2ce68e4cf5
it will allow for other parts of QEMU check if it's safe to map memory region during hotplug/runtime. That way hotplug path will have a chance to cancel hotplug operation instead of crashing in vhost_commit(). Signed-off-by: Igor Mammedov <imammedo@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/*
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* vhost-backend
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*
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* Copyright (c) 2013 Virtual Open Systems Sarl.
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*/
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#include "hw/virtio/vhost.h"
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#include "hw/virtio/vhost-backend.h"
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#include "qemu/error-report.h"
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#include "linux/vhost.h"
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#include <sys/ioctl.h>
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static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
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void *arg)
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{
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int fd = (uintptr_t) dev->opaque;
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assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
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return ioctl(fd, request, arg);
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}
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static int vhost_kernel_init(struct vhost_dev *dev, void *opaque)
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{
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assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
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dev->opaque = opaque;
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return 0;
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}
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static int vhost_kernel_cleanup(struct vhost_dev *dev)
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{
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int fd = (uintptr_t) dev->opaque;
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assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
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return close(fd);
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}
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static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx)
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{
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assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
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return idx - dev->vq_index;
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}
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static int vhost_kernel_memslots_limit(struct vhost_dev *dev)
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{
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int limit = 64;
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char *s;
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if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions",
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&s, NULL, NULL)) {
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uint64_t val = g_ascii_strtoull(s, NULL, 10);
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if (!((val == G_MAXUINT64 || !val) && errno)) {
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return val;
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}
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error_report("ignoring invalid max_mem_regions value in vhost module:"
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" %s", s);
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}
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return limit;
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}
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static const VhostOps kernel_ops = {
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.backend_type = VHOST_BACKEND_TYPE_KERNEL,
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.vhost_call = vhost_kernel_call,
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.vhost_backend_init = vhost_kernel_init,
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.vhost_backend_cleanup = vhost_kernel_cleanup,
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.vhost_backend_get_vq_index = vhost_kernel_get_vq_index,
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.vhost_backend_memslots_limit = vhost_kernel_memslots_limit,
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};
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int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
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{
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int r = 0;
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switch (backend_type) {
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case VHOST_BACKEND_TYPE_KERNEL:
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dev->vhost_ops = &kernel_ops;
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break;
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case VHOST_BACKEND_TYPE_USER:
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dev->vhost_ops = &user_ops;
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break;
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default:
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error_report("Unknown vhost backend type");
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r = -1;
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}
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return r;
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}
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