From e8c81b4d8a5a2fd125e559cb02b8a87598419041 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 29 Sep 2014 16:40:11 +0100 Subject: 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 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'tests/libqos/virtio.c') 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) { -- cgit v1.2.3-55-g7522