On Mon, Mar 17, 2025 at 08:38:23AM +0000, Shameerali Kolothum Thodi wrote:
> Hi Nicolin,
>
> > -----Original Message-----
> > From: Nicolin Chen <[email protected]>
> > Sent: Tuesday, March 11, 2025 9:08 PM
> > To: Shameerali Kolothum Thodi <[email protected]>
> > Cc: [email protected]; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]; [email protected]; Linuxarm
> > <[email protected]>; Wangzhou (B) <[email protected]>;
> > jiangkunkun <[email protected]>; Jonathan Cameron
> > <[email protected]>; [email protected]
> > Subject: Re: [RFC PATCH v2 09/20] hw/arm/smmuv3-accel: Add
> > set/unset_iommu_device callback
> >
> > On Tue, Mar 11, 2025 at 02:10:34PM +0000, Shameer Kolothum wrote:
> > > @@ -30,6 +32,185 @@ static SMMUv3AccelDevice
> > *smmuv3_accel_get_dev(SMMUState *s, SMMUPciBus *sbus,
> > > return accel_dev;
> > > }
> > >
> > > +static bool
> > > +smmuv3_accel_dev_attach_viommu(SMMUv3AccelDevice *accel_dev,
> > > + HostIOMMUDeviceIOMMUFD *idev, Error
> > > **errp)
> >
> > With vEVENTQ v9, vDEVICE (vSID) is required to attach a device
> > to a proxy NESTED hwpt (applicable to bypass/abort HWPTs too).
> > So, host_iommu_device_iommufd_attach_hwpt() would fail in this
> > function because vSID isn't ready at this stage. So all those
> > calls should be moved out of the function, then this should be
> > likely "smmuv3_accel_dev_alloc_viommu"?
> >
> > That being said, I don't know when QEMU actually prepare a BDF
> > number for a vfio-pci device. The only place that I see it is
> > ready is at guest-level SMMU installing the Stream Table, i.e.
> > in smmuv3_accel_install_nested_ste().
> > > + /*
> > > + * Attach the bypass STE which means S1 bypass and S2 translate.
> > > + * This is to make sure that the vIOMMU object is now associated
> > > + * with the device and has this STE installed in the host SMMUV3.
> > > + */
> > > + if (!host_iommu_device_iommufd_attach_hwpt(
> > > + idev, viommu->bypass_hwpt_id, errp)) {
> > > + error_report("failed to attach the bypass pagetable");
> > > + goto free_bypass_hwpt;
> > > + }
> >
> > Ditto. We have to postpone this until vdevice is allocated.
>
> Ok. I will take a look based on the vEVENTQ v9 series.
> I guess this Qemu branch of yours is a more representative of the changes
> described
> above?
> https://github.com/nicolinc/qemu/commits/wip/for_iommufd_veventq-v9/
Yes.
Mainly this change:
https://github.com/nicolinc/qemu/commit/d8f496eaf528f1c397f2374a999b8b23fd55c75b
Thanks
Nicolin
