From: "Marc-André Lureau" <marcandre.lureau@gmail.com>
To: Didier Pallard <didier.pallard@6wind.com>
Cc: Thibaut Collet <thibaut.collet@6wind.com>,
Jean-Mickael Guerin <jmg@6wind.com>, QEMU <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH 2/3] virtio-pci: add an option to bypass guest_notifier_mask
Date: Mon, 7 Dec 2015 14:59:10 +0100 [thread overview]
Message-ID: <CAJ+F1CKAkYGzPnt+eha+s6e=++3914a4J=bLWsUDxShO+NqnLQ@mail.gmail.com> (raw)
In-Reply-To: <CAJ+F1CJx06qx0FbXHywKx6aCKMU5rcUpi10Ato2sM=-fC=xZkw@mail.gmail.com>
Hi
On Mon, Dec 7, 2015 at 2:37 PM, Marc-André Lureau
<marcandre.lureau@gmail.com> wrote:
> Hi
>
> On Thu, Dec 3, 2015 at 10:53 AM, Didier Pallard
> <didier.pallard@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.pallard@6wind.com>
>> Reviewed-by: Thibaut Collet <thibaut.collet@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
next prev parent reply other threads:[~2015-12-07 13:59 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-03 9:53 [Qemu-devel] Linux vhost-user interrupt management fixes Didier Pallard
2015-12-03 9:53 ` [Qemu-devel] [PATCH 1/3] char: fix vhost-user socket full Didier Pallard
2015-12-07 13:31 ` Marc-André Lureau
2015-12-09 15:59 ` Victor Kaplansky
2015-12-09 17:06 ` Didier Pallard
2015-12-10 12:56 ` Victor Kaplansky
2015-12-10 15:09 ` Didier Pallard
2015-12-17 14:41 ` Victor Kaplansky
2016-02-04 13:13 ` Michael S. Tsirkin
2016-02-04 14:10 ` Michael S. Tsirkin
2016-02-08 13:12 ` Didier Pallard
2016-02-09 11:37 ` Michael S. Tsirkin
2016-02-09 11:48 ` Daniel P. Berrange
2016-02-09 12:21 ` Michael S. Tsirkin
2016-02-09 16:17 ` Didier Pallard
2016-02-09 16:50 ` Michael S. Tsirkin
2016-02-09 17:04 ` Daniel P. Berrange
2016-02-10 9:35 ` Didier Pallard
2016-02-10 11:53 ` Michael S. Tsirkin
2016-02-10 12:15 ` Daniel P. Berrange
2016-02-19 9:09 ` Didier Pallard
2015-12-03 9:53 ` [Qemu-devel] [PATCH 2/3] virtio-pci: add an option to bypass guest_notifier_mask Didier Pallard
2015-12-07 13:37 ` Marc-André Lureau
2015-12-07 13:59 ` Marc-André Lureau [this message]
2015-12-09 15:06 ` Didier Pallard
2016-02-04 13:08 ` Michael S. Tsirkin
2016-02-08 13:24 ` Didier Pallard
2016-02-15 15:38 ` Victor Kaplansky
2015-12-03 9:53 ` [Qemu-devel] [PATCH 3/3] vhost-net: force guest_notifier_mask bypass in vhost-user case Didier Pallard
2016-02-04 13:06 ` Michael S. Tsirkin
2015-12-04 10:04 ` [Qemu-devel] Linux vhost-user interrupt management fixes Didier Pallard
2016-01-25 9:22 ` Victor Kaplansky
2016-01-26 9:25 ` Didier Pallard
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