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Mon, 24 Jul 2023 11:14:50 +0800 Subject: Re: [PATCH v11 3/4] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver To: Alex Williamson CC: , , , , , References: <20230630092457.54902-1-liulongfang@huawei.com> <20230630092457.54902-4-liulongfang@huawei.com> <20230714160751.551df645.alex.williamson@redhat.com> From: liulongfang Message-ID: Date: Mon, 24 Jul 2023 11:14:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20230714160751.551df645.alex.williamson@redhat.com> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.103.158] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600005.china.huawei.com (7.193.23.191) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/7/15 6:07, Alex Williamson wrote: > On Fri, 30 Jun 2023 17:24:56 +0800 > liulongfang wrote: > >> From: Longfang Liu >> >> On the debugfs framework of VFIO, if the CONFIG_DEBUG_FS 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: >> >> 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. >> io_test: used to test IO read and write for the driver. >> >> Signed-off-by: Longfang Liu >> --- >> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 182 ++++++++++++++++++ >> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 11 ++ >> 2 files changed, 193 insertions(+) >> >> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c >> index a1589947e721..a6f5e94bfaf2 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) >> @@ -606,6 +607,18 @@ 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 *src_migf, >> + struct hisi_acc_vf_migration_file *dst_migf) > > Consider swapping the args to be more consistent with functions like > memcpy() where the destination is the first arg and source is the > second.> OK, These two parameters can be swapped. >> +{ >> + 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); >> @@ -618,12 +631,16 @@ 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->resuming_migf, >> + hisi_acc_vdev->debug_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->saving_migf, >> + hisi_acc_vdev->debug_migf); >> hisi_acc_vf_disable_fd(hisi_acc_vdev->saving_migf); >> fput(hisi_acc_vdev->saving_migf->filp); >> hisi_acc_vdev->saving_migf = NULL; >> @@ -1303,6 +1320,164 @@ 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 not support debugfs!"); > > "device does not support debugfs"? > OK,"device does not support live migration" >> + return -EINVAL; >> + } >> + >> + /* If device not opened, the debugfs operation will trigger calltrace */ >> + if (!vdev->open_count) { >> + seq_printf(seq, "%s\n", "device not opened!"); >> + return -EINVAL; >> + } > > What prevents this from racing release of the device? > Now there are only read operations for debugfs. The open_count here only needs to be used to prevent read operations when the device is not opened. There is no need to deal with competition issues. >> + >> + return 0; >> +} >> + >> +static int hisi_acc_vf_debug_io(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; > > A tab sneaked in here. > Thanks. >> + 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) >> + goto io_err; >> + >> + ret = qm_wait_dev_not_ready(vf_qm); >> + if (ret) { >> + seq_printf(seq, "%s\n", "VF device not ready!"); >> + goto io_err; >> + } >> + >> + value = readl(vf_qm->io_base + QM_MB_CMD_SEND_BASE); >> + seq_printf(seq, "%s:0x%llx\n", "debug mailbox val", value); >> + >> +io_err: >> + return 0; > > A goto that simply returns seems unnecessary vs return at the error Ok, no need to use goto here. The following one is also handled in the same way. > condition. Also why don't we return the errno for error cases? Do we> even need seq_printf() calls for error cases? > Added logging of seq_printf only on critical steps. >> +} >> + >> +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; > > Another tab. > OK. >> + 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) >> + goto save_err; >> + >> + ret = vf_qm_state_save(hisi_acc_vdev, migf); >> + if (ret) { >> + seq_printf(seq, "%s\n", "failed to save device data!"); >> + goto save_err; >> + } >> + seq_printf(seq, "%s\n", "successful to save device data!"); >> + >> +save_err: >> + 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; > > Tab. > OK. >> + 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; > > Tab. > OK. >> + 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) { >> + 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, "io_test", vfio_hisi_acc, >> + hisi_acc_vf_debug_io); >> + 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); >> @@ -1323,6 +1498,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev) >> } >> >> vfio_pci_core_finish_enable(vdev); >> + >> return 0; >> } >> >> @@ -1420,9 +1596,14 @@ 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: >> + if (ops == &hisi_acc_vfio_pci_migrn_ops) >> + hisi_acc_vf_debugfs_exit(hisi_acc_vdev); > > Why do we need this? There's no case where debug_init occurs before > this goto. > Yes. These two lines are not needed here. >> vfio_put_device(&hisi_acc_vdev->core_device.vdev); >> return ret; >> } >> @@ -1431,6 +1612,7 @@ static void hisi_acc_vfio_pci_remove(struct pci_dev *pdev) >> { >> struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev); >> >> + hisi_acc_vf_debugfs_exit(hisi_acc_vdev); >> vfio_pci_core_unregister_device(&hisi_acc_vdev->core_device); >> 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 dcabfeec6ca1..ef50b12f018d 100644 >> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h >> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h >> @@ -49,6 +49,14 @@ >> #define QM_EQC_DW0 0X8000 >> #define QM_AEQC_DW0 0X8020 >> >> +#define VFIO_DEV_DBG_LEN 256 >> + >> +enum mig_debug_cmd { >> + STATE_SAVE, >> + STATE_RESUME, >> + RW_IO_TEST, >> +}; > > Unused. > OK. > Thanks, > Alex > Thanks, Longfang. >> + >> struct acc_vf_data { >> #define QM_MATCH_SIZE offsetofend(struct acc_vf_data, qm_rsv_state) >> /* QM match information */ >> @@ -113,5 +121,8 @@ 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; >> + >> + /* For debugfs */ >> + struct hisi_acc_vf_migration_file *debug_migf; >> }; >> #endif /* HISI_ACC_VFIO_PCI_H */ > > . >