vfio: selftests: Move IOVA allocator into iova_allocator.c

Move the IOVA allocator into its own file, to provide better separation
between the allocator and the struct vfio_pci_device helper code.

The allocator could go into iommu.c, but it is standalone enough that a
separate file seems cleaner. This also continues the trend of having a
.c for every major object in VFIO selftests (vfio_pci_device.c,
vfio_pci_driver.c, iommu.c, and now iova_allocator.c).

No functional change intended.

Reviewed-by: Alex Mastro <amastro@fb.com>
Tested-by: Alex Mastro <amastro@fb.com>
Reviewed-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20251126231733.3302983-13-dmatlack@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

Author: dmatlack

tools/testing/selftests/vfio/lib/iova_allocator.c

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <dirent.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/eventfd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include <uapi/linux/types.h>
+#include <linux/iommufd.h>
+#include <linux/limits.h>
+#include <linux/mman.h>
+#include <linux/overflow.h>
+#include <linux/types.h>
+#include <linux/vfio.h>
+
+#include <vfio_util.h>
+
+struct iova_allocator *iova_allocator_init(struct vfio_pci_device *device)
+{
+	struct iova_allocator *allocator;
+	struct iommu_iova_range *ranges;
+	u32 nranges;
+
+	ranges = vfio_pci_iova_ranges(device, &nranges);
+	VFIO_ASSERT_NOT_NULL(ranges);
+
+	allocator = malloc(sizeof(*allocator));
+	VFIO_ASSERT_NOT_NULL(allocator);
+
+	*allocator = (struct iova_allocator){
+		.ranges = ranges,
+		.nranges = nranges,
+		.range_idx = 0,
+		.range_offset = 0,
+	};
+
+	return allocator;
+}
+
+void iova_allocator_cleanup(struct iova_allocator *allocator)
+{
+	free(allocator->ranges);
+	free(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");
+
+	for (;;) {
+		struct iommu_iova_range *range;
+		iova_t iova, last;
+
+		VFIO_ASSERT_LT(allocator->range_idx, allocator->nranges,
+			       "IOVA allocator out of space\n");
+
+		range = &allocator->ranges[allocator->range_idx];
+		iova = range->start + allocator->range_offset;
+
+		/* Check for sufficient space at the current offset */
+		if (check_add_overflow(iova, size - 1, &last) ||
+		    last > range->last)
+			goto next_range;
+
+		/* Align iova to size */
+		iova = last & ~(size - 1);
+
+		/* Check for sufficient space at the aligned iova */
+		if (check_add_overflow(iova, size - 1, &last) ||
+		    last > range->last)
+			goto next_range;
+
+		if (last == range->last) {
+			allocator->range_idx++;
+			allocator->range_offset = 0;
+		} else {
+			allocator->range_offset = last - range->start + 1;
+		}
+
+		return iova;
+
+next_range:
+		allocator->range_idx++;
+		allocator->range_offset = 0;
+	}
+}
+

tools/testing/selftests/vfio/lib/libvfio.mk

@@ -4,6 +4,7 @@ ARCH ?= $(SUBARCH)
 LIBVFIO_SRCDIR := $(selfdir)/vfio/lib
 
 LIBVFIO_C := iommu.c
+LIBVFIO_C += iova_allocator.c
 LIBVFIO_C += vfio_pci_device.c
 LIBVFIO_C += vfio_pci_driver.c
 

tools/testing/selftests/vfio/lib/vfio_pci_device.c

@@ -24,77 +24,6 @@
 
 #define PCI_SYSFS_PATH	"/sys/bus/pci/devices"
 
-struct iova_allocator *iova_allocator_init(struct vfio_pci_device *device)
-{
-	struct iova_allocator *allocator;
-	struct iommu_iova_range *ranges;
-	u32 nranges;
-
-	ranges = vfio_pci_iova_ranges(device, &nranges);
-	VFIO_ASSERT_NOT_NULL(ranges);
-
-	allocator = malloc(sizeof(*allocator));
-	VFIO_ASSERT_NOT_NULL(allocator);
-
-	*allocator = (struct iova_allocator){
-		.ranges = ranges,
-		.nranges = nranges,
-		.range_idx = 0,
-		.range_offset = 0,
-	};
-
-	return allocator;
-}
-
-void iova_allocator_cleanup(struct iova_allocator *allocator)
-{
-	free(allocator->ranges);
-	free(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");
-
-	for (;;) {
-		struct iommu_iova_range *range;
-		iova_t iova, last;
-
-		VFIO_ASSERT_LT(allocator->range_idx, allocator->nranges,
-			       "IOVA allocator out of space\n");
-
-		range = &allocator->ranges[allocator->range_idx];
-		iova = range->start + allocator->range_offset;
-
-		/* Check for sufficient space at the current offset */
-		if (check_add_overflow(iova, size - 1, &last) ||
-		    last > range->last)
-			goto next_range;
-
-		/* Align iova to size */
-		iova = last & ~(size - 1);
-
-		/* Check for sufficient space at the aligned iova */
-		if (check_add_overflow(iova, size - 1, &last) ||
-		    last > range->last)
-			goto next_range;
-
-		if (last == range->last) {
-			allocator->range_idx++;
-			allocator->range_offset = 0;
-		} else {
-			allocator->range_offset = last - range->start + 1;
-		}
-
-		return iova;
-
-next_range:
-		allocator->range_idx++;
-		allocator->range_offset = 0;
-	}
-}
-
 static void vfio_pci_irq_set(struct vfio_pci_device *device,
 			     u32 index, u32 vector, u32 count, int *fds)
 {