[PATCH RFC v3 74/88] KVM: selftests: Verify VFIO IRQ info for igb device

[Ackerley Tng via B4 Relay]

From: Ackerley Tng <ackerleytng@xxxxxxxxxx>

Add a subtest to verify interrupt capability queries on the bound
Intel 82576 device.

Check that MSI-X reports a positive vector count with eventfd signaling
support, that MSI reports eventfd capability, and that INTx reports
eventfd support along with maskable and auto-masked flags when present.

Testing multiple interrupt types establishes baseline checks on the
underlying device descriptor so that when VFIO resources are later
delegated to or wrapped by guest_memfd, native capability querying on
the device descriptor remains unaffected.
---
 .../selftests/kvm/x86/guest_memfd_vfio_test.c      | 48 ++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_vfio_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_vfio_test.c
index c76abe6d45140..6525f392b3930 100644
--- a/tools/testing/selftests/kvm/x86/guest_memfd_vfio_test.c
+++ b/tools/testing/selftests/kvm/x86/guest_memfd_vfio_test.c
@@ -188,4 +188,52 @@ TEST_F(guest_memfd_vfio, get_region_info)
 				    VFIO_REGION_INFO_FLAG_WRITE));
 }
 
+TEST_F(guest_memfd_vfio, get_irq_info)
+{
+	struct vfio_irq_info irq_info = {};
+	int ret;
+
+	/*
+	 * Test MSI-X interrupts (VFIO_PCI_MSIX_IRQ_INDEX):
+	 * Intel 82576 supports up to 10 MSI-X vectors.
+	 */
+	irq_info.argsz = sizeof(irq_info);
+	irq_info.index = VFIO_PCI_MSIX_IRQ_INDEX;
+	ret = ioctl(self->vfio_fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
+	ASSERT_EQ(0, ret);
+	ASSERT_GT(irq_info.count, 0);
+	ASSERT_TRUE(irq_info.flags & VFIO_IRQ_INFO_EVENTFD);
+
+	/*
+	 * Test MSI interrupts (VFIO_PCI_MSI_IRQ_INDEX):
+	 * Should report eventfd capability.
+	 */
+	memset(&irq_info, 0, sizeof(irq_info));
+	irq_info.argsz = sizeof(irq_info);
+	irq_info.index = VFIO_PCI_MSI_IRQ_INDEX;
+	ret = ioctl(self->vfio_fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
+	ASSERT_EQ(0, ret);
+	ASSERT_GT(irq_info.count, 0);
+	ASSERT_TRUE(irq_info.flags & VFIO_IRQ_INFO_EVENTFD);
+
+	/*
+	 * Test legacy INTx interrupts (VFIO_PCI_INTX_IRQ_INDEX):
+	 * Must support eventfd and masking when present.
+	 */
+	memset(&irq_info, 0, sizeof(irq_info));
+	irq_info.argsz = sizeof(irq_info);
+	irq_info.index = VFIO_PCI_INTX_IRQ_INDEX;
+	ret = ioctl(self->vfio_fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
+	ASSERT_EQ(0, ret);
+	ASSERT_LE(irq_info.count, 1);
+	if (irq_info.count == 1) {
+		ASSERT_EQ(VFIO_IRQ_INFO_EVENTFD |
+			  VFIO_IRQ_INFO_MASKABLE |
+			  VFIO_IRQ_INFO_AUTOMASKED,
+			  irq_info.flags & (VFIO_IRQ_INFO_EVENTFD |
+					    VFIO_IRQ_INFO_MASKABLE |
+					    VFIO_IRQ_INFO_AUTOMASKED));
+	}
+}
+
 TEST_HARNESS_MAIN

-- 
2.56.0.455.g6c5a503b38-goog