From 9940c3236f318949c92099163281d5d23a9fcf4f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Mon, 21 Dec 2015 12:10:13 +0100 Subject: [PATCH] ivshmem: use a single eventfd callback, get rid of CharDriver MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Markus Armbruster --- hw/misc/ivshmem.c | 55 ++++++++++++++++------------------------------- 1 file changed, 18 insertions(+), 37 deletions(-) diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c index 5f33149c91..48b7a34a8f 100644 --- a/hw/misc/ivshmem.c +++ b/hw/misc/ivshmem.c @@ -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) {