vfio/pci: Pass eventfd context to IRQ handler

Create a link back to the vfio_pci_core_device on the eventfd context
object to avoid lookups in the interrupt path.  The context is known
valid in the interrupt handler.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240401195406.3720453-2-alex.williamson@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index fb5392b749fff07d248e4eb3afa8392f073366e4..31dbc2d061f3b3bb8c613b6f760a3c8cd27e629c 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -23,11 +23,12 @@
 #include "vfio_pci_priv.h"
 
 struct vfio_pci_irq_ctx {
-       struct eventfd_ctx      *trigger;
-       struct virqfd           *unmask;
-       struct virqfd           *mask;
-       char                    *name;
-       bool                    masked;
+       struct vfio_pci_core_device     *vdev;
+       struct eventfd_ctx              *trigger;
+       struct virqfd                   *unmask;
+       struct virqfd                   *mask;
+       char                            *name;
+       bool                            masked;
        struct irq_bypass_producer      producer;
 };
 
@@ -228,15 +229,11 @@ void vfio_pci_intx_unmask(struct vfio_pci_core_device *vdev)
 
 static irqreturn_t vfio_intx_handler(int irq, void *dev_id)
 {
-       struct vfio_pci_core_device *vdev = dev_id;
-       struct vfio_pci_irq_ctx *ctx;
+       struct vfio_pci_irq_ctx *ctx = dev_id;
+       struct vfio_pci_core_device *vdev = ctx->vdev;
        unsigned long flags;
        int ret = IRQ_NONE;
 
-       ctx = vfio_irq_ctx_get(vdev, 0);
-       if (WARN_ON_ONCE(!ctx))
-               return ret;
-
        spin_lock_irqsave(&vdev->irqlock, flags);
 
        if (!vdev->pci_2_3) {
@@ -282,6 +279,7 @@ static int vfio_intx_enable(struct vfio_pci_core_device *vdev,
 
        ctx->name = name;
        ctx->trigger = trigger;
+       ctx->vdev = vdev;
 
        /*
         * Fill the initial masked state based on virq_disabled.  After
@@ -312,7 +310,7 @@ static int vfio_intx_enable(struct vfio_pci_core_device *vdev,
        vdev->irq_type = VFIO_PCI_INTX_IRQ_INDEX;
 
        ret = request_irq(pdev->irq, vfio_intx_handler,
-                         irqflags, ctx->name, vdev);
+                         irqflags, ctx->name, ctx);
        if (ret) {
                vdev->irq_type = VFIO_PCI_NUM_IRQS;
                kfree(name);
@@ -358,7 +356,7 @@ static void vfio_intx_disable(struct vfio_pci_core_device *vdev)
        if (ctx) {
                vfio_virqfd_disable(&ctx->unmask);
                vfio_virqfd_disable(&ctx->mask);
-               free_irq(pdev->irq, vdev);
+               free_irq(pdev->irq, ctx);
                if (ctx->trigger)
                        eventfd_ctx_put(ctx->trigger);
                kfree(ctx->name);