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Merge branch 'kvm-arm64/misc' into kvmarm/next

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* kvm-arm64/misc:
  : Miscellaneous fixes/cleanups for KVM/arm64
  :
  :  - Avoid GICv4 vLPI configuration when confronted with user error
  :
  :  - Only attempt vLPI configuration when the target routing is an MSI
  :
  :  - Document ordering requirements to avoid aforementioned user error
  KVM: arm64: Tear down vGIC on failed vCPU creation
  KVM: arm64: Document ordering requirements for irqbypass
  KVM: arm64: vgic-v4: Fall back to software irqbypass if LPI not found
  KVM: arm64: vgic-v4: Only WARN for HW IRQ mismatch when unmapping vLPI
  KVM: arm64: vgic-v4: Only attempt vLPI mapping for actual MSIs

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2025-03-19 14:51:15 -07:00
commit 3ed0dc03f6
3 changed files with 32 additions and 8 deletions
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5
Documentation/virt/kvm/devices/arm-vgic-its.rst
View File

@ -126,7 +126,8 @@ KVM_DEV_ARM_VGIC_GRP_ITS_REGS
ITS Restore Sequence:
---------------------
The following ordering must be followed when restoring the GIC and the ITS:
The following ordering must be followed when restoring the GIC, ITS, and
KVM_IRQFD assignments:
a) restore all guest memory and create vcpus
b) restore all redistributors
@ -139,6 +140,8 @@ d) restore the ITS in the following order:
3. Load the ITS table data (KVM_DEV_ARM_ITS_RESTORE_TABLES)
4. Restore GITS_CTLR
e) restore KVM_IRQFD assignments for MSIs
Then vcpus can be started.
ITS Table ABI REV0:

18
arch/arm64/kvm/arm.c
View File

@ -466,7 +466,11 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
if (err)
return err;
return kvm_share_hyp(vcpu, vcpu + 1);
err = kvm_share_hyp(vcpu, vcpu + 1);
if (err)
kvm_vgic_vcpu_destroy(vcpu);
return err;
}
void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
@ -2714,6 +2718,14 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
{
struct kvm_kernel_irqfd *irqfd =
container_of(cons, struct kvm_kernel_irqfd, consumer);
struct kvm_kernel_irq_routing_entry *irq_entry = &irqfd->irq_entry;
/*
* The only thing we have a chance of directly-injecting is LPIs. Maybe
* one day...
*/
if (irq_entry->type != KVM_IRQ_ROUTING_MSI)
return 0;
return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,
&irqfd->irq_entry);
@ -2723,6 +2735,10 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
{
struct kvm_kernel_irqfd *irqfd =
container_of(cons, struct kvm_kernel_irqfd, consumer);
struct kvm_kernel_irq_routing_entry *irq_entry = &irqfd->irq_entry;
if (irq_entry->type != KVM_IRQ_ROUTING_MSI)
return;
kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,
&irqfd->irq_entry);

17
arch/arm64/kvm/vgic/vgic-v4.c
View File

@ -415,7 +415,7 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
struct vgic_irq *irq;
struct its_vlpi_map map;
unsigned long flags;
int ret;
int ret = 0;
if (!vgic_supports_direct_msis(kvm))
return 0;
@ -430,10 +430,15 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
mutex_lock(&its->its_lock);
/* Perform the actual DevID/EventID -> LPI translation. */
ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
irq_entry->msi.data, &irq);
if (ret)
/*
* Perform the actual DevID/EventID -> LPI translation.
*
* Silently exit if translation fails as the guest (or userspace!) has
* managed to do something stupid. Emulated LPI injection will still
* work if the guest figures itself out at a later time.
*/
if (vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
irq_entry->msi.data, &irq))
goto out;
/* Silently exit if the vLPI is already mapped */
@ -512,7 +517,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
if (ret)
goto out;
WARN_ON(!(irq->hw && irq->host_irq == virq));
WARN_ON(irq->hw && irq->host_irq != virq);
if (irq->hw) {
atomic_dec(&irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count);
irq->hw = false;