* [Qemu-devel] [PATCH 1/8] virtio: don't waste irqfds on control vqs
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2013-01-03 11:51 ` Stefan Hajnoczi
2012-12-26 10:52 ` [Qemu-devel] [PATCH 2/8] msix: add api to access msix message Michael S. Tsirkin
` (6 subsequent siblings)
7 siblings, 1 reply; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
Pass nvqs to set_guest_notifiers. This makes it possible to
save on irqfds by not allocating one for the control vq
for virtio-net.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/vhost.c | 10 +++++++---
hw/virtio-pci.c | 19 ++++++++++++++-----
hw/virtio-pci.h | 1 +
hw/virtio.h | 2 +-
4 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/hw/vhost.c b/hw/vhost.c
index 4e1cb47..b6d73ca 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -879,7 +879,9 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
goto fail;
}
- r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, true);
+ r = vdev->binding->set_guest_notifiers(vdev->binding_opaque,
+ hdev->nvqs,
+ true);
if (r < 0) {
fprintf(stderr, "Error binding guest notifier: %d\n", -r);
goto fail_notifiers;
@@ -929,7 +931,7 @@ fail_vq:
}
fail_mem:
fail_features:
- vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
+ vdev->binding->set_guest_notifiers(vdev->binding_opaque, hdev->nvqs, false);
fail_notifiers:
fail:
return r;
@@ -950,7 +952,9 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
vhost_sync_dirty_bitmap(hdev, &hdev->mem_sections[i],
0, (hwaddr)~0x0ull);
}
- r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
+ r = vdev->binding->set_guest_notifiers(vdev->binding_opaque,
+ hdev->nvqs,
+ false);
if (r < 0) {
fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);
fflush(stderr);
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index af9a56c..3c258a4 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -535,7 +535,7 @@ static int kvm_virtio_pci_vector_use(PCIDevice *dev, unsigned vector,
VirtIODevice *vdev = proxy->vdev;
int ret, queue_no;
- for (queue_no = 0; queue_no < VIRTIO_PCI_QUEUE_MAX; queue_no++) {
+ for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
if (!virtio_queue_get_num(vdev, queue_no)) {
break;
}
@@ -565,7 +565,7 @@ static void kvm_virtio_pci_vector_release(PCIDevice *dev, unsigned vector)
VirtIODevice *vdev = proxy->vdev;
int queue_no;
- for (queue_no = 0; queue_no < VIRTIO_PCI_QUEUE_MAX; queue_no++) {
+ for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
if (!virtio_queue_get_num(vdev, queue_no)) {
break;
}
@@ -587,7 +587,7 @@ static void kvm_virtio_pci_vector_poll(PCIDevice *dev,
EventNotifier *notifier;
VirtQueue *vq;
- for (queue_no = 0; queue_no < VIRTIO_PCI_QUEUE_MAX; queue_no++) {
+ for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
if (!virtio_queue_get_num(vdev, queue_no)) {
break;
}
@@ -631,7 +631,7 @@ static bool virtio_pci_query_guest_notifiers(DeviceState *d)
return msix_enabled(&proxy->pci_dev);
}
-static int virtio_pci_set_guest_notifiers(DeviceState *d, bool assign)
+static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
{
VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
VirtIODevice *vdev = proxy->vdev;
@@ -639,6 +639,15 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, bool assign)
bool with_irqfd = msix_enabled(&proxy->pci_dev) &&
kvm_msi_via_irqfd_enabled();
+ nvqs = MIN(nvqs, VIRTIO_PCI_QUEUE_MAX);
+
+ /* When deassigning, pass a consistent nvqs value
+ * to avoid leaking notifiers.
+ */
+ assert(assign || nvqs == proxy->nvqs_with_notifiers);
+
+ proxy->nvqs_with_notifiers = nvqs;
+
/* Must unset vector notifier while guest notifier is still assigned */
if (proxy->vector_irqfd && !assign) {
msix_unset_vector_notifiers(&proxy->pci_dev);
@@ -646,7 +655,7 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, bool assign)
proxy->vector_irqfd = NULL;
}
- for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {
+ for (n = 0; n < nvqs; n++) {
if (!virtio_queue_get_num(vdev, n)) {
break;
}
diff --git a/hw/virtio-pci.h b/hw/virtio-pci.h
index b58d9a2..b0f17e2 100644
--- a/hw/virtio-pci.h
+++ b/hw/virtio-pci.h
@@ -51,6 +51,7 @@ typedef struct {
bool ioeventfd_disabled;
bool ioeventfd_started;
VirtIOIRQFD *vector_irqfd;
+ int nvqs_with_notifiers;
} VirtIOPCIProxy;
void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev);
diff --git a/hw/virtio.h b/hw/virtio.h
index 1dec9dc..329b426 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -99,7 +99,7 @@ typedef struct {
int (*load_done)(DeviceState *d, QEMUFile *f);
unsigned (*get_features)(DeviceState *d);
bool (*query_guest_notifiers)(DeviceState *d);
- int (*set_guest_notifiers)(DeviceState *d, bool assigned);
+ int (*set_guest_notifiers)(DeviceState *d, int nvqs, bool assigned);
int (*set_host_notifier)(DeviceState *d, int n, bool assigned);
void (*vmstate_change)(DeviceState *d, bool running);
} VirtIOBindings;
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [Qemu-devel] [PATCH 1/8] virtio: don't waste irqfds on control vqs
2012-12-26 10:52 ` [Qemu-devel] [PATCH 1/8] virtio: don't waste irqfds on control vqs Michael S. Tsirkin
@ 2013-01-03 11:51 ` Stefan Hajnoczi
0 siblings, 0 replies; 10+ messages in thread
From: Stefan Hajnoczi @ 2013-01-03 11:51 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: asias, qemu-devel
On Wed, Dec 26, 2012 at 12:52:19PM +0200, Michael S. Tsirkin wrote:
> Pass nvqs to set_guest_notifiers. This makes it possible to
> save on irqfds by not allocating one for the control vq
> for virtio-net.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> hw/vhost.c | 10 +++++++---
> hw/virtio-pci.c | 19 ++++++++++++++-----
> hw/virtio-pci.h | 1 +
> hw/virtio.h | 2 +-
> 4 files changed, 23 insertions(+), 9 deletions(-)
Good idea!
This patch assumes only the first n virtqueues need irqfd. Depending on
the device's virtqueue ordering this may not work (e.g. control vq first
followed by data vqs). But this is a theoretical point, let's wait
until we hit it and need something fancier.
Stefan
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Qemu-devel] [PATCH 2/8] msix: add api to access msix message
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 1/8] virtio: don't waste irqfds on control vqs Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 4/8] virtio-pci: cache msix messages Michael S. Tsirkin
` (5 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
Will be used by virtio pci.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/pci/msix.c | 2 +-
hw/pci/msix.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 9eee657..e231a0d 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -27,7 +27,7 @@
#define MSIX_ENABLE_MASK (PCI_MSIX_FLAGS_ENABLE >> 8)
#define MSIX_MASKALL_MASK (PCI_MSIX_FLAGS_MASKALL >> 8)
-static MSIMessage msix_get_message(PCIDevice *dev, unsigned vector)
+MSIMessage msix_get_message(PCIDevice *dev, unsigned vector)
{
uint8_t *table_entry = dev->msix_table + vector * PCI_MSIX_ENTRY_SIZE;
MSIMessage msg;
diff --git a/hw/pci/msix.h b/hw/pci/msix.h
index d0c4429..e648410 100644
--- a/hw/pci/msix.h
+++ b/hw/pci/msix.h
@@ -5,6 +5,7 @@
#include "hw/pci/pci.h"
void msix_set_message(PCIDevice *dev, int vector, MSIMessage msg);
+MSIMessage msix_get_message(PCIDevice *dev, unsigned int vector);
int msix_init(PCIDevice *dev, unsigned short nentries,
MemoryRegion *table_bar, uint8_t table_bar_nr,
unsigned table_offset, MemoryRegion *pba_bar,
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* [Qemu-devel] [PATCH 4/8] virtio-pci: cache msix messages
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 1/8] virtio: don't waste irqfds on control vqs Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 2/8] msix: add api to access msix message Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 3/8] kvm: add stub for update msi route Michael S. Tsirkin
` (4 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
Some guests mask a vector then unmask without changing it.
Store vectors to avoid kvm system calls in this case.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/virtio-pci.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++----------
hw/virtio-pci.h | 1 +
2 files changed, 100 insertions(+), 20 deletions(-)
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 3c258a4..1d77146 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -487,8 +487,6 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
unsigned int vector,
MSIMessage msg)
{
- VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
- EventNotifier *n = virtio_queue_get_guest_notifier(vq);
VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
int ret;
@@ -500,18 +498,94 @@ static int kvm_virtio_pci_vq_vector_use(VirtIOPCIProxy *proxy,
irqfd->virq = ret;
}
irqfd->users++;
+ return 0;
+}
- ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq);
- if (ret < 0) {
- if (--irqfd->users == 0) {
- kvm_irqchip_release_virq(kvm_state, irqfd->virq);
+static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,
+ unsigned int vector)
+{
+ VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+ if (--irqfd->users == 0) {
+ kvm_irqchip_release_virq(kvm_state, irqfd->virq);
+ }
+}
+
+static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
+{
+ PCIDevice *dev = &proxy->pci_dev;
+ VirtIODevice *vdev = proxy->vdev;
+ unsigned int vector;
+ int ret, queue_no;
+ MSIMessage msg;
+
+ for (queue_no = 0; queue_no < nvqs; queue_no++) {
+ if (!virtio_queue_get_num(vdev, queue_no)) {
+ break;
+ }
+ vector = virtio_queue_vector(vdev, queue_no);
+ if (vector >= msix_nr_vectors_allocated(dev)) {
+ continue;
+ }
+ msg = msix_get_message(dev, vector);
+ ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector, msg);
+ if (ret < 0) {
+ goto undo;
}
- return ret;
}
return 0;
+
+undo:
+ while (--queue_no >= 0) {
+ vector = virtio_queue_vector(vdev, queue_no);
+ if (vector >= msix_nr_vectors_allocated(dev)) {
+ continue;
+ }
+ kvm_virtio_pci_vq_vector_release(proxy, vector);
+ }
+ return ret;
}
-static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,
+static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
+{
+ PCIDevice *dev = &proxy->pci_dev;
+ VirtIODevice *vdev = proxy->vdev;
+ unsigned int vector;
+ int queue_no;
+
+ for (queue_no = 0; queue_no < nvqs; queue_no++) {
+ if (!virtio_queue_get_num(vdev, queue_no)) {
+ break;
+ }
+ vector = virtio_queue_vector(vdev, queue_no);
+ if (vector >= msix_nr_vectors_allocated(dev)) {
+ continue;
+ }
+ kvm_virtio_pci_vq_vector_release(proxy, vector);
+ }
+}
+
+static int kvm_virtio_pci_vq_vector_unmask(VirtIOPCIProxy *proxy,
+ unsigned int queue_no,
+ unsigned int vector,
+ MSIMessage msg)
+{
+ VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
+ EventNotifier *n = virtio_queue_get_guest_notifier(vq);
+ VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+ int ret;
+
+ if (irqfd->msg.data != msg.data || irqfd->msg.address != msg.address) {
+ ret = kvm_irqchip_update_msi_route(kvm_state, irqfd->virq, msg);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+
+ ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq);
+ return ret;
+}
+
+static void kvm_virtio_pci_vq_vector_mask(VirtIOPCIProxy *proxy,
unsigned int queue_no,
unsigned int vector)
{
@@ -522,13 +596,9 @@ static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,
ret = kvm_irqchip_remove_irqfd_notifier(kvm_state, n, irqfd->virq);
assert(ret == 0);
-
- if (--irqfd->users == 0) {
- kvm_irqchip_release_virq(kvm_state, irqfd->virq);
- }
}
-static int kvm_virtio_pci_vector_use(PCIDevice *dev, unsigned vector,
+static int kvm_virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector,
MSIMessage msg)
{
VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev);
@@ -542,7 +612,7 @@ static int kvm_virtio_pci_vector_use(PCIDevice *dev, unsigned vector,
if (virtio_queue_vector(vdev, queue_no) != vector) {
continue;
}
- ret = kvm_virtio_pci_vq_vector_use(proxy, queue_no, vector, msg);
+ ret = kvm_virtio_pci_vq_vector_unmask(proxy, queue_no, vector, msg);
if (ret < 0) {
goto undo;
}
@@ -554,12 +624,12 @@ undo:
if (virtio_queue_vector(vdev, queue_no) != vector) {
continue;
}
- kvm_virtio_pci_vq_vector_release(proxy, queue_no, vector);
+ kvm_virtio_pci_vq_vector_mask(proxy, queue_no, vector);
}
return ret;
}
-static void kvm_virtio_pci_vector_release(PCIDevice *dev, unsigned vector)
+static void kvm_virtio_pci_vector_mask(PCIDevice *dev, unsigned vector)
{
VirtIOPCIProxy *proxy = container_of(dev, VirtIOPCIProxy, pci_dev);
VirtIODevice *vdev = proxy->vdev;
@@ -572,7 +642,7 @@ static void kvm_virtio_pci_vector_release(PCIDevice *dev, unsigned vector)
if (virtio_queue_vector(vdev, queue_no) != vector) {
continue;
}
- kvm_virtio_pci_vq_vector_release(proxy, queue_no, vector);
+ kvm_virtio_pci_vq_vector_mask(proxy, queue_no, vector);
}
}
@@ -651,6 +721,7 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
/* Must unset vector notifier while guest notifier is still assigned */
if (proxy->vector_irqfd && !assign) {
msix_unset_vector_notifiers(&proxy->pci_dev);
+ kvm_virtio_pci_vector_release(proxy, nvqs);
g_free(proxy->vector_irqfd);
proxy->vector_irqfd = NULL;
}
@@ -672,17 +743,25 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
proxy->vector_irqfd =
g_malloc0(sizeof(*proxy->vector_irqfd) *
msix_nr_vectors_allocated(&proxy->pci_dev));
+ r = kvm_virtio_pci_vector_use(proxy, nvqs);
+ if (r < 0) {
+ goto assign_error;
+ }
r = msix_set_vector_notifiers(&proxy->pci_dev,
- kvm_virtio_pci_vector_use,
- kvm_virtio_pci_vector_release,
+ kvm_virtio_pci_vector_unmask,
+ kvm_virtio_pci_vector_mask,
kvm_virtio_pci_vector_poll);
if (r < 0) {
- goto assign_error;
+ goto notifiers_error;
}
}
return 0;
+notifiers_error:
+ assert(assign);
+ kvm_virtio_pci_vector_release(proxy, nvqs);
+
assign_error:
/* We get here on assignment failure. Recover by undoing for VQs 0 .. n. */
assert(assign);
diff --git a/hw/virtio-pci.h b/hw/virtio-pci.h
index b0f17e2..9ff3139 100644
--- a/hw/virtio-pci.h
+++ b/hw/virtio-pci.h
@@ -27,6 +27,7 @@
#define VIRTIO_PCI_FLAG_USE_IOEVENTFD (1 << VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT)
typedef struct {
+ MSIMessage msg;
int virq;
unsigned int users;
} VirtIOIRQFD;
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* [Qemu-devel] [PATCH 3/8] kvm: add stub for update msi route
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
` (2 preceding siblings ...)
2012-12-26 10:52 ` [Qemu-devel] [PATCH 4/8] virtio-pci: cache msix messages Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 5/8] virtio: backend virtqueue notifier masking Michael S. Tsirkin
` (3 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
Will be used by virtio-pci.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
kvm-stub.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kvm-stub.c b/kvm-stub.c
index 5b97152..81f8967 100644
--- a/kvm-stub.c
+++ b/kvm-stub.c
@@ -131,6 +131,11 @@ void kvm_irqchip_release_virq(KVMState *s, int virq)
{
}
+int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg)
+{
+ return -ENOSYS;
+}
+
int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n, int virq)
{
return -ENOSYS;
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* [Qemu-devel] [PATCH 5/8] virtio: backend virtqueue notifier masking
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
` (3 preceding siblings ...)
2012-12-26 10:52 ` [Qemu-devel] [PATCH 3/8] kvm: add stub for update msi route Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 8/8] vhost: backend masking support Michael S. Tsirkin
` (2 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
some backends (notably vhost) can mask events
at their source in a way that is more efficient
than masking through kvm.
Specifically
- masking in kvm uses rcu write side so it has high latency
- in kvm on unmask we always send an interrupt
masking at source does not have these issues.
Add such support in virtio.h and use in virtio-pci.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/virtio-pci.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
hw/virtio.h | 13 ++++++++++
2 files changed, 83 insertions(+), 9 deletions(-)
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 1d77146..aad9d6d 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -510,6 +510,31 @@ static void kvm_virtio_pci_vq_vector_release(VirtIOPCIProxy *proxy,
}
}
+static int kvm_virtio_pci_irqfd_use(VirtIOPCIProxy *proxy,
+ unsigned int queue_no,
+ unsigned int vector)
+{
+ VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+ VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
+ EventNotifier *n = virtio_queue_get_guest_notifier(vq);
+ int ret;
+ ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq);
+ return ret;
+}
+
+static void kvm_virtio_pci_irqfd_release(VirtIOPCIProxy *proxy,
+ unsigned int queue_no,
+ unsigned int vector)
+{
+ VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
+ EventNotifier *n = virtio_queue_get_guest_notifier(vq);
+ VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
+ int ret;
+
+ ret = kvm_irqchip_remove_irqfd_notifier(kvm_state, n, irqfd->virq);
+ assert(ret == 0);
+}
+
static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
{
PCIDevice *dev = &proxy->pci_dev;
@@ -531,6 +556,16 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
if (ret < 0) {
goto undo;
}
+ /* If guest supports masking, set up irqfd now.
+ * Otherwise, delay until unmasked in the frontend.
+ */
+ if (proxy->vdev->guest_notifier_mask) {
+ ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);
+ if (ret < 0) {
+ kvm_virtio_pci_vq_vector_release(proxy, vector);
+ goto undo;
+ }
+ }
}
return 0;
@@ -540,6 +575,9 @@ undo:
if (vector >= msix_nr_vectors_allocated(dev)) {
continue;
}
+ if (proxy->vdev->guest_notifier_mask) {
+ kvm_virtio_pci_irqfd_release(proxy, vector, queue_no);
+ }
kvm_virtio_pci_vq_vector_release(proxy, vector);
}
return ret;
@@ -560,6 +598,12 @@ static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
if (vector >= msix_nr_vectors_allocated(dev)) {
continue;
}
+ /* If guest supports masking, clean up irqfd now.
+ * Otherwise, it was cleaned when masked in the frontend.
+ */
+ if (proxy->vdev->guest_notifier_mask) {
+ kvm_virtio_pci_irqfd_release(proxy, vector, queue_no);
+ }
kvm_virtio_pci_vq_vector_release(proxy, vector);
}
}
@@ -581,7 +625,19 @@ static int kvm_virtio_pci_vq_vector_unmask(VirtIOPCIProxy *proxy,
}
}
- ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq);
+ /* If guest supports masking, irqfd is already setup, unmask it.
+ * Otherwise, set it up now.
+ */
+ if (proxy->vdev->guest_notifier_mask) {
+ proxy->vdev->guest_notifier_mask(proxy->vdev, queue_no, false);
+ /* Test after unmasking to avoid losing events. */
+ if (proxy->vdev->guest_notifier_pending &&
+ proxy->vdev->guest_notifier_pending(proxy->vdev, queue_no)) {
+ event_notifier_set(n);
+ }
+ } else {
+ ret = kvm_virtio_pci_irqfd_use(proxy, queue_no, vector);
+ }
return ret;
}
@@ -589,13 +645,14 @@ static void kvm_virtio_pci_vq_vector_mask(VirtIOPCIProxy *proxy,
unsigned int queue_no,
unsigned int vector)
{
- VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
- EventNotifier *n = virtio_queue_get_guest_notifier(vq);
- VirtIOIRQFD *irqfd = &proxy->vector_irqfd[vector];
- int ret;
-
- ret = kvm_irqchip_remove_irqfd_notifier(kvm_state, n, irqfd->virq);
- assert(ret == 0);
+ /* If guest supports masking, keep irqfd but mask it.
+ * Otherwise, clean it up now.
+ */
+ if (proxy->vdev->guest_notifier_mask) {
+ proxy->vdev->guest_notifier_mask(proxy->vdev, queue_no, true);
+ } else {
+ kvm_virtio_pci_irqfd_release(proxy, vector, queue_no);
+ }
}
static int kvm_virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector,
@@ -668,7 +725,11 @@ static void kvm_virtio_pci_vector_poll(PCIDevice *dev,
}
vq = virtio_get_queue(vdev, queue_no);
notifier = virtio_queue_get_guest_notifier(vq);
- if (event_notifier_test_and_clear(notifier)) {
+ if (vdev->guest_notifier_pending) {
+ if (vdev->guest_notifier_pending(vdev, queue_no)) {
+ msix_set_pending(dev, vector);
+ }
+ } else if (event_notifier_test_and_clear(notifier)) {
msix_set_pending(dev, vector);
}
}
diff --git a/hw/virtio.h b/hw/virtio.h
index 329b426..b9f1873 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -126,6 +126,19 @@ struct VirtIODevice
void (*set_config)(VirtIODevice *vdev, const uint8_t *config);
void (*reset)(VirtIODevice *vdev);
void (*set_status)(VirtIODevice *vdev, uint8_t val);
+ /* Test and clear event pending status.
+ * Should be called after unmask to avoid losing events.
+ * If backend does not support masking,
+ * must check in frontend instead.
+ */
+ bool (*guest_notifier_pending)(VirtIODevice *vdev, int n);
+ /* Mask/unmask events from this vq. Any events reported
+ * while masked will become pending.
+ * If backend does not support masking,
+ * must mask in frontend instead.
+ */
+ void (*guest_notifier_mask)(VirtIODevice *vdev, int n, bool mask);
+
VirtQueue *vq;
const VirtIOBindings *binding;
DeviceState *binding_opaque;
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* [Qemu-devel] [PATCH 8/8] vhost: backend masking support
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
` (4 preceding siblings ...)
2012-12-26 10:52 ` [Qemu-devel] [PATCH 5/8] virtio: backend virtqueue notifier masking Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 6/8] virtio-net: set/clear vhost_started in reverse order Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 7/8] vhost: set started flag while start is in progress Michael S. Tsirkin
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
Support backend guest notifier masking in vhost-net:
create eventfd at device init, when masked,
make vhost use that as eventfd instead of
sending an interrupt.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/vhost.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++--------
hw/vhost.h | 10 ++++++
hw/vhost_net.c | 27 ++++++++++++++--
hw/vhost_net.h | 3 ++
hw/virtio-net.c | 18 +++++++++++
5 files changed, 137 insertions(+), 16 deletions(-)
diff --git a/hw/vhost.c b/hw/vhost.c
index 4fa5007..cee8aad 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -612,7 +612,7 @@ static void vhost_log_stop(MemoryListener *listener,
/* FIXME: implement */
}
-static int vhost_virtqueue_init(struct vhost_dev *dev,
+static int vhost_virtqueue_start(struct vhost_dev *dev,
struct VirtIODevice *vdev,
struct vhost_virtqueue *vq,
unsigned idx)
@@ -681,16 +681,11 @@ static int vhost_virtqueue_init(struct vhost_dev *dev,
goto fail_kick;
}
- file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
- r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
- if (r) {
- r = -errno;
- goto fail_call;
- }
+ /* Clear and discard previous events if any. */
+ event_notifier_test_and_clear(&vq->masked_notifier);
return 0;
-fail_call:
fail_kick:
fail_alloc:
cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
@@ -708,7 +703,7 @@ fail_alloc_desc:
return r;
}
-static void vhost_virtqueue_cleanup(struct vhost_dev *dev,
+static void vhost_virtqueue_stop(struct vhost_dev *dev,
struct VirtIODevice *vdev,
struct vhost_virtqueue *vq,
unsigned idx)
@@ -746,11 +741,39 @@ static void vhost_eventfd_del(MemoryListener *listener,
{
}
+static int vhost_virtqueue_init(struct vhost_dev *dev,
+ struct vhost_virtqueue *vq, int n)
+{
+ struct vhost_vring_file file = {
+ .index = n,
+ };
+ int r = event_notifier_init(&vq->masked_notifier, 0);
+ if (r < 0) {
+ return r;
+ }
+
+ file.fd = event_notifier_get_fd(&vq->masked_notifier);
+ r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
+ if (r) {
+ r = -errno;
+ goto fail_call;
+ }
+ return 0;
+fail_call:
+ event_notifier_cleanup(&vq->masked_notifier);
+ return r;
+}
+
+static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
+{
+ event_notifier_cleanup(&vq->masked_notifier);
+}
+
int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
bool force)
{
uint64_t features;
- int r;
+ int i, r;
if (devfd >= 0) {
hdev->control = devfd;
} else {
@@ -768,6 +791,13 @@ int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
if (r < 0) {
goto fail;
}
+
+ for (i = 0; i < hdev->nvqs; ++i) {
+ r = vhost_virtqueue_init(hdev, hdev->vqs + i, i);
+ if (r < 0) {
+ goto fail_vq;
+ }
+ }
hdev->features = features;
hdev->memory_listener = (MemoryListener) {
@@ -795,6 +825,10 @@ int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
memory_listener_register(&hdev->memory_listener, &address_space_memory);
hdev->force = force;
return 0;
+fail_vq:
+ while (--i >= 0) {
+ vhost_virtqueue_cleanup(hdev->vqs + i);
+ }
fail:
r = -errno;
close(hdev->control);
@@ -803,6 +837,10 @@ fail:
void vhost_dev_cleanup(struct vhost_dev *hdev)
{
+ int i;
+ for (i = 0; i < hdev->nvqs; ++i) {
+ vhost_virtqueue_cleanup(hdev->vqs + i);
+ }
memory_listener_unregister(&hdev->memory_listener);
g_free(hdev->mem);
g_free(hdev->mem_sections);
@@ -869,6 +907,37 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
}
}
+/* Test and clear event pending status.
+ * Should be called after unmask to avoid losing events.
+ */
+bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n)
+{
+ struct vhost_virtqueue *vq = hdev->vqs + n;
+ assert(hdev->started);
+ return event_notifier_test_and_clear(&vq->masked_notifier);
+}
+
+/* Mask/unmask events from this vq. */
+void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
+ bool mask)
+{
+ struct VirtQueue *vvq = virtio_get_queue(vdev, n);
+ int r;
+
+ assert(hdev->started);
+
+ struct vhost_vring_file file = {
+ .index = n,
+ };
+ if (mask) {
+ file.fd = event_notifier_get_fd(&hdev->vqs[n].masked_notifier);
+ } else {
+ file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
+ }
+ r = ioctl(hdev->control, VHOST_SET_VRING_CALL, &file);
+ assert(r >= 0);
+}
+
/* Host notifiers must be enabled at this point. */
int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
{
@@ -900,7 +969,7 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
goto fail_mem;
}
for (i = 0; i < hdev->nvqs; ++i) {
- r = vhost_virtqueue_init(hdev,
+ r = vhost_virtqueue_start(hdev,
vdev,
hdev->vqs + i,
i);
@@ -925,7 +994,7 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
fail_log:
fail_vq:
while (--i >= 0) {
- vhost_virtqueue_cleanup(hdev,
+ vhost_virtqueue_stop(hdev,
vdev,
hdev->vqs + i,
i);
@@ -946,7 +1015,7 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
int i, r;
for (i = 0; i < hdev->nvqs; ++i) {
- vhost_virtqueue_cleanup(hdev,
+ vhost_virtqueue_stop(hdev,
vdev,
hdev->vqs + i,
i);
diff --git a/hw/vhost.h b/hw/vhost.h
index 6f6a906..44c61a5 100644
--- a/hw/vhost.h
+++ b/hw/vhost.h
@@ -18,6 +18,7 @@ struct vhost_virtqueue {
void *ring;
unsigned long long ring_phys;
unsigned ring_size;
+ EventNotifier masked_notifier;
};
typedef unsigned long vhost_log_chunk_t;
@@ -53,4 +54,13 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev);
int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev);
void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev);
+/* Test and clear masked event pending status.
+ * Should be called after unmask to avoid losing events.
+ */
+bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n);
+
+/* Mask/unmask events from this vq.
+ */
+void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
+ bool mask);
#endif
diff --git a/hw/vhost_net.c b/hw/vhost_net.c
index ae2785d..d3a04ca 100644
--- a/hw/vhost_net.c
+++ b/hw/vhost_net.c
@@ -109,6 +109,9 @@ struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
(1 << VHOST_NET_F_VIRTIO_NET_HDR);
net->backend = r;
+ net->dev.nvqs = 2;
+ net->dev.vqs = net->vqs;
+
r = vhost_dev_init(&net->dev, devfd, "/dev/vhost-net", force);
if (r < 0) {
goto fail;
@@ -143,9 +146,6 @@ int vhost_net_start(struct vhost_net *net,
struct vhost_vring_file file = { };
int r;
- net->dev.nvqs = 2;
- net->dev.vqs = net->vqs;
-
r = vhost_dev_enable_notifiers(&net->dev, dev);
if (r < 0) {
goto fail_notifiers;
@@ -200,6 +200,17 @@ void vhost_net_cleanup(struct vhost_net *net)
vhost_dev_cleanup(&net->dev);
g_free(net);
}
+
+bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
+{
+ return vhost_virtqueue_pending(&net->dev, idx);
+}
+
+void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
+ int idx, bool mask)
+{
+ vhost_virtqueue_mask(&net->dev, dev, idx, mask);
+}
#else
struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
bool force)
@@ -234,4 +245,14 @@ unsigned vhost_net_get_features(struct vhost_net *net, unsigned features)
void vhost_net_ack_features(struct vhost_net *net, unsigned features)
{
}
+
+bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
+{
+ return -ENOSYS;
+}
+
+void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
+ int idx, bool mask)
+{
+}
#endif
diff --git a/hw/vhost_net.h b/hw/vhost_net.h
index 012aba4..88912b8 100644
--- a/hw/vhost_net.h
+++ b/hw/vhost_net.h
@@ -17,4 +17,7 @@ void vhost_net_cleanup(VHostNetState *net);
unsigned vhost_net_get_features(VHostNetState *net, unsigned features);
void vhost_net_ack_features(VHostNetState *net, unsigned features);
+bool vhost_net_virtqueue_pending(VHostNetState *net, int n);
+void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
+ int idx, bool mask);
#endif
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index b756d57..3bb01b1 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -1010,6 +1010,22 @@ static NetClientInfo net_virtio_info = {
.link_status_changed = virtio_net_set_link_status,
};
+static bool virtio_net_guest_notifier_pending(VirtIODevice *vdev, int idx)
+{
+ VirtIONet *n = to_virtio_net(vdev);
+ assert(n->vhost_started);
+ return vhost_net_virtqueue_pending(tap_get_vhost_net(n->nic->nc.peer), idx);
+}
+
+static void virtio_net_guest_notifier_mask(VirtIODevice *vdev, int idx,
+ bool mask)
+{
+ VirtIONet *n = to_virtio_net(vdev);
+ assert(n->vhost_started);
+ vhost_net_virtqueue_mask(tap_get_vhost_net(n->nic->nc.peer),
+ vdev, idx, mask);
+}
+
VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf,
virtio_net_conf *net)
{
@@ -1026,6 +1042,8 @@ VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf,
n->vdev.bad_features = virtio_net_bad_features;
n->vdev.reset = virtio_net_reset;
n->vdev.set_status = virtio_net_set_status;
+ n->vdev.guest_notifier_mask = virtio_net_guest_notifier_mask;
+ n->vdev.guest_notifier_pending = virtio_net_guest_notifier_pending;
n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);
if (net->tx && strcmp(net->tx, "timer") && strcmp(net->tx, "bh")) {
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* [Qemu-devel] [PATCH 6/8] virtio-net: set/clear vhost_started in reverse order
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
` (5 preceding siblings ...)
2012-12-26 10:52 ` [Qemu-devel] [PATCH 8/8] vhost: backend masking support Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
2012-12-26 10:52 ` [Qemu-devel] [PATCH 7/8] vhost: set started flag while start is in progress Michael S. Tsirkin
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
As vhost started is cleared last thing on stop,
set it first things on start. This makes it
possible to use vhost_started while start is in
progress which is used by follow-up patches.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/virtio-net.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 5d03b31..b756d57 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -126,12 +126,12 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)
if (!vhost_net_query(tap_get_vhost_net(n->nic->nc.peer), &n->vdev)) {
return;
}
+ n->vhost_started = 1;
r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
if (r < 0) {
error_report("unable to start vhost net: %d: "
"falling back on userspace virtio", -r);
- } else {
- n->vhost_started = 1;
+ n->vhost_started = 0;
}
} else {
vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread* [Qemu-devel] [PATCH 7/8] vhost: set started flag while start is in progress
2012-12-26 10:52 [Qemu-devel] [PATCH 0/8] virtio-pci: msix masking optimizations Michael S. Tsirkin
` (6 preceding siblings ...)
2012-12-26 10:52 ` [Qemu-devel] [PATCH 6/8] virtio-net: set/clear vhost_started in reverse order Michael S. Tsirkin
@ 2012-12-26 10:52 ` Michael S. Tsirkin
7 siblings, 0 replies; 10+ messages in thread
From: Michael S. Tsirkin @ 2012-12-26 10:52 UTC (permalink / raw)
To: qemu-devel, asias, stefanha
This makes it possible to use started flag for sanity checking
of callbacks that happen during start/stop.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
hw/vhost.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/hw/vhost.c b/hw/vhost.c
index b6d73ca..4fa5007 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -873,6 +873,9 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
{
int i, r;
+
+ hdev->started = true;
+
if (!vdev->binding->set_guest_notifiers) {
fprintf(stderr, "binding does not support guest notifiers\n");
r = -ENOSYS;
@@ -918,8 +921,6 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
}
}
- hdev->started = true;
-
return 0;
fail_log:
fail_vq:
@@ -934,6 +935,8 @@ fail_features:
vdev->binding->set_guest_notifiers(vdev->binding_opaque, hdev->nvqs, false);
fail_notifiers:
fail:
+
+ hdev->started = false;
return r;
}
--
MST
^ permalink raw reply related [flat|nested] 10+ messages in thread