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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id t15-20020a81830f000000b0060a015c9da0sm279077ywf.72.2024.03.07.23.41.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Mar 2024 23:41:08 -0800 (PST) Message-ID: Date: Fri, 8 Mar 2024 08:41:06 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 20/25] vfio: Add Error** argument to .vfio_save_config() handler Content-Language: en-US To: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= , qemu-devel@nongnu.org Cc: Peter Xu , Fabiano Rosas , Alex Williamson , Avihai Horon , =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= , Markus Armbruster , Prasad Pandit References: <20240306133441.2351700-1-clg@redhat.com> <20240306133441.2351700-21-clg@redhat.com> From: Eric Auger In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eauger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.583, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 3/7/24 14:55, Cédric Le Goater wrote: > On 3/7/24 10:13, Eric Auger wrote: >> >> >> On 3/6/24 14:34, Cédric Le Goater wrote: >>> Use vmstate_save_state_with_err() to improve error reporting in the >>> callers and store a reported error under the migration stream. Add >>> documentation while at it. >>> >>> Reviewed-by: Philippe Mathieu-Daudé >>> Signed-off-by: Cédric Le Goater >>> --- >>>   include/hw/vfio/vfio-common.h | 25 ++++++++++++++++++++++++- >>>   hw/vfio/migration.c           | 18 ++++++++++++------ >>>   hw/vfio/pci.c                 |  5 +++-- >>>   3 files changed, 39 insertions(+), 9 deletions(-) >>> >>> diff --git a/include/hw/vfio/vfio-common.h >>> b/include/hw/vfio/vfio-common.h >>> index >>> b9da6c08ef41174610eb92726c590309a53696a3..46f88493634b5634a9c14a5caa33a463fbf2c50d 100644 >>> --- a/include/hw/vfio/vfio-common.h >>> +++ b/include/hw/vfio/vfio-common.h >>> @@ -133,7 +133,30 @@ struct VFIODeviceOps { >>>       int (*vfio_hot_reset_multi)(VFIODevice *vdev); >>>       void (*vfio_eoi)(VFIODevice *vdev); >>>       Object *(*vfio_get_object)(VFIODevice *vdev); >>> -    void (*vfio_save_config)(VFIODevice *vdev, QEMUFile *f); >>> + >>> +    /** >>> +     * @vfio_save_config >>> +     * >>> +     * Save device config state >>> +     * >>> +     * @vdev: #VFIODevice for which to save the config >>> +     * @f: #QEMUFile where to send the data >>> +     * @errp: pointer to Error*, to store an error if it happens. >>> +     * >>> +     * Returns zero to indicate success and negative for error >>> +     */ >>> +    int (*vfio_save_config)(VFIODevice *vdev, QEMUFile *f, Error >>> **errp); >>> + >>> +    /** >>> +     * @vfio_load_config >>> +     * >>> +     * Load device config state >>> +     * >>> +     * @vdev: #VFIODevice for which to load the config >>> +     * @f: #QEMUFile where to get the data >>> +     * >>> +     * Returns zero to indicate success and negative for error >>> +     */ >>>       int (*vfio_load_config)(VFIODevice *vdev, QEMUFile *f); >>>   }; >>>   diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c >>> index >>> 71ade14a7942358094371a86c00718f5979113ea..bd48f2ee472a5230c2c84bff829dae1e217db33f 100644 >>> --- a/hw/vfio/migration.c >>> +++ b/hw/vfio/migration.c >>> @@ -190,14 +190,19 @@ static int vfio_load_buffer(QEMUFile *f, >>> VFIODevice *vbasedev, >>>       return ret; >>>   } >>>   -static int vfio_save_device_config_state(QEMUFile *f, void *opaque) >>> +static int vfio_save_device_config_state(QEMUFile *f, void *opaque, >>> +                                         Error **errp) >>>   { >>>       VFIODevice *vbasedev = opaque; >>> +    int ret; >>>         qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE); >>>         if (vbasedev->ops && vbasedev->ops->vfio_save_config) { >>> -        vbasedev->ops->vfio_save_config(vbasedev, f); >>> +        ret = vbasedev->ops->vfio_save_config(vbasedev, f, errp); >>> +        if (ret) { >> I am not familiar enough with that case but don't you still want to set >> the VFIO_MIG_FLAG_END_OF_STATE to "close" the state? > > This is a delimiter used on the target side when loading the state. > > When QEMU fails to capture the device state, the whole migration is marked > as in error. There is no need to end cleanly the device state, it is bogus > anyhow. OK thanks Eric > > Thanks, > > C. > > >> >> Eric >>> +            return ret; >>> +        } >>>       } >>>         qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); >>> @@ -587,13 +592,14 @@ static int vfio_save_complete_precopy(QEMUFile >>> *f, void *opaque) >>>   static void vfio_save_state(QEMUFile *f, void *opaque) >>>   { >>>       VFIODevice *vbasedev = opaque; >>> +    Error *local_err = NULL; >>>       int ret; >>>   -    ret = vfio_save_device_config_state(f, opaque); >>> +    ret = vfio_save_device_config_state(f, opaque, &local_err); >>>       if (ret) { >>> -        error_report("%s: Failed to save device config space", >>> -                     vbasedev->name); >>> -        qemu_file_set_error(f, ret); >>> +        error_prepend(&local_err, "%s: Failed to save device config >>> space", >>> +                      vbasedev->name); >>> +        qemu_file_set_error_obj(f, ret, local_err); >>>       } >>>   } >>>   diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c >>> index >>> 4fa387f0430d62ca2ba1b5ae5b7037f8f06b33f9..99d86e1d40ef25133fc76ad6e58294b07bd20843 100644 >>> --- a/hw/vfio/pci.c >>> +++ b/hw/vfio/pci.c >>> @@ -2585,11 +2585,12 @@ const VMStateDescription >>> vmstate_vfio_pci_config = { >>>       } >>>   }; >>>   -static void vfio_pci_save_config(VFIODevice *vbasedev, QEMUFile *f) >>> +static int vfio_pci_save_config(VFIODevice *vbasedev, QEMUFile *f, >>> Error **errp) >>>   { >>>       VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, >>> vbasedev); >>>   -    vmstate_save_state(f, &vmstate_vfio_pci_config, vdev, NULL); >>> +    return vmstate_save_state_with_err(f, &vmstate_vfio_pci_config, >>> vdev, NULL, >>> +                                       errp); >>>   } >>>     static int vfio_pci_load_config(VFIODevice *vbasedev, QEMUFile *f) >> >