> -----Original Message-----
> From: Eric Auger <[email protected]>
> Sent: 09 December 2025 10:32
> To: Shameer Kolothum <[email protected]>; qemu-
> [email protected]; [email protected]
> Cc: [email protected]; Nicolin Chen <[email protected]>; Nathan
> Chen <[email protected]>; Matt Ochs <[email protected]>; Jason
> Gunthorpe <[email protected]>; [email protected];
> [email protected]; [email protected]; Krishnakant Jaju
> <[email protected]>
> Subject: Re: [PATCH v2 1/4] backends/iommufd: Introduce
> iommufd_backend_alloc_veventq
>
> External email: Use caution opening links or attachments
>
>
> On 12/4/25 10:22 AM, Shameer Kolothum wrote:
> > From: Nicolin Chen <[email protected]>
> >
> > Add a new helper for IOMMU_VEVENTQ_ALLOC ioctl to allocate a virtual
> > event queue (vEVENTQ) for a vIOMMU object.
> >
> > Signed-off-by: Nicolin Chen <[email protected]>
> > Signed-off-by: Shameer Kolothum <[email protected]>
> > ---
> > backends/iommufd.c | 31 +++++++++++++++++++++++++++++++
> > backends/trace-events | 1 +
> > include/system/iommufd.h | 12 ++++++++++++
> > 3 files changed, 44 insertions(+)
> >
> > diff --git a/backends/iommufd.c b/backends/iommufd.c index
> > 718d63f5cf..633aecd525 100644
> > --- a/backends/iommufd.c
> > +++ b/backends/iommufd.c
> > @@ -503,6 +503,37 @@ bool
> iommufd_backend_alloc_vdev(IOMMUFDBackend *be, uint32_t dev_id,
> > return true;
> > }
> >
> > +bool iommufd_backend_alloc_veventq(IOMMUFDBackend *be, uint32_t
> viommu_id,
> > + uint32_t type, uint32_t depth,
> > + uint32_t *out_veventq_id,
> > + uint32_t *out_veventq_fd, Error
> > +**errp) {
> > + int ret;
> > + struct iommu_veventq_alloc alloc_veventq = {
> > + .size = sizeof(alloc_veventq),
> > + .flags = 0,
> > + .type = type,
> > + .veventq_depth = depth,
> > + .viommu_id = viommu_id,
> > + };
> > +
> > + ret = ioctl(be->fd, IOMMU_VEVENTQ_ALLOC, &alloc_veventq);
> > +
> > + trace_iommufd_viommu_alloc_eventq(be->fd, viommu_id, type,
> > + alloc_veventq.out_veventq_id,
> > + alloc_veventq.out_veventq_fd, ret);
> > + if (ret) {
> > + error_setg_errno(errp, errno, "IOMMU_VEVENTQ_ALLOC failed");
> > + return false;
> > + }
> > +
> > + g_assert(out_veventq_id);
> > + g_assert(out_veventq_fd);
> can it happen if the ioctl succeeds?
It can right? If the caller has not provided a valid pointer to return the
values obtained from IOCTL.
Thanks,
Shameer
> > + *out_veventq_id = alloc_veventq.out_veventq_id;
> > + *out_veventq_fd = alloc_veventq.out_veventq_fd;
> > + return true;
> > +}
> > +
> > bool
> host_iommu_device_iommufd_attach_hwpt(HostIOMMUDeviceIOMMUFD
> *idev,
> > uint32_t hwpt_id, Error
> > **errp) { diff --git a/backends/trace-events b/backends/trace-events
> > index 8408dc8701..5afa7a40be 100644
> > --- a/backends/trace-events
> > +++ b/backends/trace-events
> > @@ -23,3 +23,4 @@ iommufd_backend_get_dirty_bitmap(int iommufd,
> > uint32_t hwpt_id, uint64_t iova, u iommufd_backend_invalidate_cache(int
> iommufd, uint32_t id, uint32_t data_type, uint32_t entry_len, uint32_t
> entry_num, uint32_t done_num, uint64_t data_ptr, int ret) " iommufd=%d
> id=%u data_type=%u entry_len=%u entry_num=%u done_num=%u
> data_ptr=0x%"PRIx64" (%d)"
> > iommufd_backend_alloc_viommu(int iommufd, uint32_t dev_id, uint32_t
> type, uint32_t hwpt_id, uint32_t viommu_id, int ret) " iommufd=%d type=%u
> dev_id=%u hwpt_id=%u viommu_id=%u (%d)"
> > iommufd_backend_alloc_vdev(int iommufd, uint32_t dev_id, uint32_t
> viommu_id, uint64_t virt_id, uint32_t vdev_id, int ret) " iommufd=%d
> dev_id=%u viommu_id=%u virt_id=0x%"PRIx64" vdev_id=%u (%d)"
> > +iommufd_viommu_alloc_eventq(int iommufd, uint32_t viommu_id,
> uint32_t type, uint32_t veventq_id, uint32_t veventq_fd, int ret) "
> iommufd=%d viommu_id=%u type=%u veventq_id=%u veventq_fd=%u (%d)"
> > diff --git a/include/system/iommufd.h b/include/system/iommufd.h index
> > aa78bf1e1d..9770ff1484 100644
> > --- a/include/system/iommufd.h
> > +++ b/include/system/iommufd.h
> > @@ -56,6 +56,13 @@ typedef struct IOMMUFDVdev {
> > uint32_t virt_id; /* virtual device ID */ } IOMMUFDVdev;
> >
> > +/* Virtual event queue interface for a vIOMMU */ typedef struct
> > +IOMMUFDVeventq {
> > + IOMMUFDViommu *viommu;
> > + uint32_t veventq_id;
> > + uint32_t veventq_fd;
> > +} IOMMUFDVeventq;
> > +
> > bool iommufd_backend_connect(IOMMUFDBackend *be, Error **errp);
> void
> > iommufd_backend_disconnect(IOMMUFDBackend *be);
> >
> > @@ -86,6 +93,11 @@ bool
> iommufd_backend_alloc_vdev(IOMMUFDBackend *be, uint32_t dev_id,
> > uint32_t viommu_id, uint64_t virt_id,
> > uint32_t *out_vdev_id, Error **errp);
> >
> > +bool iommufd_backend_alloc_veventq(IOMMUFDBackend *be, uint32_t
> viommu_id,
> > + uint32_t type, uint32_t depth,
> > + uint32_t *out_veventq_id,
> > + uint32_t *out_veventq_fd, Error
> > +**errp);
> > +
> > bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be,
> uint32_t hwpt_id,
> > bool start, Error **errp);
> > bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t
> > hwpt_id,
> Eric
