> -----Original Message-----
> From: Eric Auger <[email protected]>
> Sent: 05 February 2026 08:33
> To: Shameer Kolothum Thodi <[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 v4 3/5] hw/arm/smmuv3-accel: Allocate vEVENTQ for
> accelerated SMMUv3 devices
> 
> External email: Use caution opening links or attachments
> 
> 
> Hi Shameer,
> 
> On 2/4/26 8:00 PM, Shameer Kolothum wrote:
> > From: Nicolin Chen <[email protected]>
> >
> > When the guest enables the Event Queue and a vIOMMU is present, allocate
> a
> > vEVENTQ object so that host-side events related to the vIOMMU can be
> > received and propagated back to the guest.
> >
> > For cold-plugged devices using SMMUv3 acceleration, the vIOMMU is
> created
> > before the guest boots. In this case, the vEVENTQ is allocated when the
> > guest writes to SMMU_CR0 and sets EVENTQEN = 1.
> >
> > If no cold-plugged device exists at boot (i.e. no vIOMMU initially), the
> > vEVENTQ is allocated when a vIOMMU is created, i.e. during the first
> > device hot-plug.
> >
> > Event read and propagation will be added in a later patch.
> >
> > Signed-off-by: Nicolin Chen <[email protected]>
> > Tested-by: Nicolin Chen <[email protected]>
> > Reviewed-by: Eric Auger <[email protected]>
> > Signed-off-by: Shameer Kolothum <[email protected]>
> > ---
> >  hw/arm/smmuv3-accel.c | 61
> +++++++++++++++++++++++++++++++++++++++++--
> >  hw/arm/smmuv3-accel.h |  6 +++++
> >  hw/arm/smmuv3.c       |  4 +++
> >  3 files changed, 69 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c
> > index c19c526fca..2ca0d1deac 100644
> > --- a/hw/arm/smmuv3-accel.c
> > +++ b/hw/arm/smmuv3-accel.c
> > @@ -390,6 +390,19 @@ bool
> smmuv3_accel_issue_inv_cmd(SMMUv3State *bs, void *cmd, SMMUDevice
> *sdev,
> >                     sizeof(Cmd), &entry_num, cmd, errp);
> >  }
> >
> > +static void smmuv3_accel_free_veventq(SMMUv3AccelState *accel)
> > +{
> > +    IOMMUFDVeventq *veventq = accel->veventq;
> > +
> > +    if (!veventq) {
> > +        return;
> > +    }
> > +    close(veventq->veventq_fd);
> > +    iommufd_backend_free_id(accel->viommu->iommufd, veventq-
> >veventq_id);
> > +    g_free(veventq);
> > +    accel->veventq = NULL;
> > +}
> > +
> >  static void smmuv3_accel_free_viommu(SMMUv3AccelState *accel)
> >  {
> >      IOMMUFDViommu *viommu = accel->viommu;
> > @@ -397,6 +410,7 @@ static void
> smmuv3_accel_free_viommu(SMMUv3AccelState *accel)
> >      if (!viommu) {
> >          return;
> >      }
> > +    smmuv3_accel_free_veventq(accel);
> >      iommufd_backend_free_id(viommu->iommufd, accel->bypass_hwpt_id);
> >      iommufd_backend_free_id(viommu->iommufd, accel->abort_hwpt_id);
> >      iommufd_backend_free_id(viommu->iommufd, accel->viommu-
> >viommu_id);
> > @@ -404,6 +418,41 @@ static void
> smmuv3_accel_free_viommu(SMMUv3AccelState *accel)
> >      accel->viommu = NULL;
> >  }
> >
> > +bool smmuv3_accel_alloc_veventq(SMMUv3State *s, Error **errp)
> > +{
> > +    SMMUv3AccelState *accel = s->s_accel;
> > +    IOMMUFDVeventq *veventq;
> > +    uint32_t veventq_id;
> > +    uint32_t veventq_fd;
> 
> you need to check !accel because in case of non accelerated SMMU it
> sigsevs in smmu_writel/smmuv3_accel_alloc_veventq path

Oops. Right. Will add.

Thanks,
Shameer

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