On 4/11/2025 7:31 PM, Sean Christopherson wrote:
On Fri, Apr 11, 2025, Arun Kodilkar, Sairaj wrote:
On 4/5/2025 1:08 AM, Sean Christopherson wrote:
+int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
+ unsigned int host_irq, uint32_t guest_irq,
+ struct kvm_kernel_irq_routing_entry *new)
{
struct kvm_kernel_irq_routing_entry *e;
struct kvm_irq_routing_table *irq_rt;
bool enable_remapped_mode = true;
+ bool set = !!new;
int idx, ret = 0;
if (!kvm_arch_has_assigned_device(kvm) || !kvm_arch_has_irq_bypass())
@@ -925,6 +919,8 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
if (e->type != KVM_IRQ_ROUTING_MSI)
continue;
+ WARN_ON_ONCE(new && memcmp(e, new, sizeof(*new)));
+
Hi Sean,
In kvm_irq_routing_update() function, its possible that there are
multiple entries in the `kvm_irq_routing_table`,
Not if one of them is an MSI. In setup_routing_entry():
/*
* Do not allow GSI to be mapped to the same irqchip more than once.
* Allow only one to one mapping between GSI and non-irqchip routing.
*/
hlist_for_each_entry(ei, &rt->map[gsi], link)
if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
ue->u.irqchip.irqchip == ei->irqchip.irqchip)
return -EINVAL;
and `irqfd_update()` ends up setting up the new entry type to 0 instead of
copying the entry.
if (n_entries == 1)
irqfd->irq_entry = *e;
else
irqfd->irq_entry.type = 0;
Since irqfd_update() did not copy the entry to irqfd->entries, the "new"
will not match entry "e" obtained from irq_rt, which can trigger a false
WARN_ON.
And since there can only be one MSI, if there are multiple routing entries, then
the WARN won't be reached thanks to the continue that's just above:
if (e->type != KVM_IRQ_ROUTING_MSI)
continue;
Thanks.. I understand it now. I did not see complete code hence the
confusion. Sorry about that.
Regards
Sairaj kodilkar
