Re: [PATCH v5 2/2] vfio/cdx: add interrupt support
From: Gupta, Nipun
Date: Mon Apr 22 2024 - 08:56:07 EST
On 4/20/2024 4:01 AM, Alex Williamson wrote:
On Tue, 26 Mar 2024 09:38:04 +0530
Nipun Gupta <nipun.gupta@xxxxxxx> wrote:
Support the following ioctls for CDX devices:
- VFIO_DEVICE_GET_IRQ_INFO
- VFIO_DEVICE_SET_IRQS
This allows user to set an eventfd for cdx device interrupts and
trigger this interrupt eventfd from userspace.
All CDX device interrupts are MSIs. The MSIs are allocated from the
CDX-MSI domain.
Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@xxxxxxx>
---
Changes v4->v5:
- Rebased on 6.9-rc1
<snip>
+
+ for (i = start; i < start + count; i++) {
+ if (!vdev->cdx_irqs[i].trigger)
+ continue;
+ if (flags & VFIO_IRQ_SET_DATA_NONE)
+ eventfd_signal(vdev->cdx_irqs[i].trigger);
Typically DATA_BOOL support is also added here.
Sure. will add it.
+ }
+
+ return 0;
+}
+
+int vfio_cdx_set_irqs_ioctl(struct vfio_cdx_device *vdev,
+ u32 flags, unsigned int index,
+ unsigned int start, unsigned int count,
+ void *data)
+{
+ if (flags & VFIO_IRQ_SET_ACTION_TRIGGER)
+ return vfio_cdx_set_msi_trigger(vdev, index, start,
+ count, flags, data);
+ else
+ return -EINVAL;
+}
+
+/* Free All IRQs for the given device */
+void vfio_cdx_irqs_cleanup(struct vfio_cdx_device *vdev)
+{
+ /*
+ * Device does not support any interrupt or the interrupts
+ * were not configured
+ */
+ if (!vdev->cdx_irqs)
+ return;
+
+ vfio_cdx_set_msi_trigger(vdev, 1, 0, 0, VFIO_IRQ_SET_DATA_NONE, NULL);
@index is passed as 1 here. AFAICT only index zero is supported. The
SET_IRQS ioctl path catches this in
vfio_set_irqs_validate_and_prepare() but it might cause some strange
behavior here if another index were ever added.
Agree, index should be passed as 0 here.
+}
diff --git a/drivers/vfio/cdx/main.c b/drivers/vfio/cdx/main.c
index 9cff8d75789e..f0861a38ae10 100644
--- a/drivers/vfio/cdx/main.c
+++ b/drivers/vfio/cdx/main.c
@@ -61,6 +61,7 @@ static void vfio_cdx_close_device(struct vfio_device *core_vdev)
kfree(vdev->regions);
cdx_dev_reset(core_vdev->dev);
+ vfio_cdx_irqs_cleanup(vdev);
}
static int vfio_cdx_bm_ctrl(struct vfio_device *core_vdev, u32 flags,
@@ -123,7 +124,7 @@ static int vfio_cdx_ioctl_get_info(struct vfio_cdx_device *vdev,
info.flags |= VFIO_DEVICE_FLAGS_RESET;
info.num_regions = cdx_dev->res_count;
- info.num_irqs = 0;
+ info.num_irqs = cdx_dev->num_msi ? 1 : 0;
return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
}
@@ -152,6 +153,59 @@ static int vfio_cdx_ioctl_get_region_info(struct vfio_cdx_device *vdev,
return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
}
+static int vfio_cdx_ioctl_get_irq_info(struct vfio_cdx_device *vdev,
+ struct vfio_irq_info __user *arg)
+{
+ unsigned long minsz = offsetofend(struct vfio_irq_info, count);
+ struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
+ struct vfio_irq_info info;
+
+ if (copy_from_user(&info, arg, minsz))
+ return -EFAULT;
+
+ if (info.argsz < minsz)
+ return -EINVAL;
+
+ if (info.index >= 1)
+ return -EINVAL;
+
+ info.flags = VFIO_IRQ_INFO_EVENTFD | VFIO_IRQ_INFO_NORESIZE;
+ info.count = cdx_dev->num_msi;
This should return -EINVAL if cdx_dev->num_msi is zero.
Agree. Will add this check.
+
+ return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
+}
+
+static int vfio_cdx_ioctl_set_irqs(struct vfio_cdx_device *vdev,
+ struct vfio_irq_set __user *arg)
+{
+ unsigned long minsz = offsetofend(struct vfio_irq_set, count);
+ struct cdx_device *cdx_dev = to_cdx_device(vdev->vdev.dev);
+ struct vfio_irq_set hdr;
+ size_t data_size = 0;
+ u8 *data = NULL;
+ int ret = 0;
+
+ if (copy_from_user(&hdr, arg, minsz))
+ return -EFAULT;
+
+ ret = vfio_set_irqs_validate_and_prepare(&hdr, cdx_dev->num_msi,
+ 1, &data_size);
+ if (ret)
+ return ret;
+
+ if (data_size) {
+ data = memdup_user(arg->data, data_size);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+ }
+
+ ret = vfio_cdx_set_irqs_ioctl(vdev, hdr.flags, hdr.index,
+ hdr.start, hdr.count, data);
+ kfree(data);
+
+ return ret;
+}
+
static long vfio_cdx_ioctl(struct vfio_device *core_vdev,
unsigned int cmd, unsigned long arg)
{
@@ -164,6 +218,10 @@ static long vfio_cdx_ioctl(struct vfio_device *core_vdev,
return vfio_cdx_ioctl_get_info(vdev, uarg);
case VFIO_DEVICE_GET_REGION_INFO:
return vfio_cdx_ioctl_get_region_info(vdev, uarg);
+ case VFIO_DEVICE_GET_IRQ_INFO:
+ return vfio_cdx_ioctl_get_irq_info(vdev, uarg);
+ case VFIO_DEVICE_SET_IRQS:
+ return vfio_cdx_ioctl_set_irqs(vdev, uarg);
case VFIO_DEVICE_RESET:
return cdx_dev_reset(core_vdev->dev);
default:
diff --git a/drivers/vfio/cdx/private.h b/drivers/vfio/cdx/private.h
index 8e9d25913728..7a8477ae4652 100644
--- a/drivers/vfio/cdx/private.h
+++ b/drivers/vfio/cdx/private.h
@@ -13,6 +13,14 @@ static inline u64 vfio_cdx_index_to_offset(u32 index)
return ((u64)(index) << VFIO_CDX_OFFSET_SHIFT);
}
+struct vfio_cdx_irq {
+ u32 flags;
+ u32 count;
+ int irq_no;
+ struct eventfd_ctx *trigger;
+ char *name;
+};
+
struct vfio_cdx_region {
u32 flags;
u32 type;
@@ -25,6 +33,16 @@ struct vfio_cdx_device {
struct vfio_cdx_region *regions;
u32 flags;
#define BME_SUPPORT BIT(0)
+ struct vfio_cdx_irq *cdx_irqs;
+ u32 irq_count;
+ u32 config_msi;
};
You might want to reorder these to avoid holes in the data structures.
vfio_cdx_irq will have a 4byte hole in the middle, vfio_cdx_device will
have a 4byte hole after flags. config_msi is used as a bool, I'm not
sure why it's defined as a u32. irq_count also holds a value up to 1,
so a u32 might be oversized.
There's clearly latent support here for devices with multiple MSI
vectors, is this just copying vfio-pci-core or will CDX devices have
multiple MSIs? Thanks,
Will reorder structure fields to avoid holes. CDX support multiple MSIs
and 'irq_count' is actually number of MSIs which can be more than 1. We
can replace irq_count to msi_count to avoid confusion.
Thanks,
Nipun
Alex