vfio/iommufd: Probe and request hwpt dirty tracking capability

In preparation to using the dirty tracking UAPI, probe whether the IOMMU
supports dirty tracking. This is done via the data stored in
hiod::caps::hw_caps initialized from GET_HW_INFO.

Qemu doesn't know if VF dirty tracking is supported when allocating
hardware pagetable in iommufd_cdev_autodomains_get(). This is because
VFIODevice migration state hasn't been initialized *yet* hence it can't pick
between VF dirty tracking vs IOMMU dirty tracking. So, if IOMMU supports
dirty tracking it always creates HWPTs with IOMMU_HWPT_ALLOC_DIRTY_TRACKING
even if later on VFIOMigration decides to use VF dirty tracking instead.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
[ clg: - Fixed vbasedev->iommu_dirty_tracking assignment in
         iommufd_cdev_autodomains_get()
       - Added warning for heterogeneous dirty page tracking support
	 in iommufd_cdev_autodomains_get() ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>

diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 798c4798a55e0c839c5128b3cd9571356157dce9..240c476eaf5b9b79090b6767c18316ade3b3b794 100644 (file)
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -110,6 +110,11 @@ static void iommufd_cdev_unbind_and_disconnect(VFIODevice *vbasedev)
     iommufd_backend_disconnect(vbasedev->iommufd);
 }
 
+static bool iommufd_hwpt_dirty_tracking(VFIOIOASHwpt *hwpt)
+{
+    return hwpt && hwpt->hwpt_flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
+}
+
 static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
 {
     ERRP_GUARD();
@@ -243,10 +248,22 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
         } else {
             vbasedev->hwpt = hwpt;
             QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next);
+            vbasedev->iommu_dirty_tracking = iommufd_hwpt_dirty_tracking(hwpt);
             return true;
         }
     }
 
+    /*
+     * This is quite early and VFIO Migration state isn't yet fully
+     * initialized, thus rely only on IOMMU hardware capabilities as to
+     * whether IOMMU dirty tracking is going to be requested. Later
+     * vfio_migration_realize() may decide to use VF dirty tracking
+     * instead.
+     */
+    if (vbasedev->hiod->caps.hw_caps & IOMMU_HW_CAP_DIRTY_TRACKING) {
+        flags = IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
+    }
+
     if (!iommufd_backend_alloc_hwpt(iommufd, vbasedev->devid,
                                     container->ioas_id, flags,
                                     IOMMU_HWPT_DATA_NONE, 0, NULL,
@@ -256,6 +273,7 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
 
     hwpt = g_malloc0(sizeof(*hwpt));
     hwpt->hwpt_id = hwpt_id;
+    hwpt->hwpt_flags = flags;
     QLIST_INIT(&hwpt->device_list);
 
     ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id, errp);
@@ -266,8 +284,16 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
     }
 
     vbasedev->hwpt = hwpt;
+    vbasedev->iommu_dirty_tracking = iommufd_hwpt_dirty_tracking(hwpt);
     QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next);
     QLIST_INSERT_HEAD(&container->hwpt_list, hwpt, next);
+    container->bcontainer.dirty_pages_supported |=
+                                vbasedev->iommu_dirty_tracking;
+    if (container->bcontainer.dirty_pages_supported &&
+        !vbasedev->iommu_dirty_tracking) {
+        warn_report("IOMMU instance for device %s doesn't support dirty tracking",
+                    vbasedev->name);
+    }
     return true;
 }
 

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 4e44b26d3c453b5b47a819df371a21a4ca3b39c3..1e02c98b09babb6878fed1130cd1d6a00ac3641e 100644 (file)
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -97,6 +97,7 @@ typedef struct IOMMUFDBackend IOMMUFDBackend;
 
 typedef struct VFIOIOASHwpt {
     uint32_t hwpt_id;
+    uint32_t hwpt_flags;
     QLIST_HEAD(, VFIODevice) device_list;
     QLIST_ENTRY(VFIOIOASHwpt) next;
 } VFIOIOASHwpt;
@@ -139,6 +140,7 @@ typedef struct VFIODevice {
     OnOffAuto pre_copy_dirty_page_tracking;
     bool dirty_pages_supported;
     bool dirty_tracking;
+    bool iommu_dirty_tracking;
     HostIOMMUDevice *hiod;
     int devid;
     IOMMUFDBackend *iommufd;