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Re: [Qemu-devel] [PATCH v2 1/1] vhost-user interrupt management fixes
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From: |
Michael S. Tsirkin |
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Subject: |
Re: [Qemu-devel] [PATCH v2 1/1] vhost-user interrupt management fixes |
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Date: |
Tue, 16 Feb 2016 15:58:58 +0200 |
On Tue, Feb 16, 2016 at 03:28:06PM +0200, Victor Kaplansky wrote:
> From: Didier Pallard <address@hidden>
>
> Since guest_mask_notifier can not be used in vhost-user mode due
> to buffering implied by unix control socket, force
> use_mask_notifier on virtio devices of vhost-user interfaces, and
> send correct callfd to the guest at vhost start.
>
> Using guest_notifier_mask function in vhost-user case may
> break interrupt mask paradigm, because mask/unmask is not
> really done when returning from guest_notifier_mask call, instead
> message is posted in a unix socket, and processed later.
>
> Add an option boolean flag 'use_mask_notifier' to disable the use
> of guest_notifier_mask in virtio pci.
>
> Signed-off-by: Victor Kaplansky <address@hidden>
> ---
> include/hw/virtio/virtio.h | 1 +
> hw/net/vhost_net.c | 24 ++++++++++++++++++++++--
> hw/virtio/vhost.c | 13 +++++++++++++
> hw/virtio/virtio-pci.c | 15 +++++++++------
> hw/virtio/virtio.c | 1 +
> 5 files changed, 46 insertions(+), 8 deletions(-)
>
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 108cdb0f..3acbf999 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -90,6 +90,7 @@ struct VirtIODevice
> VMChangeStateEntry *vmstate;
> char *bus_name;
> uint8_t device_endian;
> + bool use_mask_notifier;
> QLIST_HEAD(, VirtQueue) *vector_queues;
> };
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 3940a04b..22ba5571 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -17,6 +17,7 @@
> #include "net/net.h"
> #include "net/tap.h"
> #include "net/vhost-user.h"
> +#include "hw/virtio/virtio-pci.h"
>
> #include "hw/virtio/virtio-net.h"
> #include "net/vhost_net.h"
We definitely don't want a dependency on virtio-pci.
> @@ -306,13 +307,32 @@ int vhost_net_start(VirtIODevice *dev, NetClientState
> *ncs,
> }
>
> for (j = 0; j < total_queues; j++) {
> + struct vhost_net *net;
> +
> r = vhost_net_set_vnet_endian(dev, ncs[j].peer, true);
> if (r < 0) {
> goto err_endian;
> }
> - vhost_net_set_vq_index(get_vhost_net(ncs[j].peer), j * 2);
> - }
>
> + net = get_vhost_net(ncs[j].peer);
> + vhost_net_set_vq_index(net, j * 2);
> +
> + /* Force use_mask_notifier reset in vhost user case
> + * Must be done before set_guest_notifier call
> + */
> + if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER) {
Please don't do this. Add some query from vhost and do the
right thing per backend.
> + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(dev)));
> + DeviceState *d = DEVICE(qbus->parent);
> + if (!strcmp(object_get_typename(OBJECT(d)),
> TYPE_VIRTIO_NET_PCI)) {
Again, PCI dependency.
> + VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
And again here.
> + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +
> + /* Force virtual device not use mask notifier */
> + vdev->use_mask_notifier = false;
> + }
> + }
> + }
> +
> r = k->set_guest_notifiers(qbus->parent, total_queues * 2, true);
> if (r < 0) {
> error_report("Error binding guest notifier: %d", -r);
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 7dff7554..80744386 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -855,8 +855,21 @@ static int vhost_virtqueue_start(struct vhost_dev *dev,
> /* Clear and discard previous events if any. */
> event_notifier_test_and_clear(&vq->masked_notifier);
>
> + /* If vhost user, register now the call eventfd, guest_notifier_mask
> + * function is not used anymore
> + */
Can't this look at use_mask_notifier then?
> + if (dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER) {
> + file.fd =
> event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
> + r = dev->vhost_ops->vhost_set_vring_call(dev, &file);
> + if (r) {
> + r = -errno;
> + goto fail_call;
> + }
> + }
> +
> return 0;
>
> +fail_call:
> fail_kick:
> fail_alloc:
> cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev,
> idx),
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 5494ff4a..70f64cf7 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -806,7 +806,7 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy
> *proxy, int nvqs)
> /* If guest supports masking, set up irqfd now.
> * Otherwise, delay until unmasked in the frontend.
> */
> - if (k->guest_notifier_mask) {
> + if (vdev->use_mask_notifier && k->guest_notifier_mask) {
> ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);
> if (ret < 0) {
> kvm_virtio_pci_vq_vector_release(proxy, vector);
Would be cleaner to move guest_notifier_mask out from class
so we don't have to check two things.
But not a must.
> @@ -822,7 +822,7 @@ undo:
> if (vector >= msix_nr_vectors_allocated(dev)) {
> continue;
> }
> - if (k->guest_notifier_mask) {
> + if (vdev->use_mask_notifier && k->guest_notifier_mask) {
> kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> }
> kvm_virtio_pci_vq_vector_release(proxy, vector);
> @@ -849,7 +849,7 @@ static void kvm_virtio_pci_vector_release(VirtIOPCIProxy
> *proxy, int nvqs)
> /* If guest supports masking, clean up irqfd now.
> * Otherwise, it was cleaned when masked in the frontend.
> */
> - if (k->guest_notifier_mask) {
> + if (vdev->use_mask_notifier && k->guest_notifier_mask) {
> kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> }
> kvm_virtio_pci_vq_vector_release(proxy, vector);
> @@ -882,7 +882,7 @@ static int virtio_pci_vq_vector_unmask(VirtIOPCIProxy
> *proxy,
> /* If guest supports masking, irqfd is already setup, unmask it.
> * Otherwise, set it up now.
> */
> - if (k->guest_notifier_mask) {
> + if (vdev->use_mask_notifier && k->guest_notifier_mask) {
> k->guest_notifier_mask(vdev, queue_no, false);
> /* Test after unmasking to avoid losing events. */
> if (k->guest_notifier_pending &&
> @@ -905,7 +905,7 @@ static void virtio_pci_vq_vector_mask(VirtIOPCIProxy
> *proxy,
> /* If guest supports masking, keep irqfd but mask it.
> * Otherwise, clean it up now.
> */
> - if (k->guest_notifier_mask) {
> + if (vdev->use_mask_notifier && k->guest_notifier_mask) {
> k->guest_notifier_mask(vdev, queue_no, true);
> } else {
> kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> @@ -1022,7 +1022,9 @@ static int virtio_pci_set_guest_notifier(DeviceState
> *d, int n, bool assign,
> event_notifier_cleanup(notifier);
> }
>
> - if (!msix_enabled(&proxy->pci_dev) && vdc->guest_notifier_mask) {
> + if (!msix_enabled(&proxy->pci_dev) &&
> + vdev->use_mask_notifier &&
> + vdc->guest_notifier_mask) {
> vdc->guest_notifier_mask(vdev, n, !assign);
> }
>
> @@ -1879,6 +1881,7 @@ static Property virtio_pci_properties[] = {
> VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT, false),
> DEFINE_PROP_BIT("x-disable-pcie", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT, false),
> +
> DEFINE_PROP_END_OF_LIST(),
> };
>
drop this one pls.
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 90f25451..c0238b39 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -792,6 +792,7 @@ void virtio_reset(void *opaque)
> vdev->queue_sel = 0;
> vdev->status = 0;
> vdev->isr = 0;
> + vdev->use_mask_notifier = true;
> vdev->config_vector = VIRTIO_NO_VECTOR;
> virtio_notify_vector(vdev, vdev->config_vector);
>
> --
> Victor