Re: [PATCH V1 23/26] vfio/iommufd: register container for cpr

["Cédric Le Goater" <clg@redhat.com>]

On 1/29/25 15:43, Steve Sistare wrote:
> Register a vfio iommufd container for CPR.  Add a blocker if the kernel does
> not support IOMMU_IOAS_CHANGE_PROCESS.
> 
> This is mostly boiler plate.  The fields to to saved and restored are added
> in subsequent patches.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>   hw/vfio/cpr-iommufd.c         | 96 +++++++++++++++++++++++++++++++++++++++++++
>   hw/vfio/iommufd.c             | 12 +++---
>   hw/vfio/meson.build           |  1 +
>   include/hw/vfio/vfio-common.h |  6 +++
>   4 files changed, 110 insertions(+), 5 deletions(-)
>   create mode 100644 hw/vfio/cpr-iommufd.c
> 
> diff --git a/hw/vfio/cpr-iommufd.c b/hw/vfio/cpr-iommufd.c
> new file mode 100644
> index 0000000..4eb358a
> --- /dev/null
> +++ b/hw/vfio/cpr-iommufd.c
> @@ -0,0 +1,96 @@
> +/*
> + * Copyright (c) 2024-2025 Oracle and/or its affiliates.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "hw/vfio/vfio-common.h"
> +#include "migration/blocker.h"
> +#include "migration/cpr.h"
> +#include "migration/migration.h"
> +#include "migration/vmstate.h"
> +#include "system/iommufd.h"
> +
> +static bool vfio_cpr_supported(VFIOIOMMUFDContainer *container, Error **errp)
> +{
> +    if (!iommufd_change_process_capable(container->be)) {
> +        error_setg(errp,
> +                   "VFIO container does not support IOMMU_IOAS_CHANGE_PROCESS");
> +        return false;
> +    }
> +    return true;
> +}
> +
> +static const VMStateDescription vfio_container_vmstate = {
> +    .name = "vfio-iommufd-container",
> +    .version_id = 0,
> +    .minimum_version_id = 0,
> +    .needed = cpr_needed_for_reuse,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static const VMStateDescription iommufd_cpr_vmstate = {
> +    .name = "iommufd",
> +    .version_id = 0,
> +    .minimum_version_id = 0,
> +    .needed = cpr_needed_for_reuse,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +bool vfio_iommufd_cpr_register_container(VFIOIOMMUFDContainer *container,
> +                                         Error **errp)
> +{
> +    VFIOContainerBase *bcontainer = &container->bcontainer;
> +    Error **cpr_blocker = &container->cpr_blocker;
> +
> +    if (!vfio_cpr_register_container(bcontainer, errp)) {
> +        return false;
> +    }
> +
> +    if (!vfio_cpr_supported(container, cpr_blocker)) {
> +        return migrate_add_blocker_modes(cpr_blocker, errp,
> +                                         MIG_MODE_CPR_TRANSFER, -1) == 0;
> +    }
> +
> +    vmstate_register(NULL, -1, &vfio_container_vmstate, container);
> +    vmstate_register(NULL, -1, &iommufd_cpr_vmstate, container->be);
> +
> +    return true;
> +}
> +
> +void vfio_iommufd_cpr_unregister_container(VFIOIOMMUFDContainer *container)
> +{
> +    VFIOContainerBase *bcontainer = &container->bcontainer;
> +
> +    vmstate_unregister(NULL, &iommufd_cpr_vmstate, container->be);
> +    vmstate_unregister(NULL, &vfio_container_vmstate, container);
> +    migrate_del_blocker(&container->cpr_blocker);
> +    vfio_cpr_unregister_container(bcontainer);
> +}
> +
> +static const VMStateDescription vfio_device_vmstate = {
> +    .name = "vfio-iommufd-device",
> +    .version_id = 0,
> +    .minimum_version_id = 0,
> +    .needed = cpr_needed_for_reuse,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +void vfio_iommufd_cpr_register_device(VFIODevice *vbasedev)
> +{
> +    vmstate_register(NULL, -1, &vfio_device_vmstate, vbasedev);
> +}
> +
> +void vfio_iommufd_cpr_unregister_device(VFIODevice *vbasedev)
> +{
> +    vmstate_unregister(NULL, &vfio_device_vmstate, vbasedev);
> +}
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index 8308715..ae78e00 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -592,6 +592,10 @@ static bool iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,
>   
>       bcontainer->initialized = true;
>   
> +    if (!vfio_iommufd_cpr_register_container(container, errp)) {
> +        goto err_listener_register;
> +    }
> +

why this change ?


Thanks,

C.



>   found_container:
>       ret = ioctl(devfd, VFIO_DEVICE_GET_INFO, &dev_info);
>       if (ret) {
> @@ -599,10 +603,6 @@ found_container:
>           goto err_listener_register;
>       }
>   
> -    if (!vfio_cpr_register_container(bcontainer, errp)) {
> -        goto err_listener_register;
> -    }
> -
>       /*
>        * TODO: examine RAM_BLOCK_DISCARD stuff, should we do group level
>        * for discarding incompatibility check as well?
> @@ -619,6 +619,7 @@ found_container:
>       vbasedev->bcontainer = bcontainer;
>       QLIST_INSERT_HEAD(&bcontainer->device_list, vbasedev, container_next);
>       QLIST_INSERT_HEAD(&vfio_device_list, vbasedev, global_next);
> +    vfio_iommufd_cpr_register_device(vbasedev);
>   
>       trace_iommufd_cdev_device_info(vbasedev->name, devfd, vbasedev->num_irqs,
>                                      vbasedev->num_regions, vbasedev->flags);
> @@ -653,12 +654,13 @@ static void iommufd_cdev_detach(VFIODevice *vbasedev)
>           iommufd_cdev_ram_block_discard_disable(false);
>       }
>   
> -    vfio_cpr_unregister_container(bcontainer);
> +    vfio_iommufd_cpr_unregister_container(container);
>       iommufd_cdev_detach_container(vbasedev, container);
>       iommufd_cdev_container_destroy(container);
>       vfio_put_address_space(space);
>   
>       migrate_del_blocker(&vbasedev->cpr_id_blocker);
> +    vfio_iommufd_cpr_unregister_device(vbasedev);
>       iommufd_cdev_unbind_and_disconnect(vbasedev);
>       close(vbasedev->fd);
>   }
> diff --git a/hw/vfio/meson.build b/hw/vfio/meson.build
> index 5487815..998adb5 100644
> --- a/hw/vfio/meson.build
> +++ b/hw/vfio/meson.build
> @@ -13,6 +13,7 @@ vfio_ss.add(when: 'CONFIG_IOMMUFD', if_true: files(
>   vfio_ss.add(when: 'CONFIG_VFIO_PCI', if_true: files(
>     'cpr.c',
>     'cpr-legacy.c',
> +  'cpr-iommufd.c',
>     'display.c',
>     'pci-quirks.c',
>     'pci.c',
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 37e7c26..add44d4 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -113,6 +113,7 @@ typedef struct VFIOIOASHwpt {
>   typedef struct VFIOIOMMUFDContainer {
>       VFIOContainerBase bcontainer;
>       IOMMUFDBackend *be;
> +    Error *cpr_blocker;
>       uint32_t ioas_id;
>       QLIST_HEAD(, VFIOIOASHwpt) hwpt_list;
>   } VFIOIOMMUFDContainer;
> @@ -271,6 +272,11 @@ bool vfio_legacy_cpr_register_container(VFIOContainer *container, Error **errp);
>   void vfio_legacy_cpr_unregister_container(VFIOContainer *container);
>   bool iommufd_cdev_get_info_iova_range(VFIOIOMMUFDContainer *container,
>                                         uint32_t ioas_id, Error **errp);
> +bool vfio_iommufd_cpr_register_container(VFIOIOMMUFDContainer *container,
> +                                         Error **errp);
> +void vfio_iommufd_cpr_unregister_container(VFIOIOMMUFDContainer *container);
> +void vfio_iommufd_cpr_register_device(VFIODevice *vbasedev);
> +void vfio_iommufd_cpr_unregister_device(VFIODevice *vbasedev);
>   
>   extern const MemoryRegionOps vfio_region_ops;
>   typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;