On Wed, Nov 8, 2023 at 2:39 PM Cindy Lu [off-list ref] wrote:

On Wed, Nov 8, 2023 at 11:03 AM Jason Wang [off-list ref] wrote:

quoted

On Tue, Nov 7, 2023 at 2:57 PM Cindy Lu [off-list ref] wrote:

quoted

On Mon, Nov 6, 2023 at 3:30 PM Jason Wang [off-list ref] wrote:

quoted

On Sat, Nov 4, 2023 at 1:17 AM Cindy Lu [off-list ref] wrote:

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VHOST_VDPA_SET_IOMMU_FD: bind the device to iommufd device

VDPA_DEVICE_ATTACH_IOMMUFD_AS: Attach a vdpa device to an iommufd
address space specified by IOAS id.

VDPA_DEVICE_DETACH_IOMMUFD_AS: Detach a vdpa device
from the iommufd address space

Signed-off-by: Cindy Lu <redacted>
---

[...]

quoted

diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index f5c48b61ab62..07e1b2c443ca 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h

@@ -219,4 +219,70 @@
  */
 #define VHOST_VDPA_RESUME              _IO(VHOST_VIRTIO, 0x7E)

+/* vhost_vdpa_set_iommufd
+ * Input parameters:
+ * @iommufd: file descriptor from /dev/iommu; pass -1 to unset
+ * @iommufd_ioasid: IOAS identifier returned from ioctl(IOMMU_IOAS_ALLOC)
+ * Output parameters:
+ * @out_dev_id: device identifier
+ */
+struct vhost_vdpa_set_iommufd {
+       __s32 iommufd;
+       __u32 iommufd_ioasid;
+       __u32 out_dev_id;
+};
+
+#define VHOST_VDPA_SET_IOMMU_FD \
+       _IOW(VHOST_VIRTIO, 0x7F, struct vhost_vdpa_set_iommufd)
+
+/*
+ * VDPA_DEVICE_ATTACH_IOMMUFD_AS -
+ * _IOW(VHOST_VIRTIO, 0x7f, struct vdpa_device_attach_iommufd_as)
+ *
+ * Attach a vdpa device to an iommufd address space specified by IOAS
+ * id.
+ *
+ * Available only after a device has been bound to iommufd via
+ * VHOST_VDPA_SET_IOMMU_FD
+ *
+ * Undo by VDPA_DEVICE_DETACH_IOMMUFD_AS or device fd close.
+ *
+ * @argsz:     user filled size of this data.
+ * @flags:     must be 0.
+ * @ioas_id:   Input the target id which can represent an ioas
+ *             allocated via iommufd subsystem.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct vdpa_device_attach_iommufd_as {
+       __u32 argsz;
+       __u32 flags;
+       __u32 ioas_id;
+};

I think we need to map ioas to vDPA AS, so there should be an ASID
from the view of vDPA?

Thanks

The qemu will have a structure save and  maintain this information,So
I didn't add this
 in kernel，we can add this but maybe only for check?

I meant for example, a simulator has two AS. How can we attach an ioas
to a specific AS with the above uAPI?

Thank>

this   __u32 ioas_id here is alloc from the iommufd system. maybe I
need to change to new name iommuds_asid to
make this more clear
the process in qemu is

1) qemu want to use AS 0 (for example)
2) checking the existing asid. the asid 0 not used before
3 )alloc new asid from iommufd system, get new ioas_id (maybe 3 for example)
qemu will save this relation 3<-->0 in the driver.
4) setting the ioctl VDPA_DEVICE_ATTACH_IOMMUFD_AS to attach new ASID
to the kernel

So if we want to map IOMMUFD AS 3 to VDPA AS 0, how can it be done?

For example I didn't see a vDPA AS parameter in the above uAPI.

vhost_vdpa_set_iommufd has iommufd_ioasid which is obviously not the vDPA AS.

And ioas_id of vdpa_device_attach_iommufd_as (as you explained above)
is not vDPA AS.

Thanks

5） while map the memory， qemu will use ASID 3 to map /umap
and use ASID 0 for legacy mode map/umap

So kernel here will not maintain the ioas_id from iommufd，
and this also make the code strange since there will 2 different asid
for the same AS, maybe we can save these information in the kernel
Thanks
cindy

quoted

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Thanks
Cindy

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+
+#define VDPA_DEVICE_ATTACH_IOMMUFD_AS \
+       _IOW(VHOST_VIRTIO, 0x82, struct vdpa_device_attach_iommufd_as)
+
+/*
+ * VDPA_DEVICE_DETACH_IOMMUFD_AS
+ *
+ * Detach a vdpa device from the iommufd address space it has been
+ * attached to. After it, device should be in a blocking DMA state.
+ *
+ * Available only after a device has been bound to iommufd via
+ * VHOST_VDPA_SET_IOMMU_FD
+ *
+ * @argsz:     user filled size of this data.
+ * @flags:     must be 0.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct vdpa_device_detach_iommufd_as {
+       __u32 argsz;
+       __u32 flags;
+};
+
+#define VDPA_DEVICE_DETACH_IOMMUFD_AS \
+       _IOW(VHOST_VIRTIO, 0x83, struct vdpa_device_detach_iommufd_as)
+
 #endif
--
2.34.3