Hi
On Thu, Dec 3, 2015 at 10:53 AM, Didier Pallard
<didier.pall...@6wind.com> wrote:
> 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 bit to disable the use of guest_notifier_mask
> in virtio pci.
Why not disabling it whenever vhost-user is used if it's broken and
inefficient to be fixed?
>
> Signed-off-by: Didier Pallard <didier.pall...@6wind.com>
> Reviewed-by: Thibaut Collet <thibaut.col...@6wind.com>
> ---
> hw/virtio/virtio-pci.c | 29 +++++++++++++++++++++++------
> hw/virtio/virtio-pci.h | 6 ++++++
> 2 files changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index dd48562..26bb617 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -806,7 +806,8 @@ 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 ((proxy->flags & VIRTIO_PCI_FLAG_USE_NOTIFIERMASK) &&
> + 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);
> @@ -822,7 +823,8 @@ undo:
> if (vector >= msix_nr_vectors_allocated(dev)) {
> continue;
> }
> - if (k->guest_notifier_mask) {
> + if ((proxy->flags & VIRTIO_PCI_FLAG_USE_NOTIFIERMASK) &&
> + k->guest_notifier_mask) {
> kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> }
> kvm_virtio_pci_vq_vector_release(proxy, vector);
> @@ -849,7 +851,8 @@ 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 ((proxy->flags & VIRTIO_PCI_FLAG_USE_NOTIFIERMASK) &&
> + k->guest_notifier_mask) {
> kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> }
> kvm_virtio_pci_vq_vector_release(proxy, vector);
> @@ -882,7 +885,8 @@ 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 ((proxy->flags & VIRTIO_PCI_FLAG_USE_NOTIFIERMASK) &&
> + 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 +909,8 @@ 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 ((proxy->flags & VIRTIO_PCI_FLAG_USE_NOTIFIERMASK) &&
> + k->guest_notifier_mask) {
> k->guest_notifier_mask(vdev, queue_no, true);
> } else {
> kvm_virtio_pci_irqfd_release(proxy, queue_no, vector);
> @@ -1022,7 +1027,9 @@ 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) &&
> + (proxy->flags & VIRTIO_PCI_FLAG_USE_NOTIFIERMASK) &&
> + vdc->guest_notifier_mask) {
> vdc->guest_notifier_mask(vdev, n, !assign);
> }
>
> @@ -1164,6 +1171,8 @@ static void virtio_9p_pci_realize(VirtIOPCIProxy
> *vpci_dev, Error **errp)
> static Property virtio_9p_pci_properties[] = {
> DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
> + DEFINE_PROP_BIT("usenotifiermask", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT, true),
> DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
> DEFINE_PROP_END_OF_LIST(),
> };
> @@ -1908,6 +1917,8 @@ static Property virtio_blk_pci_properties[] = {
> DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
> DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
> + DEFINE_PROP_BIT("usenotifiermask", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT, true),
> DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
> DEFINE_PROP_END_OF_LIST(),
> };
> @@ -1961,6 +1972,8 @@ static const TypeInfo virtio_blk_pci_info = {
> static Property virtio_scsi_pci_properties[] = {
> DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
> + DEFINE_PROP_BIT("usenotifiermask", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT, true),
> DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
> DEV_NVECTORS_UNSPECIFIED),
> DEFINE_PROP_END_OF_LIST(),
> @@ -2175,6 +2188,8 @@ static void virtio_serial_pci_realize(VirtIOPCIProxy
> *vpci_dev, Error **errp)
> static Property virtio_serial_pci_properties[] = {
> DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
> + DEFINE_PROP_BIT("usenotifiermask", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT, true),
> DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
> DEFINE_PROP_UINT32("class", VirtIOPCIProxy, class_code, 0),
> DEFINE_PROP_END_OF_LIST(),
> @@ -2215,6 +2230,8 @@ static const TypeInfo virtio_serial_pci_info = {
> static Property virtio_net_properties[] = {
> DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, false),
> + DEFINE_PROP_BIT("usenotifiermask", VirtIOPCIProxy, flags,
> + VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT, true),
> DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 3),
> DEFINE_PROP_END_OF_LIST(),
> };
> diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> index ffb74bb..aecd4eb 100644
> --- a/hw/virtio/virtio-pci.h
> +++ b/hw/virtio/virtio-pci.h
> @@ -86,6 +86,12 @@ typedef struct VirtioBusClass VirtioPCIBusClass;
> #define VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY \
> (1 << VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT)
>
> +/* Where vhost-user implementation exists, using the guest notifier mask
> + * feature can lead to improper interrupt management. Add a flag to
> + * allow to disable this guest notifier mask if desired */
> +#define VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT 6
> +#define VIRTIO_PCI_FLAG_USE_NOTIFIERMASK (1 <<
> VIRTIO_PCI_FLAG_USE_NOTIFIERMASK_BIT)
> +
> typedef struct {
> MSIMessage msg;
> int virq;
> --
> 2.1.4
>
>
--
Marc-André Lureau
