Hi
On Mon, Dec 7, 2015 at 2:37 PM, Marc-André Lureau
<marcandre.lur...@gmail.com> wrote:
> 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?
Sorry, I missed the following patch.
I am not sure it's necessary to have a user-visible property,
especially if it's overwritten later. But apparently, other properties
are already forced.
looks good overall to me, but maintainers might have different opinions.
>>
>> 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
--
Marc-André Lureau
