[PATCH v2 07/20] vfio/common: Add VFIOBitmap and (de)alloc functions

[Avihai Horon]

There are already two places where dirty page bitmap allocation and
calculations are done in open code. With device dirty page tracking
being added in next patches, there are going to be even more places.

To avoid code duplication, introduce VFIOBitmap struct and corresponding
alloc and dealloc functions and use them where applicable.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
---
 hw/vfio/common.c | 89 ++++++++++++++++++++++++++++++++----------------
 1 file changed, 60 insertions(+), 29 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index ac93b85632..84f08bdbbb 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -320,6 +320,41 @@ const MemoryRegionOps vfio_region_ops = {
  * Device state interfaces
  */
 
+typedef struct {
+    unsigned long *bitmap;
+    hwaddr size;
+    hwaddr pages;
+} VFIOBitmap;
+
+static VFIOBitmap *vfio_bitmap_alloc(hwaddr size)
+{
+    VFIOBitmap *vbmap = g_try_new0(VFIOBitmap, 1);
+    if (!vbmap) {
+        errno = ENOMEM;
+
+        return NULL;
+    }
+
+    vbmap->pages = REAL_HOST_PAGE_ALIGN(size) / qemu_real_host_page_size();
+    vbmap->size = ROUND_UP(vbmap->pages, sizeof(__u64) * BITS_PER_BYTE) /
+                                         BITS_PER_BYTE;
+    vbmap->bitmap = g_try_malloc0(vbmap->size);
+    if (!vbmap->bitmap) {
+        g_free(vbmap);
+        errno = ENOMEM;
+
+        return NULL;
+    }
+
+    return vbmap;
+}
+
+static void vfio_bitmap_dealloc(VFIOBitmap *vbmap)
+{
+    g_free(vbmap->bitmap);
+    g_free(vbmap);
+}
+
 bool vfio_mig_active(void)
 {
     VFIOGroup *group;
@@ -470,9 +505,14 @@ static int vfio_dma_unmap_bitmap(VFIOContainer *container,
 {
     struct vfio_iommu_type1_dma_unmap *unmap;
     struct vfio_bitmap *bitmap;
-    uint64_t pages = REAL_HOST_PAGE_ALIGN(size) / qemu_real_host_page_size();
+    VFIOBitmap *vbmap;
     int ret;
 
+    vbmap = vfio_bitmap_alloc(size);
+    if (!vbmap) {
+        return -errno;
+    }
+
     unmap = g_malloc0(sizeof(*unmap) + sizeof(*bitmap));
 
     unmap->argsz = sizeof(*unmap) + sizeof(*bitmap);
@@ -486,35 +526,28 @@ static int vfio_dma_unmap_bitmap(VFIOContainer *container,
      * qemu_real_host_page_size to mark those dirty. Hence set bitmap_pgsize
      * to qemu_real_host_page_size.
      */
-
     bitmap->pgsize = qemu_real_host_page_size();
-    bitmap->size = ROUND_UP(pages, sizeof(__u64) * BITS_PER_BYTE) /
-                   BITS_PER_BYTE;
+    bitmap->size = vbmap->size;
+    bitmap->data = (__u64 *)vbmap->bitmap;
 
-    if (bitmap->size > container->max_dirty_bitmap_size) {
-        error_report("UNMAP: Size of bitmap too big 0x%"PRIx64,
-                     (uint64_t)bitmap->size);
+    if (vbmap->size > container->max_dirty_bitmap_size) {
+        error_report("UNMAP: Size of bitmap too big 0x%"PRIx64, vbmap->size);
         ret = -E2BIG;
         goto unmap_exit;
     }
 
-    bitmap->data = g_try_malloc0(bitmap->size);
-    if (!bitmap->data) {
-        ret = -ENOMEM;
-        goto unmap_exit;
-    }
-
     ret = ioctl(container->fd, VFIO_IOMMU_UNMAP_DMA, unmap);
     if (!ret) {
-        cpu_physical_memory_set_dirty_lebitmap((unsigned long *)bitmap->data,
-                iotlb->translated_addr, pages);
+        cpu_physical_memory_set_dirty_lebitmap(vbmap->bitmap,
+                iotlb->translated_addr, vbmap->pages);
     } else {
         error_report("VFIO_UNMAP_DMA with DIRTY_BITMAP : %m");
     }
 
-    g_free(bitmap->data);
 unmap_exit:
     g_free(unmap);
+    vfio_bitmap_dealloc(vbmap);
+
     return ret;
 }
 
@@ -1331,7 +1364,7 @@ static int vfio_get_dirty_bitmap(VFIOContainer 
*container, uint64_t iova,
 {
     struct vfio_iommu_type1_dirty_bitmap *dbitmap;
     struct vfio_iommu_type1_dirty_bitmap_get *range;
-    uint64_t pages;
+    VFIOBitmap *vbmap;
     int ret;
 
     if (!container->dirty_pages_supported) {
@@ -1341,6 +1374,11 @@ static int vfio_get_dirty_bitmap(VFIOContainer 
*container, uint64_t iova,
         return 0;
     }
 
+    vbmap = vfio_bitmap_alloc(size);
+    if (!vbmap) {
+        return -errno;
+    }
+
     dbitmap = g_malloc0(sizeof(*dbitmap) + sizeof(*range));
 
     dbitmap->argsz = sizeof(*dbitmap) + sizeof(*range);
@@ -1355,15 +1393,8 @@ static int vfio_get_dirty_bitmap(VFIOContainer 
*container, uint64_t iova,
      * to qemu_real_host_page_size.
      */
     range->bitmap.pgsize = qemu_real_host_page_size();
-
-    pages = REAL_HOST_PAGE_ALIGN(range->size) / qemu_real_host_page_size();
-    range->bitmap.size = ROUND_UP(pages, sizeof(__u64) * BITS_PER_BYTE) /
-                                         BITS_PER_BYTE;
-    range->bitmap.data = g_try_malloc0(range->bitmap.size);
-    if (!range->bitmap.data) {
-        ret = -ENOMEM;
-        goto err_out;
-    }
+    range->bitmap.size = vbmap->size;
+    range->bitmap.data = (__u64 *)vbmap->bitmap;
 
     ret = ioctl(container->fd, VFIO_IOMMU_DIRTY_PAGES, dbitmap);
     if (ret) {
@@ -1374,14 +1405,14 @@ static int vfio_get_dirty_bitmap(VFIOContainer 
*container, uint64_t iova,
         goto err_out;
     }
 
-    cpu_physical_memory_set_dirty_lebitmap((unsigned long *)range->bitmap.data,
-                                            ram_addr, pages);
+    cpu_physical_memory_set_dirty_lebitmap(vbmap->bitmap, ram_addr,
+                                           vbmap->pages);
 
     trace_vfio_get_dirty_bitmap(container->fd, range->iova, range->size,
                                 range->bitmap.size, ram_addr);
 err_out:
-    g_free(range->bitmap.data);
     g_free(dbitmap);
+    vfio_bitmap_dealloc(vbmap);
 
     return ret;
 }
-- 
2.26.3