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x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 25 Jan 2024 16:10:30 +0800 Longfang Liu wrote: > On the debugfs framework of VFIO, if the CONFIG_VFIO_DEBUGFS macro is > enabled, the debug function is registered for the live migration driver > of the HiSilicon accelerator device. > > After registering the HiSilicon accelerator device on the debugfs > framework of live migration of vfio, a directory file "hisi_acc" > of debugfs is created, and then three debug function files are > created in this directory: > > vfio > | > +--- > | +---migration > | +--state > | +--hisi_acc > | +--attr > | +--data > | +--save > | +--cmd_state > | > +--- > +---migration > +--state > +--hisi_acc > +--attr > +--data > +--save > +--cmd_state > > data file: used to get the migration data from the driver > attr file: used to get device attributes parameters from the driver > save file: used to read the data of the live migration device and save > it to the driver. > cmd_state: used to get the cmd channel state for the device. > > Signed-off-by: Longfang Liu > --- > .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 190 ++++++++++++++++++ > .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 5 + > 2 files changed, 195 insertions(+) > > diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c > index 5f6e01571a7b..2cbbc52b7377 100644 > --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c > +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c > @@ -15,6 +15,7 @@ > #include > > #include "hisi_acc_vfio_pci.h" > +#include "../../vfio.h" > > /* Return 0 on VM acc device ready, -ETIMEDOUT hardware timeout */ > static int qm_wait_dev_not_ready(struct hisi_qm *qm) > @@ -617,6 +618,18 @@ hisi_acc_check_int_state(struct hisi_acc_vf_core_device *hisi_acc_vdev) > } > } > > +static void hisi_acc_vf_migf_save(struct hisi_acc_vf_migration_file *dst_migf, > + struct hisi_acc_vf_migration_file *src_migf) > +{ > + if (!dst_migf) > + return; > + > + dst_migf->disabled = false; > + dst_migf->total_length = src_migf->total_length; > + memcpy(&dst_migf->vf_data, &src_migf->vf_data, > + sizeof(struct acc_vf_data)); > +} > + > static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf) > { > mutex_lock(&migf->lock); > @@ -629,12 +642,16 @@ static void hisi_acc_vf_disable_fd(struct hisi_acc_vf_migration_file *migf) > static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vdev) > { > if (hisi_acc_vdev->resuming_migf) { > + hisi_acc_vf_migf_save(hisi_acc_vdev->debug_migf, > + hisi_acc_vdev->resuming_migf); > hisi_acc_vf_disable_fd(hisi_acc_vdev->resuming_migf); > fput(hisi_acc_vdev->resuming_migf->filp); > hisi_acc_vdev->resuming_migf = NULL; > } > > if (hisi_acc_vdev->saving_migf) { > + hisi_acc_vf_migf_save(hisi_acc_vdev->debug_migf, > + hisi_acc_vdev->saving_migf); > hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf); > fput(hisi_acc_vdev->saving_migf->filp); > hisi_acc_vdev->saving_migf = NULL; > @@ -1175,6 +1192,7 @@ static int hisi_acc_vf_qm_init(struct hisi_acc_vf_core_device *hisi_acc_vdev) > if (!vf_qm->io_base) > return -EIO; > > + mutex_init(&hisi_acc_vdev->enable_mutex); > vf_qm->fun_type = QM_HW_VF; > vf_qm->pdev = vf_dev; > mutex_init(&vf_qm->mailbox_lock); > @@ -1325,6 +1343,172 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int > return vfio_pci_core_ioctl(core_vdev, cmd, arg); > } > > +static int hisi_acc_vf_debug_check(struct seq_file *seq, struct vfio_device *vdev) > +{ > + struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev); > + struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf; > + > + if (!vdev->mig_ops || !migf) { > + seq_printf(seq, "%s\n", "device does not support live migration!"); > + return -EINVAL; > + } > + > + /** > + * When the device is not opened, the io_base is not mapped. > + * The driver cannot perform device read and write operations. > + */ > + if (!vdev->open_count) { > + seq_printf(seq, "%s\n", "device not opened!"); > + return -EINVAL; > + } This is racy, this check could occur while the user is already closing the device and vfio_df_device_last_close() may have already iounmap'd the io_base. Only after that is open_count decremented. The debugfs interfaces would then proceed to access the unmapped space. The enable_mutex is entirely ineffective (and also asymmetric, initialized in the open_device path but never destroyed). In fact, the enable_mutex really only seems to be trying to protect io_base (which it doesn't do), meanwhile the core driver execution path can run concurrently to debugfs operations with no serialization. It looks like these operations would step on each other. I think you might need an atomic to guard against io_base unmapping and then maybe a mutex or semaphore to avoid debugfs accesses from interfering with the actual core logic interacting with the device. Thanks, Alex > + > + return 0; > +} > + > +static int hisi_acc_vf_debug_cmd(struct seq_file *seq, void *data) > +{ > + struct device *vf_dev = seq->private; > + struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev); > + struct vfio_device *vdev = &core_device->vdev; > + struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev); > + struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm; > + u64 value; > + int ret; > + > + ret = hisi_acc_vf_debug_check(seq, vdev); > + if (ret) > + return 0; > + > + mutex_lock(&hisi_acc_vdev->enable_mutex); > + ret = qm_wait_dev_not_ready(vf_qm); > + if (ret) { > + mutex_unlock(&hisi_acc_vdev->enable_mutex); > + seq_printf(seq, "%s\n", "VF device not ready!"); > + return 0; > + } > + > + value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE); > + mutex_unlock(&hisi_acc_vdev->enable_mutex); > + seq_printf(seq, "%s:0x%llx\n", "mailbox cmd channel state is OK", value); > + > + return 0; > +} > + > +static int hisi_acc_vf_debug_save(struct seq_file *seq, void *data) > +{ > + struct device *vf_dev = seq->private; > + struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev); > + struct vfio_device *vdev = &core_device->vdev; > + struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev); > + struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev->debug_migf; > + int ret; > + > + ret = hisi_acc_vf_debug_check(seq, vdev); > + if (ret) > + return 0; > + > + mutex_lock(&hisi_acc_vdev->enable_mutex); > + ret = vf_qm_state_save(hisi_acc_vdev, migf); > + if (ret) { > + mutex_unlock(&hisi_acc_vdev->enable_mutex); > + seq_printf(seq, "%s\n", "failed to save device data!"); > + return 0; > + } > + mutex_unlock(&hisi_acc_vdev->enable_mutex); > + seq_printf(seq, "%s\n", "successful to save device data!"); > + > + return 0; > +} > + > +static int hisi_acc_vf_data_read(struct seq_file *seq, void *data) > +{ > + struct device *vf_dev = seq->private; > + struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev); > + struct vfio_device *vdev = &core_device->vdev; > + struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev); > + struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf; > + size_t vf_data_sz = offsetofend(struct acc_vf_data, padding); > + > + if (debug_migf && debug_migf->total_length) > + seq_hex_dump(seq, "Mig Data:", DUMP_PREFIX_OFFSET, 16, 1, > + (unsigned char *)&debug_migf->vf_data, > + vf_data_sz, false); > + else > + seq_printf(seq, "%s\n", "device not migrated!"); > + > + return 0; > +} > + > +static int hisi_acc_vf_attr_read(struct seq_file *seq, void *data) > +{ > + struct device *vf_dev = seq->private; > + struct vfio_pci_core_device *core_device = dev_get_drvdata(vf_dev); > + struct vfio_device *vdev = &core_device->vdev; > + struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev); > + struct hisi_acc_vf_migration_file *debug_migf = hisi_acc_vdev->debug_migf; > + > + if (debug_migf && debug_migf->total_length) { > + seq_printf(seq, > + "acc device:\n" > + "device state: %d\n" > + "device ready: %u\n" > + "data valid: %d\n" > + "data size: %lu\n", > + hisi_acc_vdev->mig_state, > + hisi_acc_vdev->vf_qm_state, > + debug_migf->disabled, > + debug_migf->total_length); > + } else { > + seq_printf(seq, "%s\n", "device not migrated!"); > + } > + > + return 0; > +} > + > +static int hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vdev) > +{ > + struct vfio_device *vdev = &hisi_acc_vdev->core_device.vdev; > + struct dentry *vfio_dev_migration = NULL; > + struct dentry *vfio_hisi_acc = NULL; > + struct device *dev = vdev->dev; > + void *migf = NULL; > + > + if (!debugfs_initialized()) > + return 0; > + > + migf = kzalloc(sizeof(struct hisi_acc_vf_migration_file), GFP_KERNEL); > + if (!migf) > + return -ENOMEM; > + hisi_acc_vdev->debug_migf = migf; > + > + vfio_dev_migration = debugfs_lookup("migration", vdev->debug_root); > + if (!vfio_dev_migration) { > + kfree(migf); > + dev_err(dev, "failed to lookup migration debugfs file!\n"); > + return -ENODEV; > + } > + > + vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration); > + debugfs_create_devm_seqfile(dev, "data", vfio_hisi_acc, > + hisi_acc_vf_data_read); > + debugfs_create_devm_seqfile(dev, "attr", vfio_hisi_acc, > + hisi_acc_vf_attr_read); > + debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc, > + hisi_acc_vf_debug_cmd); > + debugfs_create_devm_seqfile(dev, "save", vfio_hisi_acc, > + hisi_acc_vf_debug_save); > + > + return 0; > +} > + > +static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev) > +{ > + if (!debugfs_initialized()) > + return; > + > + kfree(hisi_acc_vdev->debug_migf); > +} > + > static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev) > { > struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev); > @@ -1353,7 +1537,9 @@ static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev) > struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev); > struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm; > > + mutex_lock(&hisi_acc_vdev->enable_mutex); > iounmap(vf_qm->io_base); > + mutex_unlock(&hisi_acc_vdev->enable_mutex); > vfio_pci_core_close_device(core_vdev); > } > > @@ -1444,6 +1630,9 @@ static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device > ret = vfio_pci_core_register_device(&hisi_acc_vdev->core_device); > if (ret) > goto out_put_vdev; > + > + if (ops == &hisi_acc_vfio_pci_migrn_ops) > + hisi_acc_vfio_debug_init(hisi_acc_vdev); > return 0; > > out_put_vdev: > @@ -1456,6 +1645,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev) > struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev); > > vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device); > + hisi_acc_vf_debugfs_exit(hisi_acc_vdev); > vfio_put_device(&hisi_acc_vdev->core_device.vdev); > } > > diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h > index c58fc5861492..38327b97d535 100644 > --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h > +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h > @@ -116,5 +116,10 @@ struct hisi_acc_vf_core_device { > spinlock_t reset_lock; > struct hisi_acc_vf_migration_file *resuming_migf; > struct hisi_acc_vf_migration_file *saving_migf; > + > + /* To make sure the device is enabled */ > + struct mutex enable_mutex; > + /* For debugfs */ > + struct hisi_acc_vf_migration_file *debug_migf; > }; > #endif /* HISI_ACC_VFIO_PCI_H */