Hi Yi,
On 4/6/20 9:12 AM, Liu, Yi L wrote:
> 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.
OK I get it. However in memory_region_init_io(), you also pass the
owner, eg. region so I think you could do the same. no?
Thanks
Eric
>
> +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
>
