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2020-12-08libvhost-user: make it a meson subprojectMarc-André Lureau
By making libvhost-user a subproject, check it builds standalone (without the global QEMU cflags etc). Note that the library still relies on QEMU include/qemu/atomic.h and linux_headers/. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20201125100640.366523-6-marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-11-12vhost-user: fix VHOST_USER_ADD/REM_MEM_REG truncationStefan Hajnoczi
QEMU currently truncates the mmap_offset field when sending VHOST_USER_ADD_MEM_REG and VHOST_USER_REM_MEM_REG messages. The struct layout looks like this: typedef struct VhostUserMemoryRegion { uint64_t guest_phys_addr; uint64_t memory_size; uint64_t userspace_addr; uint64_t mmap_offset; } VhostUserMemoryRegion; typedef struct VhostUserMemRegMsg { uint32_t padding; /* WARNING: there is a 32-bit hole here! */ VhostUserMemoryRegion region; } VhostUserMemRegMsg; The payload size is calculated as follows when sending the message in hw/virtio/vhost-user.c: msg->hdr.size = sizeof(msg->payload.mem_reg.padding) + sizeof(VhostUserMemoryRegion); This calculation produces an incorrect result of only 36 bytes. sizeof(VhostUserMemRegMsg) is actually 40 bytes. The consequence of this is that the final field, mmap_offset, is truncated. This breaks x86_64 TCG guests on s390 hosts. Other guest/host combinations may get lucky if either of the following holds: 1. The guest memory layout does not need mmap_offset != 0. 2. The host is little-endian and mmap_offset <= 0xffffffff so the truncation has no effect. Fix this by extending the existing 32-bit padding field to 64-bit. Now the padding reflects the actual compiler padding. This can be verified using pahole(1). Also document the layout properly in the vhost-user specification. The vhost-user spec did not document the exact layout. It would be impossible to implement the spec without looking at the QEMU source code. Existing vhost-user frontends and device backends continue to work after this fix has been applied. The only change in the wire protocol is that QEMU now sets hdr.size to 40 instead of 36. If a vhost-user implementation has a hardcoded size check for 36 bytes, then it will fail with new QEMUs. Both QEMU and DPDK/SPDK don't check the exact payload size, so they continue to work. Fixes: f1aeb14b0809e313c74244d838645ed25e85ea63 ("Transmit vhost-user memory regions individually") Cc: Raphael Norwitz <raphael.norwitz@nutanix.com> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20201109174355.1069147-1-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Fixes: f1aeb14b0809 ("Transmit vhost-user memory regions individually") Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
2020-11-03libvhost-user: follow QEMU comment styleStefan Hajnoczi
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20201027173528.213464-2-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-10-23libvhost-user: Allow vu_message_read to be replacedCoiby Xu
Allow vu_message_read to be replaced by one which will make use of the QIOChannel functions. Thus reading vhost-user message won't stall the guest. For slave channel, we still use the default vu_message_read. Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Coiby Xu <coiby.xu@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20200918080912.321299-2-coiby.xu@gmail.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-09-17contrib/: fix some comment spelling errorszhaolichang
I found that there are many spelling errors in the comments of qemu, so I used the spellcheck tool to check the spelling errors and finally found some spelling errors in the contrib folder. Signed-off-by: zhaolichang <zhaolichang@huawei.com> Reviewed-by: Alex Bennee <alex.bennee@linaro.org> Message-Id: <20200917075029.313-11-zhaolichang@huawei.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-06-12Lift max ram slots limit in libvhost-userRaphael Norwitz
Historically, VMs with vhost-user devices could hot-add memory a maximum of 8 times. Now that the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS protocol feature has been added, VMs with vhost-user backends which support this new feature can support a configurable number of ram slots up to the maximum supported by the target platform. This change adds VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS support for backends built with libvhost-user, and increases the number of supported ram slots from 8 to 32. Memory hot-add, hot-remove and postcopy migration were tested with the vhost-user-bridge sample. Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <1588533678-23450-11-git-send-email-raphael.norwitz@nutanix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-06-12Support individual region unmap in libvhost-userRaphael Norwitz
When the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS protocol feature is enabled, on memory hot-unplug qemu will transmit memory regions to remove individually using the new message VHOST_USER_REM_MEM_REG message. With this change, vhost-user backends build with libvhost-user can now unmap individual memory regions when receiving the VHOST_USER_REM_MEM_REG message. Qemu only sends VHOST_USER_REM_MEM_REG messages when the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS feature is negotiated, and support for that feature has not yet been added in libvhost-user, this new functionality is not yet used. Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <1588533678-23450-10-git-send-email-raphael.norwitz@nutanix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-06-12Support adding individual regions in libvhost-userRaphael Norwitz
When the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS is enabled, qemu will transmit memory regions to a backend individually using the new message VHOST_USER_ADD_MEM_REG. With this change vhost-user backends built with libvhost-user can now map in new memory regions when VHOST_USER_ADD_MEM_REG messages are received. Qemu only sends VHOST_USER_ADD_MEM_REG messages when the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS feature is negotiated, and since it is not yet supported in libvhost-user, this new functionality is not yet used. Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <1588533678-23450-9-git-send-email-raphael.norwitz@nutanix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-06-12Support ram slot configuration in libvhost-userRaphael Norwitz
The VHOST_USER_GET_MAX_MEM_SLOTS message allows a vhost-user backend to specify a maximum number of ram slots it is willing to support. This change adds support for libvhost-user to process this message. For now the backend will reply with 8 as the maximum number of regions supported. libvhost-user does not yet support the vhost-user protocol feature VHOST_USER_PROTOCOL_F_CONFIGIRE_MEM_SLOTS, so qemu should never send the VHOST_USER_GET_MAX_MEM_SLOTS message. Therefore this new functionality is not currently used. Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Message-Id: <1588533678-23450-8-git-send-email-raphael.norwitz@nutanix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2020-03-16misc: Replace zero-length arrays with flexible array member (automatic)Philippe Mathieu-Daudé
Description copied from Linux kernel commit from Gustavo A. R. Silva (see [3]): --v-- description start --v-- The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member [1], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being unadvertenly introduced [2] to the Linux codebase from now on. --^-- description end --^-- Do the similar housekeeping in the QEMU codebase (which uses C99 since commit 7be41675f7cb). All these instances of code were found with the help of the following Coccinelle script: @@ identifier s, m, a; type t, T; @@ struct s { ... t m; - T a[0]; + T a[]; }; @@ identifier s, m, a; type t, T; @@ struct s { ... t m; - T a[0]; + T a[]; } QEMU_PACKED; [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=76497732932f [3] https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=17642a2fbd2c1 Inspired-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-27libvhost-user: implement in-band notificationsJohannes Berg
Add support for VHOST_USER_PROTOCOL_F_IN_BAND_NOTIFICATIONS, but as it's not desired by default, don't enable it unless the device implementation opts in by returning it from its protocol features callback. Note that I updated vu_set_vring_err_exec(), but didn't add any sending of the VHOST_USER_SLAVE_VRING_ERR message as there's no write to the err_fd today either. This also adds vu_queue_notify_sync() which can be used to force a synchronous notification if inband notifications are supported. Previously, I had left out the slave->master direction handling of F_REPLY_ACK, this now adds some code to support it as well. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Message-Id: <20200123081708.7817-7-johannes@sipsolutions.net> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-01-23libvhost-user: Fix some memtable remap casesDr. David Alan Gilbert
If a new setmemtable command comes in once the vhost threads are running, it will remap the guests address space and the threads will now be looking in the wrong place. Fortunately we're running this command under lock, so we can update the queue mappings so that threads will look in the new-right place. Note: This doesn't fix things that the threads might be doing without a lock (e.g. a readv/writev!) That's for another time. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-01-23contrib/libvhost-user: Protect slave fd with mutexDr. David Alan Gilbert
In future patches we'll be performing commands on the slave-fd driven by commands on queues, since those queues will be driven by individual threads we need to make sure they don't attempt to use the slave-fd for multiple commands in parallel. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2019-07-04libvhost-user: support many virtqueuesStefan Hajnoczi
Currently libvhost-user is hardcoded to at most 8 virtqueues. The device backend should decide the number of virtqueues, not libvhost-user. This is important for multiqueue device backends where the guest driver needs an accurate number of virtqueues. This change breaks libvhost-user and libvhost-user-glib API stability. There is no stability guarantee yet, so make this change now and update all in-tree library users. This patch touches up vhost-user-blk, vhost-user-gpu, vhost-user-input, vhost-user-scsi, and vhost-user-bridge. If the device has a fixed number of queues that exact number is used. Otherwise the previous default of 8 virtqueues is used. vu_init() and vug_init() can now fail if malloc() returns NULL. I considered aborting with an error in libvhost-user but it should be safe to instantiate new vhost-user instances at runtime without risk of terminating the process. Therefore callers need to handle the vu_init() failure now. vhost-user-blk and vhost-user-scsi duplicate virtqueue index checks that are already performed by libvhost-user. This code would need to be modified to use max_queues but remove it completely instead since it's redundant. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20190626074815.19994-3-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2019-05-29vhost-user: add vhost_user_gpu_set_socket()Marc-André Lureau
Add a new vhost-user message to give a unix socket to a vhost-user backend for GPU display updates. Back when I started that work, I added a new GPU channel because the vhost-user protocol wasn't bidirectional. Since then, there is a vhost-user-slave channel for the slave to send requests to the master. We could extend it with GPU messages. However, the GPU protocol is quite orthogonal to vhost-user, thus I chose to have a new dedicated channel. See vhost-user-gpu.rst for the protocol details. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-id: 20190524130946.31736-2-marcandre.lureau@redhat.com Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2019-05-07QEMU_PACKED: Remove gcc_struct attribute in Windows non x86 targetsCao Jiaxi
gcc_struct is for x86 only, and it generates an warning on ARM64 Clang/MinGW targets. Signed-off-by: Cao Jiaxi <driver1998@foxmail.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Message-id: 20190503003618.10089-1-driver1998@foxmail.com [PMM: dropped the slirp change as slirp is now a submodule] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-03-12libvhost-user: Support tracking inflight I/O in shared memoryXie Yongji
This patch adds support for VHOST_USER_GET_INFLIGHT_FD and VHOST_USER_SET_INFLIGHT_FD message to set/get shared buffer to/from qemu. Then backend can track inflight I/O in this buffer. Signed-off-by: Xie Yongji <xieyongji@baidu.com> Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Message-Id: <20190228085355.9614-5-xieyongji@baidu.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2019-03-12libvhost-user: add vu_queue_unpop()Marc-André Lureau
vhost-user-input will make use of this function to undo some queue pop in case the virtio queue does not have enough room. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20190308140454.32437-11-marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2019-03-12libvhost-user: fix clang enum-conversion warningMarc-André Lureau
Now that the VhostUserMsg.request field is used for both master & slave requests, since commit d84599f56c820d8c1ac9928a76500dcdfbbf194d: contrib/libvhost-user/libvhost-user.c:953:20: error: implicit conversion from enumeration type 'enum VhostUserSlaveRequest' to different enumeration type 'VhostUserRequest' (aka 'enum VhostUserRequest') [-Werror,-Wenum-conversion] .request = VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20190308140454.32437-2-marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-05-24libvhost-user: support host notifierTiwei Bie
This patch introduces the host notifier support in libvhost-user. A new API is added to support setting host notifier for each queue. Signed-off-by: Tiwei Bie <tiwei.bie@intel.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-04-09contrib/libvhost-user: add the protocol feature used for SET/GET messageChangpeng Liu
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-03-20vhost-user: Add VHOST_USER_POSTCOPY_END messageDr. David Alan Gilbert
This message is sent just before the end of postcopy to get the client to stop using userfault since we wont respond to any more requests. It should close userfaultfd so that any other pages get mapped to the backing file automatically by the kernel, since at this point we know we've received everything. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-03-20vhost+postcopy: Transmit 'listen' to slaveDr. David Alan Gilbert
Notify the vhost-user slave on reception of the 'postcopy-listen' event from the source. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-03-20libvhost-user: Open userfaultfdDr. David Alan Gilbert
Open a userfaultfd (on a postcopy_advise) and send it back in the reply to the qemu for it to monitor. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-03-20vhost-user: Add 'VHOST_USER_POSTCOPY_ADVISE' messageDr. David Alan Gilbert
Wire up a notifier to send a VHOST_USER_POSTCOPY_ADVISE message on an incoming advise. Later patches will fill in the behaviour/contents of the message. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-03-20postcopy: Add vhost-user flag for postcopy and check itDr. David Alan Gilbert
Add a vhost feature flag for postcopy support, and use the postcopy notifier to check it before allowing postcopy. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-02-13libvhost-user: Support across-memory-boundary accessYongji Xie
The sg list/indirect descriptor table may be contigious in GPA but not in HVA address space. But libvhost-user wasn't aware of that. This would cause out-of-bounds access. Even a malicious guest could use it to get information from the vhost-user backend. Introduce a plen parameter in vu_gpa_to_va() so we can handle this case, returning the actual mapped length. Signed-off-by: Yongji Xie <xieyongji@baidu.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
2018-01-18contrib/libvhost-user: enable virtio config space messagesChangpeng Liu
Enable VHOST_USER_GET_CONFIG/VHOST_USER_SET_CONFIG messages in libvhost-user library, users can implement their own I/O target based on the library. This enable the virtio config space delivered between QEMU host device and the I/O target. Signed-off-by: Changpeng Liu <changpeng.liu@intel.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-10-12libvhost-user: Support VHOST_USER_SET_SLAVE_REQ_FDDr. David Alan Gilbert
Allow the qemu to pass us a slave fd. We don't do anything with it yet. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20171002191521.15748-5-dgilbert@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
2017-10-12libvhost-user: Update and fix feature and request listsDr. David Alan Gilbert
Update the ProtocolFeature and UserRequest lists to match hw/virtio/vhost-user.c. Fix the text labelling in libvhost-user.c to match the list. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20171002191521.15748-4-dgilbert@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
2017-10-12libvhost-user: vu_queue_startedDr. David Alan Gilbert
Add a vu_queue_started method to complement vu_queue_enabled. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20171002191521.15748-2-dgilbert@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
2017-10-10libvhost-user: improve vu_queue_pop() docMarc-André Lureau
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-08libvhost-user: support resuming vq->last_avail_idx based on used_idxMarc-André Lureau
This is the same workaround as commit 523b018dde3b765, which was lost with libvhost-user transition in commit e10e798c85c2331. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-06-15vhost-user-scsi: Introduce a vhost-user-scsi sample applicationFelipe Franciosi
This commit introduces a vhost-user-scsi backend sample application. It must be linked with libiscsi and libvhost-user. To use it, compile with: $ make vhost-user-scsi And run as follows: $ ./vhost-user-scsi -u vus.sock -i iscsi://uri_to_target/ $ qemu-system-x86_64 --enable-kvm -m 512 \ -object memory-backend-file,id=mem,size=512m,share=on,mem-path=guestmem \ -numa node,memdev=mem \ -chardev socket,id=vhost-user-scsi,path=vus.sock \ -device vhost-user-scsi-pci,chardev=vhost-user-scsi \ The application is currently limited at one LUN only and it processes requests synchronously (therefore only achieving QD1). The purpose of the code is to show how a backend can be implemented and to test the vhost-user-scsi Qemu implementation. If a different instance of this vhost-user-scsi application is executed at a remote host, a VM can be live migrated to such a host. Signed-off-by: Felipe Franciosi <felipe@nutanix.com> Message-Id: <1488479153-21203-5-git-send-email-felipe@nutanix.com>
2017-05-10libvhost-user: fix crash when rings aren't readyMarc-André Lureau
Calling libvhost-user functions like vu_queue_get_avail_bytes() when the queue doesn't yet have addresses will result in the crashes like the following: Program received signal SIGSEGV, Segmentation fault. 0x000055c414112ce4 in vring_avail_idx (vq=0x55c41582fd68, vq=0x55c41582fd68) at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:940 940 vq->shadow_avail_idx = vq->vring.avail->idx; (gdb) p vq $1 = (VuVirtq *) 0x55c41582fd68 (gdb) p vq->vring $2 = {num = 0, desc = 0x0, avail = 0x0, used = 0x0, log_guest_addr = 0, flags = 0} at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:940 No locals. at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:960 num_heads = <optimized out> out_bytes=out_bytes@entry=0x7fffd035d7c4, max_in_bytes=max_in_bytes@entry=0, max_out_bytes=max_out_bytes@entry=0) at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:1034 Add a pre-condition checks on vring.avail before accessing it. Fix documentation and return type of vu_queue_empty() while at it. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Tested-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-12-16contrib: add libvhost-userMarc-André Lureau
Add a library to help implementing vhost-user backend (or slave). Dealing with vhost-user as an application developer isn't so easy: you have all the trouble with any protocol: validation, unix ancillary data, shared memory, eventfd, logging, and on top of that you need to deal with virtio queues, if possible efficiently. qemu test has a nice vhost-user testing application vhost-user-bridge, which implements most of vhost-user, and virtio.c which implements virtqueues manipulation. Based on these two, I tried to make a simple library, reusable for tests or development of new vhost-user scenarios. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> [Felipe: set used_idx copy on SET_VRING_ADDR and update shadow avail idx on SET_VRING_BASE] Signed-off-by: Felipe Franciosi <felipe@nutanix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>