[PATCH RFCv2 5/8] vfio/iommufd: Implement VFIOIOMMUClass::query_dirty_bitmap support

[Joao Martins]

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>
---
 backends/iommufd.c       | 24 ++++++++++++++++++++++++
 backends/trace-events    |  1 +
 hw/vfio/iommufd.c        | 30 ++++++++++++++++++++++++++++++
 include/sysemu/iommufd.h |  3 +++
 4 files changed, 58 insertions(+)

diff --git a/backends/iommufd.c b/backends/iommufd.c
index 954de61c2da0..dd676d493c37 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -259,6 +259,30 @@ int iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, 
uint32_t hwpt_id,
     return !ret ? 0 : -errno;
 }
 
+int 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)
+{
+    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);
+    if (ret) {
+        error_report("IOMMU_HWPT_GET_DIRTY_BITMAP (iova: 0x%"PRIx64
+                     " size: 0x%"PRIx64") failed: %s", iova,
+                     size, strerror(errno));
+    }
+
+    return !ret ? 0 : -errno;
+}
+
 static const TypeInfo iommufd_backend_info = {
     .name = TYPE_IOMMUFD_BACKEND,
     .parent = TYPE_OBJECT,
diff --git a/backends/trace-events b/backends/trace-events
index feba2baca5f7..11a27cb114b6 100644
--- a/backends/trace-events
+++ b/backends/trace-events
@@ -17,3 +17,4 @@ iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, 
uint32_t pt_id, uint32_
 iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas, int ret) " iommufd=%d 
ioas=%d (%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=%d 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=%d 
iova=0x%"PRIx64" size=0x%"PRIx64" page_size=0x%"PRIx64" (%d)"
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 361e659288fd..79b13bd262cc 100644
--- a/hw/vfio/iommufd.c
+++ b/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"
 #include "migration/migration.h"
 
 static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,
@@ -142,6 +143,34 @@ err:
     return ret;
 }
 
+static int iommufd_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
+                                      VFIOBitmap *vbmap, uint64_t iova,
+                                      uint64_t size)
+{
+    VFIOIOMMUFDContainer *container = container_of(bcontainer,
+                                                   VFIOIOMMUFDContainer,
+                                                   bcontainer);
+    int ret;
+    VFIOIOASHwpt *hwpt;
+    unsigned long page_size;
+
+    if (!bcontainer->dirty_pages_supported) {
+        return 0;
+    }
+
+    page_size = qemu_real_host_page_size();
+    QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
+        ret = iommufd_backend_get_dirty_bitmap(container->be, hwpt->hwpt_id,
+                                               iova, size, page_size,
+                                               vbmap->bitmap);
+        if (ret) {
+            break;
+        }
+    }
+
+    return ret;
+}
+
 static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
 {
     long int ret = -ENOTTY;
@@ -765,6 +794,7 @@ static void vfio_iommu_iommufd_class_init(ObjectClass 
*klass, void *data)
     vioc->pci_hot_reset = iommufd_cdev_pci_hot_reset;
     vioc->host_iommu_device_init = vfio_cdev_host_iommu_device_init;
     vioc->set_dirty_page_tracking = iommufd_set_dirty_page_tracking;
+    vioc->query_dirty_bitmap = iommufd_query_dirty_bitmap;
 };
 
 static const TypeInfo types[] = {
diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
index 562c189dd92c..ba19b7ea4c19 100644
--- a/include/sysemu/iommufd.h
+++ b/include/sysemu/iommufd.h
@@ -55,5 +55,8 @@ int iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id,
                                void *data_ptr, uint32_t *out_hwpt);
 int iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, uint32_t hwpt_id,
                                        bool start);
+int 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);
 
 #endif
-- 
2.39.3