Arvind R wrote: > On Thu, Mar 11, 2010 at 4:32 PM, Pekka Paalanen <p...@iki.fi> wrote: > >> I'm adding dri-devel@ to CC, since this suggested patch touches >> TTM code, and none of the Nouveau code. TTM patches go via >> dri-de...@. >> >> Thanks. >> >> >>
This is a NAK in its current form. First, At mmap() time, the placement may not be known, and even if it is known, the placement may change. Second, VM_IO is used to avoid including bos in core dumps, and make sure get_user_pages() isn't lazily called on BOs. That would cause the lock inversion prevention to fail. Third, I'm not sure the Xen strategy will work for VM_MIXEDMAP, which may contain both IO- and real pages? Thanks, Thomas >> On Wed, 10 Mar 2010 18:51:21 +0530 >> Arvind R <arvin...@gmail.com> wrote: >> >> >>> Hi, >>> Following is a simple patch that is needed in nouveau to get >>> accelerated X on a Xen dom0 pv_ops kernel. The kernel is jeremy's >>> 2.6.31.6 as of 20100222. The whole gpu tree of nouveau (which is >>> almost the mainline merge), was substituted into the kernel-tree. >>> All components of X (mesa, Xorg-server-7.5, xf86-nouveau, libdrm) >>> used of the same day. >>> >>> Patch: >>> diff -Naur nouveau-kernel.orig/drivers/gpu/drm/ttm/ttm_bo_vm.c >>> nouveau-kernel.new/drivers/gpu/drm/ttm/ttm_bo_vm.c >>> --- nouveau-kernel.orig/drivers/gpu/drm/ttm/ttm_bo_vm.c 2010-01-27 >>> 10:19:28.000000000 +0530 >>> +++ nouveau-kernel.new/drivers/gpu/drm/ttm/ttm_bo_vm.c 2010-03-10 >>> 17:28:59.000000000 +0530 >>> @@ -271,7 +271,10 @@ >>> */ >>> >>> vma->vm_private_data = bo; >>> - vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | >>> VM_DONTEXPAND; >>> + vma->vm_flags |= VM_RESERVED | VM_MIXEDMAP | >>> VM_DONTEXPAND; >>> + if (!((bo->mem.placement & TTM_PL_MASK_MEM) & >>> TTM_PL_FLAG_TT)) >>> + vma->vm_flags |= VM_IO; >>> + vma->vm_page_prot = vma_get_vm_prot(vma->vm_flags); >>> return 0; >>> out_unref: >>> ttm_bo_unref(&bo); >>> >>> > sorry for the typo and other procedural errors. > the last added line should be > + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags) > > >>> This patch is necessary because, in Xen, PFN of a page is >>> virtualised. So physical addresses >>> for DMA programming needs to use the MFN. Xen transparently does >>> the correct translation >>> using the _PAGE_IOMEM prot-bit in the PTE. If the bit is set, >>> then Xen assumes that the backing >>> memory is in the IOMEM space, and PFN equals MFN. If not set, >>> page_to_pfn() returns MFN. >>> >>> The patch enables the ttm_bo_vm_fault() handler to behave >>> correctly under Xen, and has no >>> side-effects on normal (not under Xen) operations. The use of >>> TTM_PL_FLAG_TT in the >>> check assumes that all other placements are backed by device >>> memory or IO. If there are >>> any other placements that use system memory, that flag has to be >>> OR'ed into the check. >>> >>> The above patch has no implications on a normal kernel or a Xen >>> pv_ops kernel booted without >>> the Xen hypervisor. My testing is on a debian-lenny environment >>> on a Core2 processor with >>> nVidia GeForce 9400 GT. >>> > Efficacy of patch: > successful flightgear run on dom0 AND bareboot! > > Arvind R. > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > -- > _______________________________________________ > Dri-devel mailing list > Dri-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/dri-devel > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
