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authorMarc-André Lureau <marcandre.lureau@redhat.com>2015-07-09 15:50:13 +0200
committerMarc-André Lureau <marcandre.lureau@redhat.com>2015-10-26 10:19:53 +0100
commit660c97eef6f8f416c5dc24d3798e29f9f9f698fb (patch)
tree95f4b91be28e1b2f05925e65a3fe70d32760b83b /hw
parent0f57350e5c2ee0c6fe979f4d4b6d4e1de0c26e46 (diff)
ivshmem: use kvm irqfd for msi notifications
Use irqfd for improving context switch when notifying the guest. If the host doesn't support kvm irqfd, regular msi notifications are still supported. Note: the ivshmem implementation doesn't allow switching between MSI and IO interrupts, this patch doesn't either. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/misc/ivshmem.c180
1 files changed, 174 insertions, 6 deletions
diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index c6be33c2ef..e9dae834da 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -19,6 +19,7 @@
#include "hw/hw.h"
#include "hw/i386/pc.h"
#include "hw/pci/pci.h"
+#include "hw/pci/msi.h"
#include "hw/pci/msix.h"
#include "sysemu/kvm.h"
#include "migration/migration.h"
@@ -68,6 +69,7 @@ typedef struct Peer {
typedef struct MSIVector {
PCIDevice *pdev;
+ int virq;
} MSIVector;
typedef struct IVShmemState {
@@ -293,13 +295,73 @@ static void fake_irqfd(void *opaque, const uint8_t *buf, int size) {
msix_notify(pdev, vector);
}
+static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector,
+ MSIMessage msg)
+{
+ IVShmemState *s = IVSHMEM(dev);
+ EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
+ MSIVector *v = &s->msi_vectors[vector];
+ int ret;
+
+ IVSHMEM_DPRINTF("vector unmask %p %d\n", dev, vector);
+
+ ret = kvm_irqchip_update_msi_route(kvm_state, v->virq, msg, dev);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL, v->virq);
+}
+
+static void ivshmem_vector_mask(PCIDevice *dev, unsigned vector)
+{
+ IVShmemState *s = IVSHMEM(dev);
+ EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
+ int ret;
+
+ IVSHMEM_DPRINTF("vector mask %p %d\n", dev, vector);
+
+ ret = kvm_irqchip_remove_irqfd_notifier_gsi(kvm_state, n,
+ s->msi_vectors[vector].virq);
+ if (ret != 0) {
+ error_report("remove_irqfd_notifier_gsi failed");
+ }
+}
+
+static void ivshmem_vector_poll(PCIDevice *dev,
+ unsigned int vector_start,
+ unsigned int vector_end)
+{
+ IVShmemState *s = IVSHMEM(dev);
+ unsigned int vector;
+
+ IVSHMEM_DPRINTF("vector poll %p %d-%d\n", dev, vector_start, vector_end);
+
+ vector_end = MIN(vector_end, s->vectors);
+
+ for (vector = vector_start; vector < vector_end; vector++) {
+ EventNotifier *notifier = &s->peers[s->vm_id].eventfds[vector];
+
+ if (!msix_is_masked(dev, vector)) {
+ continue;
+ }
+
+ if (event_notifier_test_and_clear(notifier)) {
+ msix_set_pending(dev, vector);
+ }
+ }
+}
+
static CharDriverState* create_eventfd_chr_device(void * opaque, EventNotifier *n,
int vector)
{
/* create a event character device based on the passed eventfd */
IVShmemState *s = opaque;
- CharDriverState * chr;
+ PCIDevice *pdev = PCI_DEVICE(s);
int eventfd = event_notifier_get_fd(n);
+ CharDriverState *chr;
+
+ s->msi_vectors[vector].pdev = pdev;
chr = qemu_chr_open_eventfd(eventfd);
@@ -484,6 +546,58 @@ static bool fifo_update_and_get(IVShmemState *s, const uint8_t *buf, int size,
return true;
}
+static int ivshmem_add_kvm_msi_virq(IVShmemState *s, int vector)
+{
+ PCIDevice *pdev = PCI_DEVICE(s);
+ MSIMessage msg = msix_get_message(pdev, vector);
+ int ret;
+
+ IVSHMEM_DPRINTF("ivshmem_add_kvm_msi_virq vector:%d\n", vector);
+
+ if (s->msi_vectors[vector].pdev != NULL) {
+ return 0;
+ }
+
+ ret = kvm_irqchip_add_msi_route(kvm_state, msg, pdev);
+ if (ret < 0) {
+ error_report("ivshmem: kvm_irqchip_add_msi_route failed");
+ return -1;
+ }
+
+ s->msi_vectors[vector].virq = ret;
+ s->msi_vectors[vector].pdev = pdev;
+
+ return 0;
+}
+
+static void setup_interrupt(IVShmemState *s, int vector)
+{
+ EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
+ bool with_irqfd = kvm_msi_via_irqfd_enabled() &&
+ ivshmem_has_feature(s, IVSHMEM_MSI);
+ PCIDevice *pdev = PCI_DEVICE(s);
+
+ IVSHMEM_DPRINTF("setting up interrupt for vector: %d\n", vector);
+
+ if (!with_irqfd) {
+ IVSHMEM_DPRINTF("with eventfd");
+ s->eventfd_chr[vector] = create_eventfd_chr_device(s, n, vector);
+ } else if (msix_enabled(pdev)) {
+ IVSHMEM_DPRINTF("with irqfd");
+ if (ivshmem_add_kvm_msi_virq(s, vector) < 0) {
+ return;
+ }
+
+ if (!msix_is_masked(pdev, vector)) {
+ kvm_irqchip_add_irqfd_notifier_gsi(kvm_state, n, NULL,
+ s->msi_vectors[vector].virq);
+ }
+ } else {
+ /* it will be delayed until msix is enabled, in write_config */
+ IVSHMEM_DPRINTF("with irqfd, delayed until msix enabled");
+ }
+}
+
static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
{
IVShmemState *s = opaque;
@@ -586,11 +700,10 @@ static void ivshmem_read(void *opaque, const uint8_t *buf, int size)
IVSHMEM_DPRINTF("eventfds[%ld][%d] = %d\n", incoming_posn,
new_eventfd, incoming_fd);
event_notifier_init_fd(&peer->eventfds[new_eventfd], incoming_fd);
+ fcntl_setfl(incoming_fd, O_NONBLOCK); /* msix/irqfd poll non block */
if (incoming_posn == s->vm_id) {
- s->eventfd_chr[new_eventfd] = create_eventfd_chr_device(s,
- &s->peers[s->vm_id].eventfds[new_eventfd],
- new_eventfd);
+ setup_interrupt(s, new_eventfd);
}
if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
@@ -665,10 +778,65 @@ static int ivshmem_setup_msi(IVShmemState * s)
return 0;
}
-static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address,
+static void ivshmem_enable_irqfd(IVShmemState *s)
+{
+ PCIDevice *pdev = PCI_DEVICE(s);
+ int i;
+
+ for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
+ ivshmem_add_kvm_msi_virq(s, i);
+ }
+
+ if (msix_set_vector_notifiers(pdev,
+ ivshmem_vector_unmask,
+ ivshmem_vector_mask,
+ ivshmem_vector_poll)) {
+ error_report("ivshmem: msix_set_vector_notifiers failed");
+ }
+}
+
+static void ivshmem_remove_kvm_msi_virq(IVShmemState *s, int vector)
+{
+ IVSHMEM_DPRINTF("ivshmem_remove_kvm_msi_virq vector:%d\n", vector);
+
+ if (s->msi_vectors[vector].pdev == NULL) {
+ return;
+ }
+
+ /* it was cleaned when masked in the frontend. */
+ kvm_irqchip_release_virq(kvm_state, s->msi_vectors[vector].virq);
+
+ s->msi_vectors[vector].pdev = NULL;
+}
+
+static void ivshmem_disable_irqfd(IVShmemState *s)
+{
+ PCIDevice *pdev = PCI_DEVICE(s);
+ int i;
+
+ for (i = 0; i < s->peers[s->vm_id].nb_eventfds; i++) {
+ ivshmem_remove_kvm_msi_virq(s, i);
+ }
+
+ msix_unset_vector_notifiers(pdev);
+}
+
+static void ivshmem_write_config(PCIDevice *pdev, uint32_t address,
uint32_t val, int len)
{
- pci_default_write_config(pci_dev, address, val, len);
+ IVShmemState *s = IVSHMEM(pdev);
+ int is_enabled, was_enabled = msix_enabled(pdev);
+
+ pci_default_write_config(pdev, address, val, len);
+ is_enabled = msix_enabled(pdev);
+
+ if (kvm_msi_via_irqfd_enabled() && s->vm_id != -1) {
+ if (!was_enabled && is_enabled) {
+ ivshmem_enable_irqfd(s);
+ } else if (was_enabled && !is_enabled) {
+ ivshmem_disable_irqfd(s);
+ }
+ }
}
static void pci_ivshmem_realize(PCIDevice *dev, Error **errp)