309750fad5
Currently we allocate one vhost log per vhost device. This is sub optimal when: - Guest has several device with vhost as backend - Guest has multiqueue devices In the above cases, we can avoid the memory allocation by sharing a single vhost log among all the vhost devices. This is done through: - Introducing a new vhost_log structure with refcnt inside. - Using a global pointer to vhost_log structure that will be used. And introduce helper to get the log with expected log size and helper to - drop the refcnt to the old log. - Each vhost device still keep track of a pointer to the log that was used. With above, if no resize happens, all vhost device will share a single vhost log. During resize, a new vhost_log structure will be allocated and made for the global pointer. And each vhost devices will drop the refcnt to the old log. Tested by doing scp during migration for a 2 queues virtio-net-pci. Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
86 lines
2.5 KiB
C
86 lines
2.5 KiB
C
#ifndef VHOST_H
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#define VHOST_H
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#include "hw/hw.h"
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#include "hw/virtio/vhost-backend.h"
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#include "hw/virtio/virtio.h"
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#include "exec/memory.h"
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/* Generic structures common for any vhost based device. */
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struct vhost_virtqueue {
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int kick;
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int call;
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void *desc;
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void *avail;
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void *used;
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int num;
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unsigned long long used_phys;
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unsigned used_size;
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void *ring;
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unsigned long long ring_phys;
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unsigned ring_size;
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EventNotifier masked_notifier;
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};
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typedef unsigned long vhost_log_chunk_t;
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#define VHOST_LOG_PAGE 0x1000
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#define VHOST_LOG_BITS (8 * sizeof(vhost_log_chunk_t))
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#define VHOST_LOG_CHUNK (VHOST_LOG_PAGE * VHOST_LOG_BITS)
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#define VHOST_INVALID_FEATURE_BIT (0xff)
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struct vhost_log {
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unsigned long long size;
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int refcnt;
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vhost_log_chunk_t log[0];
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};
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struct vhost_memory;
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struct vhost_dev {
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MemoryListener memory_listener;
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struct vhost_memory *mem;
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int n_mem_sections;
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MemoryRegionSection *mem_sections;
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struct vhost_virtqueue *vqs;
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int nvqs;
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/* the first virtqueue which would be used by this vhost dev */
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int vq_index;
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unsigned long long features;
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unsigned long long acked_features;
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unsigned long long backend_features;
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bool started;
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bool log_enabled;
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unsigned long long log_size;
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Error *migration_blocker;
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bool force;
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bool memory_changed;
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hwaddr mem_changed_start_addr;
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hwaddr mem_changed_end_addr;
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const VhostOps *vhost_ops;
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void *opaque;
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struct vhost_log *log;
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};
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int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
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VhostBackendType backend_type, bool force);
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void vhost_dev_cleanup(struct vhost_dev *hdev);
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bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev);
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int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev);
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void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev);
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int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev);
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void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev);
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/* Test and clear masked event pending status.
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* Should be called after unmask to avoid losing events.
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*/
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bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n);
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/* Mask/unmask events from this vq.
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*/
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void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
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bool mask);
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unsigned vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
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unsigned features);
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void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
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unsigned features);
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#endif
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