From e8c81b4d8a5a2fd125e559cb02b8a87598419041 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 29 Sep 2014 16:40:11 +0100 Subject: [PATCH] libqos: improve event_index test with timeout The virtio event_index feature lets the device driver tell the device how many requests to process before raising the next interrupt. virtio-blk-test.c tries to verify that the device does not raise an interrupt unnecessarily. Unfortunately the test has a race condition. It spins checking for an interrupt up to 100 times and then assumes the request has finished. On a slow host the I/O request could still be in flight and the test would fail. This patch waits for the request to complete, or until a 30-second timeout is reached. If an interrupt is raised while waiting the test fails since the device was not supposed to raise interrupts. Signed-off-by: Stefan Hajnoczi Signed-off-by: Peter Maydell --- tests/libqos/virtio.c | 22 ++++++++++++++++++++++ tests/libqos/virtio.h | 5 +++++ tests/virtio-blk-test.c | 8 ++++---- 3 files changed, 31 insertions(+), 4 deletions(-) diff --git a/tests/libqos/virtio.c b/tests/libqos/virtio.c index 9b6de2c0a7..009325dd02 100644 --- a/tests/libqos/virtio.c +++ b/tests/libqos/virtio.c @@ -91,6 +91,28 @@ bool qvirtio_wait_queue_isr(const QVirtioBus *bus, QVirtioDevice *d, return timeout != 0; } +/* Wait for the status byte at given guest memory address to be set + * + * The virtqueue interrupt must not be raised, making this useful for testing + * event_index functionality. + */ +uint8_t qvirtio_wait_status_byte_no_isr(const QVirtioBus *bus, + QVirtioDevice *d, + QVirtQueue *vq, + uint64_t addr, + gint64 timeout_us) +{ + gint64 start_time = g_get_monotonic_time(); + uint8_t val; + + while ((val = readb(addr)) == 0xff) { + clock_step(100); + g_assert(!bus->get_queue_isr_status(d, vq)); + g_assert(g_get_monotonic_time() - start_time <= timeout_us); + } + return val; +} + bool qvirtio_wait_config_isr(const QVirtioBus *bus, QVirtioDevice *d, uint64_t timeout) { diff --git a/tests/libqos/virtio.h b/tests/libqos/virtio.h index 70b3376360..bc7518e880 100644 --- a/tests/libqos/virtio.h +++ b/tests/libqos/virtio.h @@ -162,6 +162,11 @@ void qvirtio_set_driver_ok(const QVirtioBus *bus, QVirtioDevice *d); bool qvirtio_wait_queue_isr(const QVirtioBus *bus, QVirtioDevice *d, QVirtQueue *vq, uint64_t timeout); +uint8_t qvirtio_wait_status_byte_no_isr(const QVirtioBus *bus, + QVirtioDevice *d, + QVirtQueue *vq, + uint64_t addr, + gint64 timeout_us); bool qvirtio_wait_config_isr(const QVirtioBus *bus, QVirtioDevice *d, uint64_t timeout); QVirtQueue *qvirtqueue_setup(const QVirtioBus *bus, QVirtioDevice *d, diff --git a/tests/virtio-blk-test.c b/tests/virtio-blk-test.c index 588666cff1..0e3bfa7eb2 100644 --- a/tests/virtio-blk-test.c +++ b/tests/virtio-blk-test.c @@ -42,6 +42,7 @@ #define TEST_IMAGE_SIZE (64 * 1024 * 1024) #define QVIRTIO_BLK_TIMEOUT 100 +#define QVIRTIO_BLK_TIMEOUT_US (30 * 1000 * 1000) #define PCI_SLOT 0x04 #define PCI_FN 0x00 @@ -595,10 +596,9 @@ static void pci_idx(void) qvirtqueue_kick(&qvirtio_pci, &dev->vdev, &vqpci->vq, free_head); /* No notification expected */ - g_assert(!qvirtio_wait_queue_isr(&qvirtio_pci, &dev->vdev, &vqpci->vq, - QVIRTIO_BLK_TIMEOUT)); - - status = readb(req_addr + 528); + status = qvirtio_wait_status_byte_no_isr(&qvirtio_pci, &dev->vdev, + &vqpci->vq, req_addr + 528, + QVIRTIO_BLK_TIMEOUT_US); g_assert_cmpint(status, ==, 0); guest_free(alloc, req_addr); -- 2.11.0