An emulated interrupt has an associated eventfd but is
not backed by a hardware interrupt.
Add support for emulated interrupts to the IMS backend
that generally involves avoiding the actions involving
hardware configuration.
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
---
drivers/vfio/pci/vfio_pci_intrs.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index c6b213d52beb..f96d7481094a 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -863,8 +863,8 @@ EXPORT_SYMBOL_GPL(vfio_pci_release_intr_ctx);
/*
* Free the IMS interrupt associated with @ctx.
*
- * For an IMS interrupt the interrupt is freed from the underlying
- * PCI device's IMS domain.
+ * For an emulated interrupt there is nothing to do. For an IMS interrupt
+ * the interrupt is freed from the underlying PCI device's IMS domain.
*/
static void vfio_pci_ims_irq_free(struct vfio_pci_intr_ctx *intr_ctx,
struct vfio_pci_irq_ctx *ctx)
@@ -872,6 +872,9 @@ static void vfio_pci_ims_irq_free(struct vfio_pci_intr_ctx *intr_ctx,
struct vfio_pci_ims *ims = intr_ctx->priv;
struct msi_map irq_map = {};
+ if (ctx->emulated)
+ return;
+
irq_map.index = ctx->ims_id;
irq_map.virq = ctx->virq;
pci_ims_free_irq(ims->pdev, irq_map);
@@ -882,8 +885,8 @@ static void vfio_pci_ims_irq_free(struct vfio_pci_intr_ctx *intr_ctx,
/*
* Allocate a host IMS interrupt for @ctx.
*
- * For an IMS interrupt the interrupt is allocated from the underlying
- * PCI device's IMS domain.
+ * For an emulated interrupt there is nothing to do. For an IMS interrupt
+ * the interrupt is allocated from the underlying PCI device's IMS domain.
*/
static int vfio_pci_ims_irq_alloc(struct vfio_pci_intr_ctx *intr_ctx,
struct vfio_pci_irq_ctx *ctx)
@@ -891,6 +894,9 @@ static int vfio_pci_ims_irq_alloc(struct vfio_pci_intr_ctx *intr_ctx,
struct vfio_pci_ims *ims = intr_ctx->priv;
struct msi_map irq_map = {};
+ if (ctx->emulated)
+ return -EINVAL;
+
irq_map = pci_ims_alloc_irq(ims->pdev, &ctx->icookie, NULL);
if (irq_map.index < 0)
return irq_map.index;
@@ -913,9 +919,11 @@ static int vfio_pci_ims_set_vector_signal(struct vfio_pci_intr_ctx *intr_ctx,
ctx = vfio_irq_ctx_get(intr_ctx, vector);
if (ctx && ctx->trigger) {
- irq_bypass_unregister_producer(&ctx->producer);
- free_irq(ctx->virq, ctx->trigger);
- vfio_pci_ims_irq_free(intr_ctx, ctx);
+ if (!ctx->emulated) {
+ irq_bypass_unregister_producer(&ctx->producer);
+ free_irq(ctx->virq, ctx->trigger);
+ vfio_pci_ims_irq_free(intr_ctx, ctx);
+ }
kfree(ctx->name);
ctx->name = NULL;
eventfd_ctx_put(ctx->trigger);
@@ -945,6 +953,9 @@ static int vfio_pci_ims_set_vector_signal(struct vfio_pci_intr_ctx *intr_ctx,
ctx->trigger = trigger;
+ if (ctx->emulated)
+ return 0;
+
ret = vfio_pci_ims_irq_alloc(intr_ctx, ctx);
if (ret < 0)
goto out_put_eventfd_ctx;
@@ -1078,7 +1089,7 @@ int vfio_pci_ims_init_intr_ctx(struct vfio_device *vdev,
intr_ctx->ops = &vfio_pci_ims_intr_ops;
intr_ctx->priv = ims;
- intr_ctx->supports_emulated = false;
+ intr_ctx->supports_emulated = true;
intr_ctx->ims_backed_irq = true;
return 0;
--
2.34.1
