On Sun, Apr 9, 2023 at 5:30 PM Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote: > > Am 09.04.23 um 16:44 schrieb Bas Nieuwenhuizen: > > We need to introduce a new version of the info struct because > > libdrm_amdgpu forgot any versioning info in amdgpu_query_hw_ip_info > > so the mesa<->libdrm_amdgpu interface can't handle increasing the > > size. > > Those are not forgotten, but simply unnecessary. > > The size of the input output structures are given to the IOCTL in bytes > and additional bytes should be filled with zeros. At the ioctl side, yes, but it is libdrm_amdgpu filling in the size, while passing in the struct directly from the client (mesa or whatever). So if we have new libdrm_amdgpu and old mesa, then mesa allocates N bytes on the stack and libdrm_amdgpu happily tells the kernel in the ioctl "this struct is N+8 bytes long" which would cause corruption? - Bas > > So you should be able to extend the structures at the end without > breaking anything. > > Regards, > Christian. > > > > > This info would be used by radv to figure out when we need to > > split a submission into multiple submissions. radv currently has > > a limit of 192 which seems to work for most gfx submissions, but > > is way too high for e.g. compute or sdma. > > > > Because the kernel handling is just fine we can just use the v2 > > everywhere and have the return_size do the versioning for us, > > with userspace interpreting 0 as unknown. > > > > Userspace implementation: > > https://gitlab.freedesktop.org/bnieuwenhuizen/drm/-/tree/ib-rejection > > https://gitlab.freedesktop.org/bnieuwenhuizen/mesa/-/tree/ib-rejection > > > > Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2498 > > Signed-off-by: Bas Nieuwenhuizen <bas@xxxxxxxxxxxxxxxxxxx> > > Cc: David Airlie <airlied@xxxxxxxxx> > > --- > > drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 7 ++++-- > > include/uapi/drm/amdgpu_drm.h | 29 +++++++++++++++++++++++++ > > 2 files changed, 34 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > > index 89689b940493..c7e815c2733e 100644 > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c > > @@ -360,7 +360,7 @@ static int amdgpu_firmware_info(struct drm_amdgpu_info_firmware *fw_info, > > > > static int amdgpu_hw_ip_info(struct amdgpu_device *adev, > > struct drm_amdgpu_info *info, > > - struct drm_amdgpu_info_hw_ip *result) > > + struct drm_amdgpu_info_hw_ip2 *result) > > { > > uint32_t ib_start_alignment = 0; > > uint32_t ib_size_alignment = 0; > > @@ -431,6 +431,7 @@ static int amdgpu_hw_ip_info(struct amdgpu_device *adev, > > return -EINVAL; > > } > > > > + result->max_ibs = UINT_MAX; > > for (i = 0; i < adev->num_rings; ++i) { > > /* Note that this uses that ring types alias the equivalent > > * HW IP exposes to userspace. > > @@ -438,6 +439,8 @@ static int amdgpu_hw_ip_info(struct amdgpu_device *adev, > > if (adev->rings[i]->funcs->type == info->query_hw_ip.type && > > adev->rings[i]->sched.ready) { > > ++num_rings; > > + result->max_ibs = min(result->max_ibs, > > + adev->rings[i]->max_ibs); > > } > > } > > > > @@ -536,7 +539,7 @@ int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file *filp) > > } > > return copy_to_user(out, &ui32, min(size, 4u)) ? -EFAULT : 0; > > case AMDGPU_INFO_HW_IP_INFO: { > > - struct drm_amdgpu_info_hw_ip ip = {}; > > + struct drm_amdgpu_info_hw_ip2 ip = {}; > > int ret; > > > > ret = amdgpu_hw_ip_info(adev, info, &ip); > > diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h > > index b6eb90df5d05..45e5ae546d19 100644 > > --- a/include/uapi/drm/amdgpu_drm.h > > +++ b/include/uapi/drm/amdgpu_drm.h > > @@ -1128,6 +1128,9 @@ struct drm_amdgpu_info_device { > > __u32 enabled_rb_pipes_mask_hi; > > }; > > > > +/* The size of this struct cannot be increased for compatibility reasons, use > > + * struct drm_amdgpu_info_hw_ip2 instead. > > + */ > > struct drm_amdgpu_info_hw_ip { > > /** Version of h/w IP */ > > __u32 hw_ip_version_major; > > @@ -1144,6 +1147,32 @@ struct drm_amdgpu_info_hw_ip { > > __u32 ip_discovery_version; > > }; > > > > +/* The prefix fields of this are intentionally the same as those of > > + * struct drm_amdgpu_info_hw_ip. The struct has a v2 to resolve a lack of > > + * versioning on the libdrm_amdgpu side. > > + */ > > +struct drm_amdgpu_info_hw_ip2 { > > + /** Version of h/w IP */ > > + __u32 hw_ip_version_major; > > + __u32 hw_ip_version_minor; > > + /** Capabilities */ > > + __u64 capabilities_flags; > > + /** command buffer address start alignment*/ > > + __u32 ib_start_alignment; > > + /** command buffer size alignment*/ > > + __u32 ib_size_alignment; > > + /** Bitmask of available rings. Bit 0 means ring 0, etc. */ > > + __u32 available_rings; > > + /** version info: bits 23:16 major, 15:8 minor, 7:0 revision */ > > + __u32 ip_discovery_version; > > + /** The maximum number of IBs one can submit in a single submission > > + * ioctl. (When using gang submit: this is per IP type) > > + */ > > + __u32 max_ibs; > > + /** padding to 64bit for arch differences */ > > + __u32 pad; > > +}; > > + > > struct drm_amdgpu_info_num_handles { > > /** Max handles as supported by firmware for UVD */ > > __u32 uvd_max_handles; >
