[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Re: [Patch RFC] ttm: nouveau accelerated on Xen pv-ops kernel
On 03/12/2010 01:45 PM, Arvind R wrote: > On Thu, Mar 11, 2010 at 4:32 PM, Pekka Paalanen <pq@xxxxxx> 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-devel@. >> >> Thanks. >> >> >> On Wed, 10 Mar 2010 18:51:21 +0530 >> Arvind R <arvino55@xxxxxxxxx> 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! > Jeremy, will you be merging this patch into any of the xen/stable-* branches any time soon? Thanks, joanna. Attachment:
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