vfio: selftests: Allow drivers to specify required region size

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. Since drivers all use only their declared state we can use the
value directly and remove the SZ_2M hard coding.

Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/6-v7-c6d30e8ce1e4+3dfa6-mlx5st_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

9 files changed, 22 insertions, 4 deletions

diff --git a/tools/testing/selftests/kvm/irq_test.c b/tools/testing/selftests/kvm/irq_test.c
index 168c52734fef..791e576c334c 100644
--- a/tools/testing/selftests/kvm/irq_test.c
+++ b/tools/testing/selftests/kvm/irq_test.c
@@ -6,7 +6,6 @@
 #include "proc_util.h"
 
 #include <libvfio.h>
-#include <linux/sizes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -101,7 +100,6 @@ static int vfio_setup_msi(struct vfio_pci_device *device)
 	allocator = iova_allocator_init(device->iommu);
 
 	region = &device->driver.region;
-	region->size = SZ_2M;
 	region->iova = iova_allocator_alloc(allocator, region->size);
 	region->vaddr = kvm_mmap(region->size, prot, flags, -1);
 	TEST_ASSERT(region->vaddr != MAP_FAILED, "mmap() failed\n");
diff --git a/tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c b/tools/testing/selftests/vfio/lib/drivers/dsa/dsa.c
index 19d9630b24c2..40b8541b588e 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/igb/igb.c b/tools/testing/selftests/vfio/lib/drivers/igb/igb.c
index fd9e05d77ea4..2fafcc9f51c0 100644
--- a/tools/testing/selftests/vfio/lib/drivers/igb/igb.c
+++ b/tools/testing/selftests/vfio/lib/drivers/igb/igb.c
@@ -576,6 +576,7 @@ static void igb_send_msi(struct vfio_pci_device *device)
 
 const struct vfio_pci_driver_ops igb_ops = {
 	.name = "igb",
+	.region_size = sizeof(struct igb),
 	.probe = igb_probe,
 	.init = igb_init,
 	.remove = igb_remove,
diff --git a/tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c b/tools/testing/selftests/vfio/lib/drivers/ioat/ioat.c
index a871b935542b..c9b28365c5eb 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/drivers/nv_falcon/nv_falcon.c b/tools/testing/selftests/vfio/lib/drivers/nv_falcon/nv_falcon.c
index c08aa81c44f4..6958877ad463 100644
--- a/tools/testing/selftests/vfio/lib/drivers/nv_falcon/nv_falcon.c
+++ b/tools/testing/selftests/vfio/lib/drivers/nv_falcon/nv_falcon.c
@@ -775,6 +775,7 @@ static int nv_falcon_memcpy_wait(struct vfio_pci_device *device)
 
 const struct vfio_pci_driver_ops nv_falcon_ops = {
 	.name = "nv_falcon",
+	.region_size = sizeof(struct gpu_device),
 	.probe = nv_falcon_probe,
 	.init = nv_falcon_init,
 	.remove = nv_falcon_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 e5ada209b1d1..547369c5cff9 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/lib/iova_allocator.c b/tools/testing/selftests/vfio/lib/iova_allocator.c
index 4a660f636f49..a8e5815a1b16 100644
--- a/tools/testing/selftests/vfio/lib/iova_allocator.c
+++ b/tools/testing/selftests/vfio/lib/iova_allocator.c
@@ -13,8 +13,10 @@
 
 #include <linux/iommufd.h>
 #include <linux/limits.h>
+#include <linux/log2.h>
 #include <linux/mman.h>
 #include <linux/overflow.h>
+#include <linux/sizes.h>
 #include <linux/types.h>
 #include <linux/vfio.h>
 
@@ -50,7 +52,10 @@ void iova_allocator_cleanup(struct iova_allocator *allocator)
 iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size)
 {
 	VFIO_ASSERT_GT(size, 0, "Invalid size arg, zero\n");
-	VFIO_ASSERT_EQ(size & (size - 1), 0, "Invalid size arg, non-power-of-2\n");
+
+	VFIO_ASSERT_LE(size, rounddown_pow_of_two(SIZE_MAX),
+		       "Invalid size arg, too large (%zu)\n", size);
+	size = roundup_pow_of_two(size);
 
 	for (;;) {
 		struct iommu_iova_range *range;
diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_driver.c b/tools/testing/selftests/vfio/lib/vfio_pci_driver.c
index 5e65434d2318..64135ac43877 100644
--- a/tools/testing/selftests/vfio/lib/vfio_pci_driver.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_driver.c
@@ -32,6 +32,10 @@ void vfio_pci_driver_probe(struct vfio_pci_device *device)
 			continue;
 
 		device->driver.ops = ops;
+
+		VFIO_ASSERT_NE(ops->region_size, 0);
+		device->driver.region.size =
+			round_up(ops->region_size, getpagesize());
 	}
 }
 
diff --git a/tools/testing/selftests/vfio/vfio_pci_driver_test.c b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
index 761bf117d624..2bd949aafd73 100644
--- a/tools/testing/selftests/vfio/vfio_pci_driver_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
@@ -87,7 +87,8 @@ 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);
+	region_setup(self->iommu, self->iova_allocator, &driver->region,
+		     driver->region.size);
 
 	/* Any IOVA that doesn't overlap memcpy_region and driver->region. */
 	self->unmapped_iova = iova_allocator_alloc(self->iova_allocator, SZ_1G);