Hi Zhenzhong, On 6/4/24 04:45, Duan, Zhenzhong wrote: > Hi Eric, > >> -----Original Message----- >> From: Eric Auger <eric.au...@redhat.com> >> Subject: Re: [PATCH v6 07/19] vfio/container: Implement >> HostIOMMUDeviceClass::realize() handler >> >> Hi Zhenzhong, >> >> On 6/3/24 08:10, Zhenzhong Duan wrote: >>> Utilize range_get_last_bit() to get host IOMMU address width and >>> package it in HostIOMMUDeviceCaps for query with .get_cap(). >>> >>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com> >>> --- >>> hw/vfio/container.c | 26 ++++++++++++++++++++++++++ >>> 1 file changed, 26 insertions(+) >>> >>> diff --git a/hw/vfio/container.c b/hw/vfio/container.c >>> index c4fca2dfca..48800fe92f 100644 >>> --- a/hw/vfio/container.c >>> +++ b/hw/vfio/container.c >>> @@ -1136,6 +1136,31 @@ static void >> vfio_iommu_legacy_class_init(ObjectClass *klass, void *data) >>> vioc->pci_hot_reset = vfio_legacy_pci_hot_reset; >>> }; >>> >>> +static bool hiod_legacy_vfio_realize(HostIOMMUDevice *hiod, void >> *opaque, >>> + Error **errp) >>> +{ >>> + VFIODevice *vdev = opaque; >>> + /* iova_ranges is a sorted list */ >>> + GList *l = g_list_last(vdev->bcontainer->iova_ranges); >>> + >>> + /* Only support query HOST_IOMMU_DEVICE_CAP_AW_BITS with >> legacy backend */ >> I don't get the comment as HOST_IOMMU_DEVICE_CAP_AW_BITS support >> seems >> to be introduced in [PATCH v6 11/19] backends/iommufd: Implement >> HostIOMMUDeviceClass::get_cap() handler > Sorry about my poor English, I mean legacy backend only support > HOST_IOMMU_DEVICE_CAP_AW_BITS, no other caps. > May be only: > > /* Only support query HOST_IOMMU_DEVICE_CAP_AW_BITS */ no problem. Then I would put this comment in the commit msg instead. Something like "the realize function populates the capabilities. For now only the aw_bits caps is computed".
> >>> + if (l) { >>> + Range *range = l->data; >>> + hiod->caps.aw_bits = range_get_last_bit(range) + 1; >>> + } else { >>> + hiod->caps.aw_bits = 0xff; >> why this value? > 0xff means no limitation on aw_bits from host side. Aw_bits check > should always pass. This could be a case that an old kernel doesn't > support query iova ranges. > > Will add a define like: > > #define HOST_IOMMU_DEVICE_CAP_AW_BITS_MAX 0xff Wouldn't 64 bits be a better choice? Also maybe add a comment explaining that iova_ranges may be void for old kernels that do not support the query? Eric > > Thanks > Zhenzhong > >>> + } >>> + >>> + return true; >>> +} >>> + >>> +static void hiod_legacy_vfio_class_init(ObjectClass *oc, void *data) >>> +{ >>> + HostIOMMUDeviceClass *hioc = HOST_IOMMU_DEVICE_CLASS(oc); >>> + >>> + hioc->realize = hiod_legacy_vfio_realize; >>> +}; >>> + >>> static const TypeInfo types[] = { >>> { >>> .name = TYPE_VFIO_IOMMU_LEGACY, >>> @@ -1144,6 +1169,7 @@ static const TypeInfo types[] = { >>> }, { >>> .name = TYPE_HOST_IOMMU_DEVICE_LEGACY_VFIO, >>> .parent = TYPE_HOST_IOMMU_DEVICE, >>> + .class_init = hiod_legacy_vfio_class_init, >>> } >>> }; >>> >> Thanks >> >> Eric