vfio: sefltests: Add vfio_pci_driver_test

Add a new selftest that tests all driver operations. This test serves
both as a demonstration of the driver framework, and also as a
correctness test for future drivers.

Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20250822212518.4156428-14-dmatlack@google.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

tools/testing/selftests/vfio/Makefile

@@ -2,6 +2,7 @@ CFLAGS = $(KHDR_INCLUDES)
 TEST_GEN_PROGS += vfio_dma_mapping_test
 TEST_GEN_PROGS += vfio_iommufd_setup_test
 TEST_GEN_PROGS += vfio_pci_device_test
+TEST_GEN_PROGS += vfio_pci_driver_test
 include ../lib.mk
 include lib/libvfio.mk
 

tools/testing/selftests/vfio/vfio_pci_driver_test.c

@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include <linux/sizes.h>
+#include <linux/vfio.h>
+
+#include <vfio_util.h>
+
+#include "../kselftest_harness.h"
+
+static const char *device_bdf;
+
+#define ASSERT_NO_MSI(_eventfd) do {			\
+	u64 __value;					\
+							\
+	ASSERT_EQ(-1, read(_eventfd, &__value, 8));	\
+	ASSERT_EQ(EAGAIN, errno);			\
+} while (0)
+
+static void region_setup(struct vfio_pci_device *device,
+			 struct vfio_dma_region *region, u64 size)
+{
+	const int flags = MAP_SHARED | MAP_ANONYMOUS;
+	const int prot = PROT_READ | PROT_WRITE;
+	void *vaddr;
+
+	vaddr = mmap(NULL, size, prot, flags, -1, 0);
+	VFIO_ASSERT_NE(vaddr, MAP_FAILED);
+
+	region->vaddr = vaddr;
+	region->iova = (u64)vaddr;
+	region->size = size;
+
+	vfio_pci_dma_map(device, region);
+}
+
+static void region_teardown(struct vfio_pci_device *device,
+			    struct vfio_dma_region *region)
+{
+	vfio_pci_dma_unmap(device, region);
+	VFIO_ASSERT_EQ(munmap(region->vaddr, region->size), 0);
+}
+
+FIXTURE(vfio_pci_driver_test) {
+	struct vfio_pci_device *device;
+	struct vfio_dma_region memcpy_region;
+	void *vaddr;
+	int msi_fd;
+
+	u64 size;
+	void *src;
+	void *dst;
+	iova_t src_iova;
+	iova_t dst_iova;
+	iova_t unmapped_iova;
+};
+
+FIXTURE_SETUP(vfio_pci_driver_test)
+{
+	struct vfio_pci_driver *driver;
+
+	self->device = vfio_pci_device_init(device_bdf, VFIO_TYPE1_IOMMU);
+
+	driver = &self->device->driver;
+
+	region_setup(self->device, &self->memcpy_region, SZ_1G);
+	region_setup(self->device, &driver->region, SZ_2M);
+
+	/* Any IOVA that doesn't overlap memcpy_region and driver->region. */
+	self->unmapped_iova = 8UL * SZ_1G;
+
+	vfio_pci_driver_init(self->device);
+	self->msi_fd = self->device->msi_eventfds[driver->msi];
+
+	/*
+	 * Use the maximum size supported by the device for memcpy operations,
+	 * slimmed down to fit into the memcpy region (divided by 2 so src and
+	 * dst regions do not overlap).
+	 */
+	self->size = self->device->driver.max_memcpy_size;
+	self->size = min(self->size, self->memcpy_region.size / 2);
+
+	self->src = self->memcpy_region.vaddr;
+	self->dst = self->src + self->size;
+
+	self->src_iova = to_iova(self->device, self->src);
+	self->dst_iova = to_iova(self->device, self->dst);
+}
+
+FIXTURE_TEARDOWN(vfio_pci_driver_test)
+{
+	struct vfio_pci_driver *driver = &self->device->driver;
+
+	vfio_pci_driver_remove(self->device);
+
+	region_teardown(self->device, &self->memcpy_region);
+	region_teardown(self->device, &driver->region);
+
+	vfio_pci_device_cleanup(self->device);
+}
+
+TEST_F(vfio_pci_driver_test, init_remove)
+{
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		vfio_pci_driver_remove(self->device);
+		vfio_pci_driver_init(self->device);
+	}
+}
+
+TEST_F(vfio_pci_driver_test, memcpy_success)
+{
+	fcntl_set_nonblock(self->msi_fd);
+
+	memset(self->src, 'x', self->size);
+	memset(self->dst, 'y', self->size);
+
+	ASSERT_EQ(0, vfio_pci_driver_memcpy(self->device,
+					    self->src_iova,
+					    self->dst_iova,
+					    self->size));
+
+	ASSERT_EQ(0, memcmp(self->src, self->dst, self->size));
+	ASSERT_NO_MSI(self->msi_fd);
+}
+
+TEST_F(vfio_pci_driver_test, memcpy_from_unmapped_iova)
+{
+	fcntl_set_nonblock(self->msi_fd);
+
+	/*
+	 * Ignore the return value since not all devices will detect and report
+	 * accesses to unmapped IOVAs as errors.
+	 */
+	vfio_pci_driver_memcpy(self->device, self->unmapped_iova,
+			       self->dst_iova, self->size);
+
+	ASSERT_NO_MSI(self->msi_fd);
+}
+
+TEST_F(vfio_pci_driver_test, memcpy_to_unmapped_iova)
+{
+	fcntl_set_nonblock(self->msi_fd);
+
+	/*
+	 * Ignore the return value since not all devices will detect and report
+	 * accesses to unmapped IOVAs as errors.
+	 */
+	vfio_pci_driver_memcpy(self->device, self->src_iova,
+			       self->unmapped_iova, self->size);
+
+	ASSERT_NO_MSI(self->msi_fd);
+}
+
+TEST_F(vfio_pci_driver_test, send_msi)
+{
+	u64 value;
+
+	vfio_pci_driver_send_msi(self->device);
+	ASSERT_EQ(8, read(self->msi_fd, &value, 8));
+	ASSERT_EQ(1, value);
+}
+
+TEST_F(vfio_pci_driver_test, mix_and_match)
+{
+	u64 value;
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		memset(self->src, 'x', self->size);
+		memset(self->dst, 'y', self->size);
+
+		ASSERT_EQ(0, vfio_pci_driver_memcpy(self->device,
+						    self->src_iova,
+						    self->dst_iova,
+						    self->size));
+
+		ASSERT_EQ(0, memcmp(self->src, self->dst, self->size));
+
+		vfio_pci_driver_memcpy(self->device,
+				       self->unmapped_iova,
+				       self->dst_iova,
+				       self->size);
+
+		vfio_pci_driver_send_msi(self->device);
+		ASSERT_EQ(8, read(self->msi_fd, &value, 8));
+		ASSERT_EQ(1, value);
+	}
+}
+
+TEST_F_TIMEOUT(vfio_pci_driver_test, memcpy_storm, 60)
+{
+	struct vfio_pci_driver *driver = &self->device->driver;
+	u64 total_size;
+	u64 count;
+
+	fcntl_set_nonblock(self->msi_fd);
+
+	/*
+	 * Perform up to 250GiB worth of DMA reads and writes across several
+	 * memcpy operations. Some devices can support even more but the test
+	 * will take too long.
+	 */
+	total_size = 250UL * SZ_1G;
+	count = min(total_size / self->size, driver->max_memcpy_count);
+
+	printf("Kicking off %lu memcpys of size 0x%lx\n", count, self->size);
+	vfio_pci_driver_memcpy_start(self->device,
+				     self->src_iova,
+				     self->dst_iova,
+				     self->size, count);
+
+	ASSERT_EQ(0, vfio_pci_driver_memcpy_wait(self->device));
+	ASSERT_NO_MSI(self->msi_fd);
+}
+
+int main(int argc, char *argv[])
+{
+	struct vfio_pci_device *device;
+
+	device_bdf = vfio_selftests_get_bdf(&argc, argv);
+
+	device = vfio_pci_device_init(device_bdf, VFIO_TYPE1_IOMMU);
+	if (!device->driver.ops) {
+		fprintf(stderr, "No driver found for device %s\n", device_bdf);
+		return KSFT_SKIP;
+	}
+	vfio_pci_device_cleanup(device);
+
+	return test_harness_run(argc, argv);
+}