Commit e8c81b4d authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Peter Maydell
Browse files

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: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent ed911435

tests/libqos/virtio.c

+22 −0
Original line number Diff line number Diff line
@@ -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)

{

tests/libqos/virtio.h

+5 −0
Original line number Diff line number Diff line
@@ -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,

tests/virtio-blk-test.c

+4 −4
Original line number Diff line number Diff line
@@ -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);