[PATCH 3/9] qtest/e1000e|igb: assert irqs are clear before triggering an irq

[Nicholas Piggin <npiggin@gmail.com>]

Assert there is no existing irq raised that would lead to a false
positive interrupt test.

e1000e has to disable interrupt throttling for this test, because
it can cause delayed superfluous interrupts which trip the assertions.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 tests/qtest/libqos/e1000e.h |  1 +
 tests/qtest/e1000e-test.c   | 10 ++++++++++
 tests/qtest/igb-test.c      |  6 ++++++
 tests/qtest/libqos/e1000e.c |  9 ++++++++-
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/tests/qtest/libqos/e1000e.h b/tests/qtest/libqos/e1000e.h
index 30643c80949..7154aec0339 100644
--- a/tests/qtest/libqos/e1000e.h
+++ b/tests/qtest/libqos/e1000e.h
@@ -54,6 +54,7 @@ static inline uint32_t e1000e_macreg_read(QE1000E *d, uint32_t reg)
     return qpci_io_readl(&d_pci->pci_dev, d_pci->mac_regs, reg);
 }
 
+bool e1000e_seen_isr(QE1000E *d, uint16_t msg_id);
 void e1000e_wait_isr(QE1000E *d, uint16_t msg_id);
 void e1000e_tx_ring_push(QE1000E *d, void *descr);
 void e1000e_rx_ring_push(QE1000E *d, void *descr);
diff --git a/tests/qtest/e1000e-test.c b/tests/qtest/e1000e-test.c
index 746d26cfb67..9ab81ecff5b 100644
--- a/tests/qtest/e1000e-test.c
+++ b/tests/qtest/e1000e-test.c
@@ -61,6 +61,9 @@ static void e1000e_send_verify(QE1000E *d, int *test_sockets, QGuestAllocator *a
                                    E1000_TXD_DTYP_D   |
                                    sizeof(buffer));
 
+    /* Ensure the interrupt has not been taken already */
+    g_assert(!e1000e_seen_isr(d, E1000E_TX0_MSG_ID));
+
     /* Put descriptor to the ring */
     e1000e_tx_ring_push(d, &descr);
 
@@ -105,6 +108,9 @@ static void e1000e_receive_verify(QE1000E *d, int *test_sockets, QGuestAllocator
     char buffer[64];
     int ret;
 
+    /* Ensure the interrupt has not been taken already */
+    g_assert(!e1000e_seen_isr(d, E1000E_RX0_MSG_ID));
+
     /* Send a dummy packet to device's socket*/
     ret = iov_send(test_sockets[0], iov, 2, 0, sizeof(len) + sizeof(packet));
     g_assert_cmpint(ret, == , sizeof(packet) + sizeof(len));
@@ -188,6 +194,10 @@ static void test_e1000e_multiple_transfers(void *obj, void *data,
         return;
     }
 
+    /* Clear EITR because buggy QEMU throttle timer causes superfluous irqs */
+    e1000e_macreg_write(d, E1000_EITR + E1000E_RX0_MSG_ID * 4, 0);
+    e1000e_macreg_write(d, E1000_EITR + E1000E_TX0_MSG_ID * 4, 0);
+
     for (i = 0; i < iterations; i++) {
         e1000e_send_verify(d, data, alloc);
         e1000e_receive_verify(d, data, alloc);
diff --git a/tests/qtest/igb-test.c b/tests/qtest/igb-test.c
index cf8b4131cf2..1bbb4bea4c1 100644
--- a/tests/qtest/igb-test.c
+++ b/tests/qtest/igb-test.c
@@ -64,6 +64,9 @@ static void igb_send_verify(QE1000E *d, int *test_sockets, QGuestAllocator *allo
                                           E1000_TXD_DTYP_D   |
                                           sizeof(buffer));
 
+    /* Ensure the interrupt has not been taken already */
+    g_assert(!e1000e_seen_isr(d, E1000E_TX0_MSG_ID));
+
     /* Put descriptor to the ring */
     e1000e_tx_ring_push(d, &descr);
 
@@ -119,6 +122,9 @@ static void igb_receive_verify(QE1000E *d, int *test_sockets, QGuestAllocator *a
     memset(&descr, 0, sizeof(descr));
     descr.read.pkt_addr = cpu_to_le64(data);
 
+    /* Ensure the interrupt has not been taken already */
+    g_assert(!e1000e_seen_isr(d, E1000E_RX0_MSG_ID));
+
     /* Put descriptor to the ring */
     e1000e_rx_ring_push(d, &descr);
 
diff --git a/tests/qtest/libqos/e1000e.c b/tests/qtest/libqos/e1000e.c
index 925654c7fd4..4e4c387b0bf 100644
--- a/tests/qtest/libqos/e1000e.c
+++ b/tests/qtest/libqos/e1000e.c
@@ -77,13 +77,20 @@ static void e1000e_foreach_callback(QPCIDevice *dev, int devfn, void *data)
     g_free(dev);
 }
 
+bool e1000e_seen_isr(QE1000E *d, uint16_t msg_id)
+{
+    QE1000E_PCI *d_pci = container_of(d, QE1000E_PCI, e1000e);
+
+    return qpci_msix_pending(&d_pci->pci_dev, msg_id);
+}
+
 void e1000e_wait_isr(QE1000E *d, uint16_t msg_id)
 {
     QE1000E_PCI *d_pci = container_of(d, QE1000E_PCI, e1000e);
     guint64 end_time = g_get_monotonic_time() + 5 * G_TIME_SPAN_SECOND;
 
     do {
-        if (qpci_msix_pending(&d_pci->pci_dev, msg_id)) {
+        if (e1000e_seen_isr(d, msg_id)) {
             return;
         }
         qtest_clock_step(d_pci->pci_dev.bus->qts, 10000);
-- 
2.45.2