pi_desc old, new; struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); - if (!kvm_arch_has_assigned_device(vcpu->kvm) || - !irq_remapping_cap(IRQ_POSTING_CAP) || - !kvm_vcpu_apicv_active(vcpu)) + if (!vmx_can_use_vtd_pi(vcpu->kvm)) return 0; WARN_ON(irqs_disabled()); @@ -270,9 +274,7 @@ int pi_update_irte(struct kvm *kvm, unsigned int host_irq, uint32_t guest_irq, struct vcpu_data vcpu_info; int idx, ret = 0; - if (!kvm_arch_has_assigned_device(kvm) || - !irq_remapping_cap(IRQ_POSTING_CAP) || - !kvm_vcpu_apicv_active(kvm->vcpus[0])) + if (!vmx_can_use_vtd_pi(kvm)) return 0; idx = srcu_read_lock(&kvm->irq_srcu); -- 2.7.4