similar to: [PATCH] virtio: 9p: correctly pass physical address to userspace for high pages

Some virtio device drivers (9p) need to translate high virtual addresses to physical addresses, which are inserted into the virtqueue for processing by userspace. This patch exports the kmap_to_page symbol, so that the affected drivers can be compiled as modules. Signed-off-by: Will Deacon <will.deacon at arm.com> --- mm/highmem.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)

Some virtio device drivers (9p) need to translate high virtual addresses to physical addresses, which are inserted into the virtqueue for processing by userspace. This patch exports the kmap_to_page symbol, so that the affected drivers can be compiled as modules. Signed-off-by: Will Deacon <will.deacon at arm.com> --- mm/highmem.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)

The 9p-virtio transport does zero copy on things larger than 1024 bytes in size. It accomplishes this by returning the physical addresses of pages to the virtio-pci device. At present, the translation is usually a bit shift. However, that approach produces an invalid page address when we read/write to vmalloc buffers, such as those used for Linux kernle modules. This causes QEMU to die printing:

The 9p-virtio transport does zero copy on things larger than 1024 bytes in size. It accomplishes this by returning the physical addresses of pages to the virtio-pci device. At present, the translation is usually a bit shift. However, that approach produces an invalid page address when we read/write to vmalloc buffers, such as those used for Linux kernle modules. This causes QEMU to die printing:

On 12/06/2013 06:14 AM, Will Deacon wrote: > On Wed, Dec 04, 2013 at 08:43:18PM +0000, Richard Yao wrote: >> The 9p-virtio transport does zero copy on things larger than 1024 bytes >> in size. It accomplishes this by returning the physical addresses of >> pages to the virtio-pci device. At present, the translation is usually a >> bit shift. >> >> However,

On 12/06/2013 06:14 AM, Will Deacon wrote: > On Wed, Dec 04, 2013 at 08:43:18PM +0000, Richard Yao wrote: >> The 9p-virtio transport does zero copy on things larger than 1024 bytes >> in size. It accomplishes this by returning the physical addresses of >> pages to the virtio-pci device. At present, the translation is usually a >> bit shift. >> >> However,

On Wed, Dec 04, 2013 at 08:43:18PM +0000, Richard Yao wrote: > The 9p-virtio transport does zero copy on things larger than 1024 bytes > in size. It accomplishes this by returning the physical addresses of > pages to the virtio-pci device. At present, the translation is usually a > bit shift. > > However, that approach produces an invalid page address when we > read/write to

From: Michal Hocko <mhocko at suse.com> b92b1b89a33c ("virtio: force vring descriptors to be allocated from lowmem") tried to exclude highmem pages for descriptors so it cleared __GFP_HIGHMEM from a given gfp mask. The patch also cleared __GFP_HIGH which doesn't make much sense for this fix because __GFP_HIGH only controls access to memory reserves and it doesn't have any

From: Michal Hocko <mhocko at suse.com> b92b1b89a33c ("virtio: force vring descriptors to be allocated from lowmem") tried to exclude highmem pages for descriptors so it cleared __GFP_HIGHMEM from a given gfp mask. The patch also cleared __GFP_HIGH which doesn't make much sense for this fix because __GFP_HIGH only controls access to memory reserves and it doesn't have any

From: John Hubbard <jhubbard at nvidia.com> Hi, This is mostly Jerome's work, converting the block/bio and related areas to call put_user_page*() instead of put_page(). Because I've changed Jerome's patches, in some cases significantly, I'd like to get his feedback before we actually leave him listed as the author (he might want to disown some or all of these). I added a

From: John Hubbard <jhubbard at nvidia.com> Hi, This is mostly Jerome's work, converting the block/bio and related areas to call put_user_page*() instead of put_page(). Because I've changed Jerome's patches, in some cases significantly, I'd like to get his feedback before we actually leave him listed as the author (he might want to disown some or all of these). I added a

On device hot-unplug, 9p/virtio currently will kfree channel while it might still be in use. Of course, it might stay used forever, so it's an extremely ugly hack, but it seems better than use-after-free that we have now. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- net/9p/trans_virtio.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)

On device hot-unplug, 9p/virtio currently will kfree channel while it might still be in use. Of course, it might stay used forever, so it's an extremely ugly hack, but it seems better than use-after-free that we have now. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- net/9p/trans_virtio.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)

Move the gory details of kmap & al into a private header and only document the interfaces which are usable by drivers. Signed-off-by: Thomas Gleixner <tglx at linutronix.de> --- V3: New patch --- include/linux/highmem-internal.h | 174 +++++++++++++++++++++++++ include/linux/highmem.h | 270 ++++++++++++++------------------------- mm/highmem.c | 11 - 3

I have a PCI device which can perform bus master DMA. I developed a PCI device driver which can allocate DMA buffer and provide mmap operation to map the I/O and DMA buffer to user space. The PCI device driver works well under Linux 2.6.20. However it brokes under XEN 3.0.4. It appears that mmap map to the wrong memory. remap_pfn_range in mmap function return no error when it is used to map

On Thu, Mar 12, 2015 at 11:54:10AM +1030, Rusty Russell wrote: > "Michael S. Tsirkin" <mst at redhat.com> writes: > > On device hot-unplug, 9p/virtio currently will kfree channel while > > it might still be in use. > > > > Of course, it might stay used forever, so it's an extremely ugly hack, > > but it seems better than use-after-free that we

On Thu, Mar 12, 2015 at 11:54:10AM +1030, Rusty Russell wrote: > "Michael S. Tsirkin" <mst at redhat.com> writes: > > On device hot-unplug, 9p/virtio currently will kfree channel while > > it might still be in use. > > > > Of course, it might stay used forever, so it's an extremely ugly hack, > > but it seems better than use-after-free that we

On Fri, Apr 13, 2018 at 12:30:24PM +0800, Jason Wang wrote: > On 2018?04?01? 22:12, Tiwei Bie wrote: > > Hello everyone, > > > > This RFC implements packed ring support for virtio driver. > > > > The code was tested with DPDK vhost (testpmd/vhost-PMD) implemented > > by Jens at http://dpdk.org/ml/archives/dev/2018-January/089417.html > > Minor changes

On Fri, Apr 13, 2018 at 12:30:24PM +0800, Jason Wang wrote: > On 2018?04?01? 22:12, Tiwei Bie wrote: > > Hello everyone, > > > > This RFC implements packed ring support for virtio driver. > > > > The code was tested with DPDK vhost (testpmd/vhost-PMD) implemented > > by Jens at http://dpdk.org/ml/archives/dev/2018-January/089417.html > > Minor changes

Hi all, this patch series enables xen-swiotlb on arm and arm64. It has been heavily reworked compared to the previous versions in order to achieve better performances and to address review comments. We are not using dma_mark_clean to ensure coherency anymore. We call the platform implementation of map_page and unmap_page. We assume that dom0 has been mapped 1:1 (physical address == machine