vfio/iommufd: Implement VFIOIOMMUClass::query_dirty_bitmap support

ioctl(iommufd, IOMMU_HWPT_GET_DIRTY_BITMAP, arg) is the UAPI
that fetches the bitmap that tells what was dirty in an IOVA
range.

A single bitmap is allocated and used across all the hwpts
sharing an IOAS which is then used in log_sync() to set Qemu
global bitmaps.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

backends/iommufd.c

@@ -261,6 +261,35 @@ bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be,
     return true;
 }
 
+bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be,
+                                      uint32_t hwpt_id,
+                                      uint64_t iova, ram_addr_t size,
+                                      uint64_t page_size, uint64_t *data,
+                                      Error **errp)
+{
+    int ret;
+    struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap = {
+        .size = sizeof(get_dirty_bitmap),
+        .hwpt_id = hwpt_id,
+        .iova = iova,
+        .length = size,
+        .page_size = page_size,
+        .data = (uintptr_t)data,
+    };
+
+    ret = ioctl(be->fd, IOMMU_HWPT_GET_DIRTY_BITMAP, &get_dirty_bitmap);
+    trace_iommufd_backend_get_dirty_bitmap(be->fd, hwpt_id, iova, size,
+                                           page_size, ret ? errno : 0);
+    if (ret) {
+        error_setg_errno(errp, errno,
+                         "IOMMU_HWPT_GET_DIRTY_BITMAP (iova: 0x%"HWADDR_PRIx
+                         " size: 0x"RAM_ADDR_FMT") failed", iova, size);
+        return false;
+    }
+
+    return true;
+}
+
 bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
                                      uint32_t *type, void *data, uint32_t len,
                                      uint64_t *caps, Error **errp)

backends/trace-events

@@ -17,3 +17,4 @@ iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas) " iommufd=%d ioas=%d"
 iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, uint32_t pt_id, uint32_t flags, uint32_t hwpt_type, uint32_t len, uint64_t data_ptr, uint32_t out_hwpt_id, int ret) " iommufd=%d dev_id=%u pt_id=%u flags=0x%x hwpt_type=%u len=%u data_ptr=0x%"PRIx64" out_hwpt=%u (%d)"
 iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d id=%d (%d)"
 iommufd_backend_set_dirty(int iommufd, uint32_t hwpt_id, bool start, int ret) " iommufd=%d hwpt=%u enable=%d (%d)"
+iommufd_backend_get_dirty_bitmap(int iommufd, uint32_t hwpt_id, uint64_t iova, uint64_t size, uint64_t page_size, int ret) " iommufd=%d hwpt=%u iova=0x%"PRIx64" size=0x%"PRIx64" page_size=0x%"PRIx64" (%d)"

hw/vfio/iommufd.c

@@ -25,6 +25,7 @@
 #include "qemu/cutils.h"
 #include "qemu/chardev_open.h"
 #include "pci.h"
+#include "exec/ram_addr.h"
 
 static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,
                             ram_addr_t size, void *vaddr, bool readonly)
@@ -146,6 +147,32 @@ err:
     return -EINVAL;
 }
 
+static int iommufd_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
+                                      VFIOBitmap *vbmap, hwaddr iova,
+                                      hwaddr size, Error **errp)
+{
+    VFIOIOMMUFDContainer *container = container_of(bcontainer,
+                                                   VFIOIOMMUFDContainer,
+                                                   bcontainer);
+    unsigned long page_size = qemu_real_host_page_size();
+    VFIOIOASHwpt *hwpt;
+
+    QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
+        if (!iommufd_hwpt_dirty_tracking(hwpt)) {
+            continue;
+        }
+
+        if (!iommufd_backend_get_dirty_bitmap(container->be, hwpt->hwpt_id,
+                                              iova, size, page_size,
+                                              (uint64_t *)vbmap->bitmap,
+                                              errp)) {
+            return -EINVAL;
+        }
+    }
+
+    return 0;
+}
+
 static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
 {
     ERRP_GUARD();
@@ -771,6 +798,7 @@ static void vfio_iommu_iommufd_class_init(ObjectClass *klass, void *data)
     vioc->detach_device = iommufd_cdev_detach;
     vioc->pci_hot_reset = iommufd_cdev_pci_hot_reset;
     vioc->set_dirty_page_tracking = iommufd_set_dirty_page_tracking;
+    vioc->query_dirty_bitmap = iommufd_query_dirty_bitmap;
 };
 
 static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,

include/sysemu/iommufd.h

@@ -57,6 +57,10 @@ bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t dev_id,
                                 Error **errp);
 bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, uint32_t hwpt_id,
                                         bool start, Error **errp);
+bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
+                                      uint64_t iova, ram_addr_t size,
+                                      uint64_t page_size, uint64_t *data,
+                                      Error **errp);
 
 #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
 #endif