[PATCH v2 07/11] vfio: selftests: Allow drivers to specify required region size

[Jason Gunthorpe <jgg@nvidia.com>]

Add a region_size field to struct vfio_pci_driver_ops so drivers can
declare how much DMA-mapped region they need. The mlx5 driver will need
~18MB for firmware pages. Existing drivers pass in the sizeof their state
struct. The core code will round up and minimize it to SZ_2M so as not to
change any test behavior.

Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c         | 1 +
 tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c       | 1 +
 .../selftests/vfio/lib/include/libvfio/vfio_pci_driver.h   | 6 ++++++
 tools/testing/selftests/vfio/vfio_pci_driver_test.c        | 7 ++++++-
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c b/tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c
index 19d9630b24c23f..40b8541b588eee 100644
--- a/tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c
+++ b/tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c
@@ -418,6 +418,7 @@ static void dsa_send_msi(struct vfio_pci_device *device)
 
 const struct vfio_pci_driver_ops dsa_ops = {
 	.name = "dsa",
+	.region_size = sizeof(struct dsa_state),
 	.probe = dsa_probe,
 	.init = dsa_init,
 	.remove = dsa_remove,
diff --git a/tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c b/tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c
index a871b935542bad..c9b28365c5eb6b 100644
--- a/tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c
+++ b/tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c
@@ -226,6 +226,7 @@ static void ioat_send_msi(struct vfio_pci_device *device)
 
 const struct vfio_pci_driver_ops ioat_ops = {
 	.name = "ioat",
+	.region_size = sizeof(struct ioat_state),
 	.probe = ioat_probe,
 	.init = ioat_init,
 	.remove = ioat_remove,
diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h
index e5ada209b1d102..547369c5cff95a 100644
--- a/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h
+++ b/tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_driver.h
@@ -9,6 +9,12 @@ struct vfio_pci_device;
 struct vfio_pci_driver_ops {
 	const char *name;
 
+	/*
+	 * Size of the driver's state structure overlaid on
+	 * device->driver.region.vaddr
+	 */
+	u64 region_size;
+
 	/**
 	 * @probe() - Check if the driver supports the given device.
 	 *
diff --git a/tools/testing/selftests/vfio/vfio_pci_driver_test.c b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
index afa0480ddd9b2a..5a46800cde4c8d 100644
--- a/tools/testing/selftests/vfio/vfio_pci_driver_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
@@ -2,6 +2,7 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 
+#include <linux/log2.h>
 #include <linux/sizes.h>
 #include <linux/vfio.h>
 
@@ -80,7 +81,11 @@ FIXTURE_SETUP(vfio_pci_driver_test)
 	driver = &self->device->driver;
 
 	region_setup(self->iommu, self->iova_allocator, &self->memcpy_region, SZ_1G);
-	region_setup(self->iommu, self->iova_allocator, &driver->region, SZ_2M);
+
+	VFIO_ASSERT_NE(driver->ops->region_size, 0);
+	region_setup(self->iommu, self->iova_allocator, &driver->region,
+		     max_t(u64, roundup_pow_of_two(driver->ops->region_size),
+			   SZ_2M));
 
 	/* Any IOVA that doesn't overlap memcpy_region and driver->region. */
 	self->unmapped_iova = iova_allocator_alloc(self->iova_allocator, SZ_1G);
-- 
2.43.0