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virtio-pci: cache msix messages 

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>
This commit is contained in:
Michael S. Tsirkin 2012-12-21 00:27:54 +02:00
parent 078bbb5040
commit 774345f981
2 changed files with 103 additions and 23 deletions
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125
hw/virtio-pci.c
View File

@ -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++;
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);
}
return ret;
}
return 0;
}
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 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_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 = msix_set_vector_notifiers(&proxy->pci_dev,
kvm_virtio_pci_vector_use,
kvm_virtio_pci_vector_release,
kvm_virtio_pci_vector_poll);
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_unmask,
kvm_virtio_pci_vector_mask,
kvm_virtio_pci_vector_poll);
if (r < 0) {
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);

1
hw/virtio-pci.h
View File

@ -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;