Hi Eric,
> From: Auger Eric <eric.auger@xxxxxxxxxx>
> Sent: Wednesday, April 1, 2020 3:51 PM
> To: Liu, Yi L <yi.l.liu@xxxxxxxxx>; qemu-devel@xxxxxxxxxx;
> Subject: Re: [PATCH v2 09/22] vfio/common: init HostIOMMUContext per-container
>
> Hi Yi,
>
> On 3/30/20 6:24 AM, Liu Yi L wrote:
> > In this patch, QEMU firstly gets iommu info from kernel to check the
> > supported capabilities by a VFIO_IOMMU_TYPE1_NESTING iommu. And inits
> > HostIOMMUContet instance.
> >
> > Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> > Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > Cc: Peter Xu <peterx@xxxxxxxxxx>
> > Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> > Cc: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
> > Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > ---
> > hw/vfio/common.c | 99
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 99 insertions(+)
> >
> > diff --git a/hw/vfio/common.c b/hw/vfio/common.c index
> > 5f3534d..44b142c 100644
> > --- a/hw/vfio/common.c
> > +++ b/hw/vfio/common.c
> > @@ -1226,10 +1226,89 @@ static int
> vfio_host_iommu_ctx_pasid_free(HostIOMMUContext *iommu_ctx,
> > return 0;
> > }
> >
> > +/**
> > + * Get iommu info from host. Caller of this funcion should free
> > + * the memory pointed by the returned pointer stored in @info
> > + * after a successful calling when finished its usage.
> > + */
> > +static int vfio_get_iommu_info(VFIOContainer *container,
> > + struct vfio_iommu_type1_info **info) {
> > +
> > + size_t argsz = sizeof(struct vfio_iommu_type1_info);
> > +
> > + *info = g_malloc0(argsz);
> > +
> > +retry:
> > + (*info)->argsz = argsz;
> > +
> > + if (ioctl(container->fd, VFIO_IOMMU_GET_INFO, *info)) {
> > + g_free(*info);
> > + *info = NULL;
> > + return -errno;
> > + }
> > +
> > + if (((*info)->argsz > argsz)) {
> > + argsz = (*info)->argsz;
> > + *info = g_realloc(*info, argsz);
> > + goto retry;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static struct vfio_info_cap_header *
> > +vfio_get_iommu_info_cap(struct vfio_iommu_type1_info *info, uint16_t
> > +id) {
> > + struct vfio_info_cap_header *hdr;
> > + void *ptr = info;
> > +
> > + if (!(info->flags & VFIO_IOMMU_INFO_CAPS)) {
> > + return NULL;
> > + }
> > +
> > + for (hdr = ptr + info->cap_offset; hdr != ptr; hdr = ptr + hdr->next) {
> > + if (hdr->id == id) {
> > + return hdr;
> > + }
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +static int vfio_get_nesting_iommu_cap(VFIOContainer *container,
> > + struct vfio_iommu_type1_info_cap_nesting
> > +*cap_nesting) {
> > + struct vfio_iommu_type1_info *info;
> > + struct vfio_info_cap_header *hdr;
> > + struct vfio_iommu_type1_info_cap_nesting *cap;
> > + int ret;
> > +
> > + ret = vfio_get_iommu_info(container, &info);
> > + if (ret) {
> > + return ret;
> > + }
> > +
> > + hdr = vfio_get_iommu_info_cap(info,
> > + VFIO_IOMMU_TYPE1_INFO_CAP_NESTING);
> > + if (!hdr) {
> > + g_free(info);
> > + return -errno;
> > + }
> > +
> > + cap = container_of(hdr,
> > + struct vfio_iommu_type1_info_cap_nesting, header);
> > + *cap_nesting = *cap;
> > +
> > + g_free(info);
> > + return 0;
> > +}
> > +
> > static int vfio_init_container(VFIOContainer *container, int group_fd,
> > Error **errp) {
> > int iommu_type, ret;
> > + uint64_t flags = 0;
> >
> > iommu_type = vfio_get_iommu_type(container, errp);
> > if (iommu_type < 0) {
> > @@ -1257,6 +1336,26 @@ static int vfio_init_container(VFIOContainer
> *container, int group_fd,
> > return -errno;
> > }
> >
> > + if (iommu_type == VFIO_TYPE1_NESTING_IOMMU) {
> > + struct vfio_iommu_type1_info_cap_nesting nesting = {
> > + .nesting_capabilities = 0x0,
> > + .stage1_formats = 0, };
> > +
> > + ret = vfio_get_nesting_iommu_cap(container, &nesting);
> > + if (ret) {
> > + error_setg_errno(errp, -ret,
> > + "Failed to get nesting iommu cap");
> > + return ret;
> > + }
> > +
> > + flags |= (nesting.nesting_capabilities & VFIO_IOMMU_PASID_REQS) ?
> > + HOST_IOMMU_PASID_REQUEST : 0;
> I still don't get why you can't transform your iommu_ctx into a pointer and do
> container->iommu_ctx = g_new0(HostIOMMUContext, 1);
> then
> host_iommu_ctx_init(container->iommu_ctx, flags);
>
> looks something similar to (hw/vfio/common.c). You may not even need to use a
> derived VFIOHostIOMMUContext object (As only VFIO does use that object)? Only
> the ops do change, no new field?
> region->mem = g_new0(MemoryRegion, 1);
> memory_region_init_io(region->mem, obj, &vfio_region_ops,
> region, name, region->size);
In this way, the vfio hook can easily get the VFIOContainer from
HostIOMMUContext when call in the hook provided by vfio. e.g. the
one below.
+static int vfio_host_iommu_ctx_pasid_alloc(HostIOMMUContext *iommu_ctx,
+ uint32_t min, uint32_t max,
+ uint32_t *pasid)
+{
+ VFIOContainer *container = container_of(iommu_ctx,
+ VFIOContainer, iommu_ctx);
Regards,
Yi Liu
