search for: virtqueue_notifi

Replace virtqueue_kick by virtqueue_kick_prepare, which requires serialization, and virtqueue_notify, which does not. Repurpose the return values to indicate whether the vq should be notified. This fixes a lock contention with qemu host. When the guest calls vibad rtqueue_notify, the qemu vcpu thread exits the guest and waits for the qemu iothread to perform the MMIO. If the qemu iothread is

Replace virtqueue_kick by virtqueue_kick_prepare, which requires serialization, and virtqueue_notify, which does not. Repurpose the return values to indicate whether the vq should be notified. This fixes a lock contention with qemu host. When the guest calls vibad rtqueue_notify, the qemu vcpu thread exits the guest and waits for the qemu iothread to perform the MMIO. If the qemu iothread is

Deleting the disk and partitions in virtblk_remove() via del_gendisk() causes never ending waits when trying to synch dirty inode pages. A dummy virtqueue_notify() in virtblk_remove() is used to detect a host notification error, latter occurs when block device was hot-unplugged. When the dummy host kick failed blk_cleanup_queue() should be invoked prior to del_gendisk(). Signed-off-by: Heinz

Based on patch by Christoph for virtio_blk speedup: Split virtqueue_kick to be able to do the actual notification outside the lock protecting the virtqueue. This patch was originally done by Stefan Hajnoczi, but I can't find the original one anymore and had to recreated it from memory. Pointers to the original or corrections for the commit message are welcome. Signed-off-by: Rusty

Based on patch by Christoph for virtio_blk speedup: Split virtqueue_kick to be able to do the actual notification outside the lock protecting the virtqueue. This patch was originally done by Stefan Hajnoczi, but I can't find the original one anymore and had to recreated it from memory. Pointers to the original or corrections for the commit message are welcome. Signed-off-by: Rusty

Replace virtqueue_kick by virtqueue_kick_prepare, which requires serialization, and virtqueue_notify, which does not. Repurpose the return values to indicate whether the vq should be notified. This fixes a bad spinlock contention when the host is qemu. When the guest calls virtqueue_notify, the qemu vcpu thread exits the guest and waits for the qemu iothread to perform the MMIO. If the qemu

Split virtqueue_kick() call into virtqueue_kick_prepare(), which requires serialization, and virtqueue_notify(), which does not. Move the virtqueue_notify() call out of the critical section protected by the queue lock. This avoids triggering a vmexit while holding the lock and thereby fixes a rather bad spinlock contention. Suggested-by: Chia-I Wu <olvaffe at gmail.com> Signed-off-by:

Firstly, it isn't necessary to hold lock of vblk->vq_lock when notifying hypervisor about queued I/O. Secondly, virtqueue_notify() will cause world switch and it may take long time on some hypervisors(such as, qemu-arm), so it isn't good to hold the lock and block other vCPUs. On arm64 quad core VM(qemu-kvm), the patch can increase I/O performance a lot with VIRTIO_RING_F_EVENT_IDX

Firstly, it isn't necessary to hold lock of vblk->vq_lock when notifying hypervisor about queued I/O. Secondly, virtqueue_notify() will cause world switch and it may take long time on some hypervisors(such as, qemu-arm), so it isn't good to hold the lock and block other vCPUs. On arm64 quad core VM(qemu-kvm), the patch can increase I/O performance a lot with VIRTIO_RING_F_EVENT_IDX

Hi, this patch-set tries to solve various hang situations when virtio devices (network or block) are hot-unplugged from a KVM guest. On System z there exists no handshake mechanism between host and guest when a device is hot-unplugged. The device is removed and no further I/O is possible. The guest is notified about the hard removal with a CRW machine check. As per architecture, the host must

Hi, this patch-set tries to solve various hang situations when virtio devices (network or block) are hot-unplugged from a KVM guest. On System z there exists no handshake mechanism between host and guest when a device is hot-unplugged. The device is removed and no further I/O is possible. The guest is notified about the hard removal with a CRW machine check. As per architecture, the host must

When the driver submits multiple commands in a row it makes sense to notify the host only after submitting the last one, so the host can process them all at once, with a single vmexit. Add functions to enable/disable notifications to allow that. Use the new functions for primary plane updates. Signed-off-by: Gerd Hoffmann <kraxel at redhat.com> --- drivers/gpu/drm/virtio/virtgpu_drv.h

When the driver submits multiple commands in a row it makes sense to notify the host only after submitting the last one, so the host can process them all at once, with a single vmexit. Add functions to enable/disable notifications to allow that. Use the new functions for primary plane updates. Signed-off-by: Gerd Hoffmann <kraxel at redhat.com> --- drivers/gpu/drm/virtio/virtgpu_drv.h

Hi, this patch-set solves a hang situation when a vlan network device is hot-unplugged from a KVM guest. On System z there exists no handshake mechanism between host and guest when a device is hot-unplugged. The device is removed and no further I/O is possible. The guest is notified about the hard removal with a CRW machine check. As per architecture, the host must repond to any I/O operation

Hi, this patch-set solves a hang situation when a vlan network device is hot-unplugged from a KVM guest. On System z there exists no handshake mechanism between host and guest when a device is hot-unplugged. The device is removed and no further I/O is possible. The guest is notified about the hard removal with a CRW machine check. As per architecture, the host must repond to any I/O operation

Drop the virtio_gpu_{disable,enable}_notify(). Add a new virtio_gpu_notify() call instead, which must be called whenever the driver wants make sure the host is notified needed. Drop notification from command submission. Add virtio_gpu_notify() calls everywhere instead. This results in more batching because we now notify only once for a series of commands. We already had that for page flips,

Drop the virtio_gpu_{disable,enable}_notify(). Add a new virtio_gpu_notify() call instead, which must be called whenever the driver wants make sure the host is notified needed. Drop notification from command submission. Add virtio_gpu_notify() calls everywhere instead. This results in more batching because we now notify only once for a series of commands. We already had that for page flips,

Currently we are duplicating logic to send forgets at two places. Consolidate the code by calling one helper function. This also uses virtqueue_add_outbuf() instead of virtqueue_add_sgs(). Former is simpler to call. Signed-off-by: Vivek Goyal <vgoyal at redhat.com> --- fs/fuse/virtio_fs.c | 150 +++++++++++++++++++------------------------- 1 file changed, 63 insertions(+), 87 deletions(-)

virtio spec requires that all drivers set DRIVER_OK before using devices. While rpmsg isn't yet included in the virtio 1 spec, previous spec versions also required this. virtio rpmsg violates this rule: is calls kick before setting DRIVER_OK. The fix isn't trivial since simply calling virtio_device_ready earlier would mean we might get an interrupt in parallel with adding buffers.

virtio spec requires that all drivers set DRIVER_OK before using devices. While rpmsg isn't yet included in the virtio 1 spec, previous spec versions also required this. virtio rpmsg violates this rule: is calls kick before setting DRIVER_OK. The fix isn't trivial since simply calling virtio_device_ready earlier would mean we might get an interrupt in parallel with adding buffers.