IMS supports an implementation specific cookie that is associated
with each interrupt. By default the IMS interrupt allocation backend
will assign a default cookie to a new interrupt instance.
Add support for a virtual device driver to set the interrupt instance
specific cookie. For example, the virtual device driver may intercept
the guest's MMIO write that configuresa a new PASID for a particular
interrupt. Calling vfio_pci_ims_set_cookie() with the new PASID value
as IMS cookie enables subsequent interrupts to be allocated with
accurate data.
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
---
No changes since RFC V2.
drivers/vfio/pci/vfio_pci_intrs.c | 53 +++++++++++++++++++++++++++++++
include/linux/vfio_pci_core.h | 3 ++
2 files changed, 56 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 32ebc8fec4c4..5dc22dd9390e 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -1188,6 +1188,59 @@ int vfio_pci_ims_hwirq(struct vfio_pci_intr_ctx *intr_ctx, unsigned int vector)
}
EXPORT_SYMBOL_GPL(vfio_pci_ims_hwirq);
+/*
+ * vfio_pci_ims_set_cookie() - Set unique cookie for vector.
+ * @intr_ctx: Interrupt context.
+ * @vector: Vector.
+ * @icookie: New cookie for @vector.
+ *
+ * When new IMS interrupt is allocated for @vector it will be
+ * assigned @icookie.
+ */
+int vfio_pci_ims_set_cookie(struct vfio_pci_intr_ctx *intr_ctx,
+ unsigned int vector,
+ union msi_instance_cookie *icookie)
+{
+ struct vfio_pci_irq_ctx *ctx;
+ int ret = -EINVAL;
+
+ mutex_lock(&intr_ctx->igate);
+
+ if (!intr_ctx->ims_backed_irq)
+ goto out_unlock;
+
+ ctx = vfio_irq_ctx_get(intr_ctx, vector);
+ if (ctx) {
+ if (WARN_ON_ONCE(ctx->emulated)) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ ctx->icookie = *icookie;
+ ret = 0;
+ goto out_unlock;
+ }
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
+ if (!ctx) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ ctx->icookie = *icookie;
+ ret = xa_insert(&intr_ctx->ctx, vector, ctx, GFP_KERNEL_ACCOUNT);
+ if (ret) {
+ kfree(ctx);
+ goto out_unlock;
+ }
+
+ ret = 0;
+
+out_unlock:
+ mutex_unlock(&intr_ctx->igate);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_pci_ims_set_cookie);
+
int vfio_pci_set_irqs_ioctl(struct vfio_pci_intr_ctx *intr_ctx, uint32_t flags,
unsigned int index, unsigned int start,
unsigned int count, void *data)
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index dbc77839ef26..b989b533e852 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -181,6 +181,9 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_intr_ctx *intr_ctx, uint32_t flags,
unsigned int index, unsigned int start,
unsigned int count, void *data);
int vfio_pci_ims_hwirq(struct vfio_pci_intr_ctx *intr_ctx, unsigned int vector);
+int vfio_pci_ims_set_cookie(struct vfio_pci_intr_ctx *intr_ctx,
+ unsigned int vector,
+ union msi_instance_cookie *icookie);
void vfio_pci_send_signal(struct vfio_pci_intr_ctx *intr_ctx, unsigned int vector);
int vfio_pci_set_emulated(struct vfio_pci_intr_ctx *intr_ctx,
unsigned int start, unsigned int count);
--
2.34.1
