On Thu, 21 Nov 2002, [iso-8859-15] José Fonseca wrote: > Leif, > > Attached is the patch to allocate private DMA and ring buffers on the > DDX - the DDX part only. I'll now focus on the DRM part.
I didn't get the attachment, could you send it again? > The code compiles but I'll only be able to test it when the changes on > DRM are also done. I would appreciate if you used those falcon eyes of > yours and see if you notice any mistake! ;-) > > My time is still rather limited. If you want I can stop the snapshots > and commit this to CVS so that we both can hack at this. Sure, that works for me. BTW, I was looking at the code in glint_dri.c and it looks like it is incorrectly using drmAddBufs to allocate the page table. The last parameter is actually agp_start and is only used by DRM(addbufs_[agp,sg]). Passing DRM_RESTRICTED has no effect since that parameter isn't used for DRM(addbufs_pci). The flags parameter (the fourth parameter) is only to specify AGP, SG, or PCI. So I think there's actually a potential security bug in the glint driver. In fact, afaict, the only thing that prevents the page table from being handed out as a DMA buffer by drmDMA is the fact that it's a different order (8K vs. 4K for the DMA buffers), and the gamma Mesa client no longer passes the DRM_DMA_LARGER_OK flag (it's commented out). From what I can tell, all buffers allocated with drmAddBufs go on the dev->dma->buflist, and all of these buffers are mapped by drmMapBufs, so they are all client accesible even if none of the DRM ioctls return the index of a "private" buffer to a client. I think what we need is a way to have multiple buffer lists and map (or not map) each list separately (maybe with a flag to map as shared for client DMA buffers and private for the X server indirect buffers?). As far as the descriptor ring buffer goes, for the PCI case it might make sense to have a DRM wrapper around pci_alloc_consistent for general-purpose PCI DMA memory for drivers to use for things like page tables and ring buffers when agp/pcigart aren't used, since we don't need the extra bookeeping fields in drm_buf_t and drmAddMap only works for AGP or scatter-gather PCI mem. What do you think? -- Leif Delgass http://www.retinalburn.net ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
