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ivshmem: use a single eventfd callback, get rid of CharDriver 

Simplify the interrupt handling by having a single callback on irq&msi
cases. Remove usage of CharDriver, replace it with
qemu_set_fd_handler(). Use event_notifier_test_and_clear() to read the
eventfd.

Before this patch, ivshmem writes the first byte received to
s->intrstatus. But ivshmem_device_spec.txt says "The status register is
set to 1 when an interrupt occurs." Fortunately, the byte usually comes
from another ivshmem device, and those always write 1.

After this commit, follows the specification, set to 1 when an interrupt
occurs.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Marc-André Lureau 2015-12-21 12:10:13 +01:00
parent fd47bfe5ad
commit 9940c3236f
1 changed files with 18 additions and 37 deletions
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55
hw/misc/ivshmem.c
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@ -263,15 +263,6 @@ static const MemoryRegionOps ivshmem_mmio_ops = {
},
};
static void ivshmem_receive(void *opaque, const uint8_t *buf, int size)
{
IVShmemState *s = opaque;
IVSHMEM_DPRINTF("ivshmem_receive 0x%02x size: %d\n", *buf, size);
ivshmem_IntrStatus_write(s, *buf);
}
static int ivshmem_can_receive(void * opaque)
{
return sizeof(int64_t);
@ -282,15 +273,24 @@ static void ivshmem_event(void *opaque, int event)
IVSHMEM_DPRINTF("ivshmem_event %d\n", event);
}
static void fake_irqfd(void *opaque, const uint8_t *buf, int size) {
static void ivshmem_vector_notify(void *opaque)
{
MSIVector *entry = opaque;
PCIDevice *pdev = entry->pdev;
IVShmemState *s = IVSHMEM(pdev);
int vector = entry - s->msi_vectors;
EventNotifier *n = &s->peers[s->vm_id].eventfds[vector];
if (!event_notifier_test_and_clear(n)) {
return;
}
IVSHMEM_DPRINTF("interrupt on vector %p %d\n", pdev, vector);
msix_notify(pdev, vector);
if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
msix_notify(pdev, vector);
} else {
ivshmem_IntrStatus_write(s, 1);
}
}
static int ivshmem_vector_unmask(PCIDevice *dev, unsigned vector,
@ -350,35 +350,16 @@ static void ivshmem_vector_poll(PCIDevice *dev,
}
}
static CharDriverState* create_eventfd_chr_device(IVShmemState *s,
EventNotifier *n,
int vector)
static void watch_vector_notifier(IVShmemState *s, EventNotifier *n,
int vector)
{
/* create a event character device based on the passed eventfd */
int eventfd = event_notifier_get_fd(n);
CharDriverState *chr;
chr = qemu_chr_open_eventfd(eventfd);
if (chr == NULL) {
error_report("creating chardriver for eventfd %d failed", eventfd);
return NULL;
}
qemu_chr_fe_claim_no_fail(chr);
/* if MSI is supported we need multiple interrupts */
if (ivshmem_has_feature(s, IVSHMEM_MSI)) {
s->msi_vectors[vector].pdev = PCI_DEVICE(s);
qemu_chr_add_handlers(chr, ivshmem_can_receive, fake_irqfd,
ivshmem_event, &s->msi_vectors[vector]);
} else {
qemu_chr_add_handlers(chr, ivshmem_can_receive, ivshmem_receive,
ivshmem_event, s);
}
return chr;
s->msi_vectors[vector].pdev = PCI_DEVICE(s);
qemu_set_fd_handler(eventfd, ivshmem_vector_notify,
NULL, &s->msi_vectors[vector]);
}
static int check_shm_size(IVShmemState *s, int fd, Error **errp)
@ -588,7 +569,7 @@ static void setup_interrupt(IVShmemState *s, int vector)
if (!with_irqfd) {
IVSHMEM_DPRINTF("with eventfd");
s->eventfd_chr[vector] = create_eventfd_chr_device(s, n, vector);
watch_vector_notifier(s, n, vector);
} else if (msix_enabled(pdev)) {
IVSHMEM_DPRINTF("with irqfd");
if (ivshmem_add_kvm_msi_virq(s, vector) < 0) {