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2020-08-05virtio_ring: sparse warning fixupMichael S. Tsirkin1-10/+9
virtio_store_mb was built with split ring in mind so it accepts __virtio16 arguments. Packed ring uses __le16 values, so sparse complains. It's just a store with some barriers so let's convert it to a macro, we don't loose too much type safety by doing that. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Cornelia Huck <cohuck@redhat.com>
2019-04-09virtio: Honour 'may_reduce_num' in vring_create_virtqueueCornelia Huck1-1/+1
vring_create_virtqueue() allows the caller to specify via the may_reduce_num parameter whether the vring code is allowed to allocate a smaller ring than specified. However, the split ring allocation code tries to allocate a smaller ring on allocation failure regardless of what the caller specified. This may cause trouble for e.g. virtio-pci in legacy mode, which does not support ring resizing. (The packed ring code does not resize in any case.) Let's fix this by bailing out immediately in the split ring code if the requested size cannot be allocated and may_reduce_num has not been specified. While at it, fix a typo in the usage instructions. Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Reviewed-by: Jens Freimann <jfreimann@redhat.com>
2018-06-07virtio_ring: switch to dma_XX barriers for rpmsgMichael S. Tsirkin1-2/+2
virtio is using barriers to order memory accesses, thus dma_wmb/rmb is a good match. Before [mst@tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename 11392 820 0 12212 2fb4 drivers/virtio/virtio_ring.o After mst@tuck linux]$ size drivers/virtio/virtio_ring.o text data bss dec hex filename 11284 820 0 12104 2f48 drivers/virtio/virtio_ring.o Cc: Ohad Ben-Cohen <ohad@wizery.com> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: linux-remoteproc@vger.kernel.org Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-02virtio: add context flag to find vqsMichael S. Tsirkin1-0/+3
Allows maintaining extra context per vq. For ease of use, passing in NULL is legal and disables the feature for all vqs. Includes fixes by Christian for s390, acked by Cornelia. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-02virtio: Add improved queue allocation APIAndy Lutomirski1-0/+35
This leaves vring_new_virtqueue alone for compatbility, but it adds two new improved APIs: vring_create_virtqueue: Creates a virtqueue backed by automatically allocated coherent memory. (Some day it this could be extended to support non-coherent memory, too, if there ends up being a platform on which it's worthwhile.) __vring_new_virtqueue: Creates a virtqueue with a manually-specified layout. This should allow mic_virtio to work much more cleanly. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-01-12virtio_ring: use virt_store_mbMichael S. Tsirkin1-0/+11
We need a full barrier after writing out event index, using virt_store_mb there seems better than open-coding. As usual, we need a wrapper to account for strong barriers. It's tempting to use this in vhost as well, for that, we'll need a variant of smp_store_mb that works on __user pointers. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2016-01-12virtio_ring: update weak barriers to use virt_xxxMichael S. Tsirkin1-21/+4
virtio ring uses smp_wmb on SMP and wmb on !SMP, the reason for the later being that it might be talking to another kernel on the same SMP machine. This is exactly what virt_xxx barriers do, so switch to these instead of homegrown ifdef hacks. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2016-01-12Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"Michael S. Tsirkin1-4/+19
This reverts commit 9e1a27ea42691429e31f158cce6fc61bc79bb2e9. While that commit optimizes !CONFIG_SMP, it mixes up DMA and SMP concepts, making the code hard to figure out. A better way to optimize this is with the new __smp_XXX barriers. As a first step, go back to full rmb/wmb barriers for !SMP. We switch to __smp_XXX barriers in the next patch. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2015-04-13virtio_ring: Update weak barriers to use dma_wmb/rmbAlexander Duyck1-19/+4
This change makes it so that instead of using smp_wmb/rmb which varies depending on the kernel configuration we can can use dma_wmb/rmb which for most architectures should be equal to or slightly more strict than smp_wmb/rmb. The advantage to this is that these barriers are available to uniprocessor builds as well so the performance should improve under such a configuration. Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-29virtio_ring: change host notification APIHeinz Graalfs1-1/+1
Currently a host kick error is silently ignored and not reflected in the virtqueue of a particular virtio device. Changing the notify API for guest->host notification seems to be one prerequisite in order to be able to handle such errors in the context where the kick is triggered. This patch changes the notify API. The notify function must return a bool return value. It returns false if the host notification failed. Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-07-09virtio: include asm/barrier explicitlyMichael S. Tsirkin1-0/+1
virtio_ring.h uses mb() and friends, make it pull in asm/barrier.h itself, not rely on other headers to do it. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-03-20virtio_ring: expose virtio barriers for use in vringh.Rusty Russell1-0/+57
The host side of ring needs this logic too. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-10-13UAPI: (Scripted) Disintegrate include/linuxDavid Howells1-161/+2
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
2012-09-28virtio-ring: move queue_index to vring_virtqueueJason Wang1-1/+2
Instead of storing the queue index in transport-specific virtio structs, this patch moves them to vring_virtqueue and introduces an helper to get the value. This lets drivers simplify their management and tracing of virtqueues. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12virtio: harsher barriers for rpmsg.Rusty Russell1-0/+1
We were cheating with our barriers; using the smp ones rather than the real device ones. That was fine, until rpmsg came along, which is used to talk to a real device (a non-SMP CPU). Unfortunately, just putting back the real barriers (reverting d57ed95d) causes a performance regression on virtio-pci. In particular, Amos reports netbench's TCP_RR over virtio_net CPU utilization increased up to 35% while throughput went down by up to 14%. By comparison, this branch is in the noise. Reference: https://lkml.org/lkml/2011/12/11/22 Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02virtio: modify vring_init and vring_size to take account of the layout ↵Wang Sheng-Hui1-3/+3
containing *_event_idx Based on the layout description in the comments, take account of the *_event_idx in functions vring_init and vring_size. Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30virtio ring: inline function to check for eventsMichael S. Tsirkin1-0/+14
With the new used_event and avail_event and features, both host and guest need similar logic to check whether events are enabled, so it helps to put the common code in the header. Note that Xen has similar logic for notification hold-off in include/xen/interface/io/ring.h with req_event and req_prod corresponding to event_idx + 1 and new_idx respectively. +1 comes from the fact that req_event and req_prod in Xen start at 1, while event index in virtio starts at 0. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30virtio: event index interfaceMichael S. Tsirkin1-1/+14
Define a new feature bit for the guest and host to utilize an event index (like Xen) instead if a flag bit to enable/disable interrupts and kicks. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30virtio: add full three-clause BSD text to headers.Rusty Russell1-0/+23
It's unclear to me if it's important, but it's obviously causing my technical colleages some headaches and I'd hate such imprecision to slow virtio adoption. I've emailed this to all non-trivial contributors for approval, too. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Ryan Harper <ryanh@us.ibm.com> Acked-by: Anthony Liguori <aliguori@us.ibm.com> Acked-by: Eric Van Hensbergen <ericvh@gmail.com> Acked-by: john cooper <john.cooper@redhat.com> Acked-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
2009-07-30lguest and virtio: cleanup struct definitions to Linux style.Rusty Russell1-8/+4
I've been doing this for years, and akpm picked me up on it about 12 months ago. lguest partly serves as example code, so let's do it Right. Also, remove two unused fields in struct vblk_info in the example launcher. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com>
2009-06-12virtio: indirect ring entries (VIRTIO_RING_F_INDIRECT_DESC)Mark McLoughlin1-0/+5
Add a new feature flag for indirect ring entries. These are ring entries which point to a table of buffer descriptors. The idea here is to increase the ring capacity by allowing a larger effective ring size whereby the ring size dictates the number of requests that may be outstanding, rather than the size of those requests. This should be most effective in the case of block I/O where we can potentially benefit by concurrently dispatching a large number of large requests. Even in the simple case of single segment block requests, this results in a threefold increase in ring capacity. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-06-12virtio: add names to virtqueue struct, mapping from devices to queues.Rusty Russell1-1/+2
Add a linked list of all virtqueues for a virtio device: this helps for debugging and is also needed for upcoming interface change. Also, add a "name" field for clearer debug messages. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-12-30virtio: hand virtio ring alignment as argument to vring_new_virtqueueRusty Russell1-0/+1
This allows each virtio user to hand in the alignment appropriate to their virtio_ring structures. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
2008-12-30virtio: rename 'pagesize' arg to vring_init/vring_sizeRusty Russell1-6/+6
It's really the alignment desired for consumer/producer separation; historically this x86 pagesize, but with PowerPC it'll still be x86 pagesize. And in theory lguest could choose a different value. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-07-25virtio: Add transport feature handling stub for virtio_ring.Rusty Russell1-0/+2
To prepare for virtio_ring transport feature bits, hook in a call in all the users to manipulate them. This currently just clears all the bits, since it doesn't understand any features. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtio: clarify NO_NOTIFY flag usageRusty Russell1-2/+6
The other side (host) can set the NO_NOTIFY flag as an optimization, to say "no need to kick me when you add things". Make it clear that this is advisory only; especially that we should always notify when the ring is full. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtio: Fix vring_init/vring_size to take unsigned longAnthony Liguori1-2/+2
Using unsigned int resulted in silent truncation of the upper 32-bit on x86_64 resulting in an OOPS since the ring was being initialized wrong. Please reconsider my previous patch to just use PAGE_ALIGN(). Open coding this sort of stuff, no matter how simple it seems, is just asking for this sort of trouble. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04virtio: explicit enable_cb/disable_cb rather than callback return.Rusty Russell1-1/+1
It seems that virtio_net wants to disable callbacks (interrupts) before calling netif_rx_schedule(), so we can't use the return value to do so. Rename "restart" to "cb_enable" and introduce "cb_disable" hook: callback now returns void, rather than a boolean. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-11-12virtio: Force use of power-of-two for descriptor ring sizesRusty Russell1-8/+11
The virtio descriptor rings of size N-1 were nicely set up to be aligned to an N-byte boundary. But as Anthony Liguori points out, the free-running indices used by virtio require that the sizes be a power of 2, otherwise we get problems on wrap (demonstrated with lguest). So we replace the clever "2^n-1" scheme with a simple "align to page boundary" scheme: this means that all virtio rings take at least two pages, but it's safer than guessing cache alignment. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-11-12virtio: fix vring_init for 64 bitsAnthony Liguori1-2/+2
This patch fixes a typo in vring_init(). This happens to work today in lguest because the sizeof(struct vring_desc) is 16 and struct vring contains 3 pointers and an unsigned int so on 32-bit sizeof(struct vring_desc) == sizeof(struct vring). However, this is no longer true on 64-bit where the bug is exposed. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2007-10-23Virtio helper routines for a descriptor ringbuffer implementationRusty Russell1-0/+119
These helper routines supply most of the virtqueue_ops for hypervisors which want to use a ring for virtio. Unlike the previous lguest implementation: 1) The rings are variable sized (2^n-1 elements). 2) They have an unfortunate limit of 65535 bytes per sg element. 3) The page numbers are always 64 bit (PAE anyone?) 4) They no longer place used[] on a separate page, just a separate cacheline. 5) We do a modulo on a variable. We could be tricky if we cared. 6) Interrupts and notifies are suppressed using flags within the rings. Users need only get the ring pages and provide a notify hook (KVM wants the guest to allocate the rings, lguest does it sanely). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Dor Laor <dor.laor@qumranet.com>