RE: [PATCH v3 10/10] vfio/common: Allow disabling device dirty page tracking

[Duan, Zhenzhong]

>-----Original Message-----
>From: Joao Martins <joao.m.martins@oracle.com>
>Subject: [PATCH v3 10/10] vfio/common: Allow disabling device dirty page
>tracking
>
>The property 'x-pre-copy-dirty-page-tracking' allows disabling the whole
>tracking of VF pre-copy phase of dirty page tracking, though it means
>that it will only be used at the start of the switchover phase.
>
>Add an option that disables the VF dirty page tracking, and fall
>back into container-based dirty page tracking. This also allows to
>use IOMMU dirty tracking even on VFs with their own dirty
>tracker scheme.
>
>Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>---
> include/hw/vfio/vfio-common.h | 1 +
> hw/vfio/common.c              | 3 +++
> hw/vfio/migration.c           | 3 ++-
> hw/vfio/pci.c                 | 3 +++
> 4 files changed, 9 insertions(+), 1 deletion(-)
>
>diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-
>common.h
>index 7ce925cfab19..9db3fd31cfae 100644
>--- a/include/hw/vfio/vfio-common.h
>+++ b/include/hw/vfio/vfio-common.h
>@@ -137,6 +137,7 @@ typedef struct VFIODevice {
>     VFIOMigration *migration;
>     Error *migration_blocker;
>     OnOffAuto pre_copy_dirty_page_tracking;
>+    OnOffAuto device_dirty_page_tracking;
>     bool dirty_pages_supported;
>     bool dirty_tracking;
>     HostIOMMUDevice *hiod;
>diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>index 7cdb969fd396..eaa33d9ee037 100644
>--- a/hw/vfio/common.c
>+++ b/hw/vfio/common.c
>@@ -199,6 +199,9 @@ bool vfio_devices_all_device_dirty_tracking(const
>VFIOContainerBase *bcontainer)
>     VFIODevice *vbasedev;
>
>     QLIST_FOREACH(vbasedev, &bcontainer->device_list, container_next) {
>+        if (vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) {
>+            return false;

Maybe we can initialize vbasedev->dirty_pages_supported to false by checking 
vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF?
This way we can avoid extra check.

>+        }
>         if (!vbasedev->dirty_pages_supported) {
>             return false;
>         }
>diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
>index 89195928666f..35d67332db20 100644
>--- a/hw/vfio/migration.c
>+++ b/hw/vfio/migration.c
>@@ -1037,7 +1037,8 @@ bool vfio_migration_realize(VFIODevice
>*vbasedev, Error **errp)
>         return !vfio_block_migration(vbasedev, err, errp);
>     }
>
>-    if (!vbasedev->dirty_pages_supported &&
>+    if ((!vbasedev->dirty_pages_supported ||
>+         vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
>         (vbasedev->iommufd &&
>          !hiodc->get_cap(vbasedev->hiod,
>                          HOST_IOMMU_DEVICE_CAP_DIRTY_TRACKING, NULL))) {
>diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
>index e03d9f3ba546..22819b2036b3 100644
>--- a/hw/vfio/pci.c
>+++ b/hw/vfio/pci.c
>@@ -3362,6 +3362,9 @@ static Property vfio_pci_dev_properties[] = {
>     DEFINE_PROP_ON_OFF_AUTO("x-pre-copy-dirty-page-tracking",
>VFIOPCIDevice,
>                             vbasedev.pre_copy_dirty_page_tracking,
>                             ON_OFF_AUTO_ON),
>+    DEFINE_PROP_ON_OFF_AUTO("x-device-dirty-page-tracking",
>VFIOPCIDevice,
>+                            vbasedev.device_dirty_page_tracking,
>+                            ON_OFF_AUTO_ON),
>     DEFINE_PROP_ON_OFF_AUTO("display", VFIOPCIDevice,
>                             display, ON_OFF_AUTO_OFF),
>     DEFINE_PROP_UINT32("xres", VFIOPCIDevice, display_xres, 0),
>--
>2.17.2