[PATCH 0/3] add debugfs to hisilicon migration driver

[PATCH 0/3] add debugfs to hisilicon migration driver

[Longfang Liu]

Add a debugfs function to the hisilicon migration driver in VFIO to
provide intermediate state values and data during device migration.

When the execution of live migration fails, the user can view the
status and data during the migration process separately from the
source and the destination, which is convenient for users to analyze
and locate problems.

Longfang Liu (3):
  hisi_acc_vfio_pci: extract public functions for container_of
  hisi_acc_vfio_pci: register debugfs for hisilicon migration driver
  Documentation: add debugfs description for hisi migration

 .../ABI/testing/debugfs-hisi-migration        |  34 +++
 MAINTAINERS                                   |   1 +
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 211 +++++++++++++++++-
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   5 +
 4 files changed, 241 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration

-- 
2.24.0

[PATCH 1/3] hisi_acc_vfio_pci: extract public functions for container_of

[Longfang Liu]

In the current driver, vdev is obtained from struct
hisi_acc_vf_core_device through the container_of function.
This method is used in many places in the driver. In order to
reduce this repetitive operation, I extracted a public function
to replace it.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index f4b38a243aa7..5f6e01571a7b 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -641,6 +641,12 @@ static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vde
 	}
 }
 
+static struct hisi_acc_vf_core_device *hisi_acc_get_vf_dev(struct vfio_device *vdev)
+{
+	return container_of(vdev, struct hisi_acc_vf_core_device,
+			    core_device.vdev);
+}
+
 /*
  * This function is called in all state_mutex unlock cases to
  * handle a 'deferred_reset' if exists.
@@ -1064,8 +1070,7 @@ static struct file *
 hisi_acc_vfio_pci_set_device_state(struct vfio_device *vdev,
 				   enum vfio_device_mig_state new_state)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
 	enum vfio_device_mig_state next_state;
 	struct file *res = NULL;
 	int ret;
@@ -1106,8 +1111,7 @@ static int
 hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
 				   enum vfio_device_mig_state *curr_state)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
 
 	mutex_lock(&hisi_acc_vdev->state_mutex);
 	*curr_state = hisi_acc_vdev->mig_state;
@@ -1323,8 +1327,7 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
 
 static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct vfio_pci_core_device *vdev = &hisi_acc_vdev->core_device;
 	int ret;
 
@@ -1347,8 +1350,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 
 static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.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;
 
 	iounmap(vf_qm->io_base);
@@ -1363,8 +1365,7 @@ static const struct vfio_migration_ops hisi_acc_vfio_pci_migrn_state_ops = {
 
 static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct pci_dev *pdev = to_pci_dev(core_vdev->dev);
 	struct hisi_qm *pf_qm = hisi_acc_get_pf_qm(pdev);
 
-- 
2.24.0

Re: [PATCH 1/3] hisi_acc_vfio_pci: extract public functions for container_of

[Zhi Wang]

On Thu, 25 Jan 2024 16:10:29 +0800
Longfang Liu <liulongfang@huawei.com> wrote:

> In the current driver, vdev is obtained from struct
> hisi_acc_vf_core_device through the container_of function.
> This method is used in many places in the driver. In order to
> reduce this repetitive operation, I extracted a public function
> to replace it.
> 
It is better to use the passive voice in the patch comment.
> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> ---
>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 21
> ++++++++++--------- 1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index
> f4b38a243aa7..5f6e01571a7b 100644 ---
> a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c +++
> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c @@ -641,6 +641,12 @@
> static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device
> *hisi_acc_vde } }
>  
> +static struct hisi_acc_vf_core_device *hisi_acc_get_vf_dev(struct
> vfio_device *vdev) +{
> +	return container_of(vdev, struct hisi_acc_vf_core_device,
> +			    core_device.vdev);
> +}
> +
>  /*
>   * This function is called in all state_mutex unlock cases to
>   * handle a 'deferred_reset' if exists.
> @@ -1064,8 +1070,7 @@ static struct file *
>  hisi_acc_vfio_pci_set_device_state(struct vfio_device *vdev,
>  				   enum vfio_device_mig_state
> new_state) {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> container_of(vdev,
> -			struct hisi_acc_vf_core_device,
> core_device.vdev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> hisi_acc_get_vf_dev(vdev); enum vfio_device_mig_state next_state;
>  	struct file *res = NULL;
>  	int ret;
> @@ -1106,8 +1111,7 @@ static int
>  hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
>  				   enum vfio_device_mig_state
> *curr_state) {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> container_of(vdev,
> -			struct hisi_acc_vf_core_device,
> core_device.vdev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> hisi_acc_get_vf_dev(vdev); 
>  	mutex_lock(&hisi_acc_vdev->state_mutex);
>  	*curr_state = hisi_acc_vdev->mig_state;
> @@ -1323,8 +1327,7 @@ static long hisi_acc_vfio_pci_ioctl(struct
> vfio_device *core_vdev, unsigned int 
>  static int hisi_acc_vfio_pci_open_device(struct vfio_device
> *core_vdev) {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> container_of(core_vdev,
> -			struct hisi_acc_vf_core_device,
> core_device.vdev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> hisi_acc_get_vf_dev(core_vdev); struct vfio_pci_core_device *vdev =
> &hisi_acc_vdev->core_device; int ret;
>  
> @@ -1347,8 +1350,7 @@ static int hisi_acc_vfio_pci_open_device(struct
> vfio_device *core_vdev) 
>  static void hisi_acc_vfio_pci_close_device(struct vfio_device
> *core_vdev) {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> container_of(core_vdev,
> -			struct hisi_acc_vf_core_device,
> core_device.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; 
>  	iounmap(vf_qm->io_base);
> @@ -1363,8 +1365,7 @@ static const struct vfio_migration_ops
> hisi_acc_vfio_pci_migrn_state_ops = { 
>  static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device
> *core_vdev) {
> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> container_of(core_vdev,
> -			struct hisi_acc_vf_core_device,
> core_device.vdev);
> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
> hisi_acc_get_vf_dev(core_vdev); struct pci_dev *pdev =
> to_pci_dev(core_vdev->dev); struct hisi_qm *pf_qm =
> hisi_acc_get_pf_qm(pdev); 

Re: [PATCH 1/3] hisi_acc_vfio_pci: extract public functions for container_of

[liulongfang]

On 2024/1/26 5:48, Zhi Wang wrote:
> On Thu, 25 Jan 2024 16:10:29 +0800
> Longfang Liu <liulongfang@huawei.com> wrote:
> 
>> In the current driver, vdev is obtained from struct
>> hisi_acc_vf_core_device through the container_of function.
>> This method is used in many places in the driver. In order to
>> reduce this repetitive operation, I extracted a public function
>> to replace it.
>>
> It is better to use the passive voice in the patch comment.

OK,

Thanks,
Longfang.
>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>> ---
>>  .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 21
>> ++++++++++--------- 1 file changed, 11 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
>> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index
>> f4b38a243aa7..5f6e01571a7b 100644 ---
>> a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c +++
>> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c @@ -641,6 +641,12 @@
>> static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device
>> *hisi_acc_vde } }
>>  
>> +static struct hisi_acc_vf_core_device *hisi_acc_get_vf_dev(struct
>> vfio_device *vdev) +{
>> +	return container_of(vdev, struct hisi_acc_vf_core_device,
>> +			    core_device.vdev);
>> +}
>> +
>>  /*
>>   * This function is called in all state_mutex unlock cases to
>>   * handle a 'deferred_reset' if exists.
>> @@ -1064,8 +1070,7 @@ static struct file *
>>  hisi_acc_vfio_pci_set_device_state(struct vfio_device *vdev,
>>  				   enum vfio_device_mig_state
>> new_state) {
>> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> container_of(vdev,
>> -			struct hisi_acc_vf_core_device,
>> core_device.vdev);
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> hisi_acc_get_vf_dev(vdev); enum vfio_device_mig_state next_state;
>>  	struct file *res = NULL;
>>  	int ret;
>> @@ -1106,8 +1111,7 @@ static int
>>  hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
>>  				   enum vfio_device_mig_state
>> *curr_state) {
>> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> container_of(vdev,
>> -			struct hisi_acc_vf_core_device,
>> core_device.vdev);
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> hisi_acc_get_vf_dev(vdev); 
>>  	mutex_lock(&hisi_acc_vdev->state_mutex);
>>  	*curr_state = hisi_acc_vdev->mig_state;
>> @@ -1323,8 +1327,7 @@ static long hisi_acc_vfio_pci_ioctl(struct
>> vfio_device *core_vdev, unsigned int 
>>  static int hisi_acc_vfio_pci_open_device(struct vfio_device
>> *core_vdev) {
>> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> container_of(core_vdev,
>> -			struct hisi_acc_vf_core_device,
>> core_device.vdev);
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> hisi_acc_get_vf_dev(core_vdev); struct vfio_pci_core_device *vdev =
>> &hisi_acc_vdev->core_device; int ret;
>>  
>> @@ -1347,8 +1350,7 @@ static int hisi_acc_vfio_pci_open_device(struct
>> vfio_device *core_vdev) 
>>  static void hisi_acc_vfio_pci_close_device(struct vfio_device
>> *core_vdev) {
>> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> container_of(core_vdev,
>> -			struct hisi_acc_vf_core_device,
>> core_device.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; 
>>  	iounmap(vf_qm->io_base);
>> @@ -1363,8 +1365,7 @@ static const struct vfio_migration_ops
>> hisi_acc_vfio_pci_migrn_state_ops = { 
>>  static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device
>> *core_vdev) {
>> -	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> container_of(core_vdev,
>> -			struct hisi_acc_vf_core_device,
>> core_device.vdev);
>> +	struct hisi_acc_vf_core_device *hisi_acc_vdev =
>> hisi_acc_get_vf_dev(core_vdev); struct pci_dev *pdev =
>> to_pci_dev(core_vdev->dev); struct hisi_qm *pf_qm =
>> hisi_acc_get_pf_qm(pdev); 
> 
> .
> 

[PATCH 2/3] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Longfang Liu]

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
    |
    +---<dev_name1>
    |    +---migration
    |        +--state
    |        +--hisi_acc
    |            +--attr
    |            +--data
    |            +--save
    |            +--cmd_state
    |
    +---<dev_name2>
         +---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 <liulongfang@huawei.com>
---
 .../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 <linux/anon_inodes.h>
 
 #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;
+	}
+
+	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 */
-- 
2.24.0

Re: [PATCH 2/3] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Alex Williamson]

On Thu, 25 Jan 2024 16:10:30 +0800
Longfang Liu <liulongfang@huawei.com> 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
>     |
>     +---<dev_name1>
>     |    +---migration
>     |        +--state
>     |        +--hisi_acc
>     |            +--attr
>     |            +--data
>     |            +--save
>     |            +--cmd_state
>     |
>     +---<dev_name2>
>          +---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 <liulongfang@huawei.com>
> ---
>  .../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 <linux/anon_inodes.h>
>  
>  #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 */

Re: [PATCH 2/3] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[liulongfang]

On 2024/1/26 6:38, Alex Williamson wrote:
> On Thu, 25 Jan 2024 16:10:30 +0800
> Longfang Liu <liulongfang@huawei.com> 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
>>     |
>>     +---<dev_name1>
>>     |    +---migration
>>     |        +--state
>>     |        +--hisi_acc
>>     |            +--attr
>>     |            +--data
>>     |            +--save
>>     |            +--cmd_state
>>     |
>>     +---<dev_name2>
>>          +---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 <liulongfang@huawei.com>
>> ---
>>  .../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 <linux/anon_inodes.h>
>>  
>>  #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.
>

Yes, this enable_mutex is used to protect io_base. It prevents debugfs
from being used after executing iounmap in io_base.

> 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,
>

OK An atomic variable needs to be added to replace vdev->open_count to prevent
competition. And use enable_mutex to prevent io_base from being released early.


Thanks,
Longfang.

> 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 */
> 
> .
> 

Re: [PATCH 2/3] hisi_acc_vfio_pci: register debugfs for hisilicon migration driver

[Alex Williamson]

On Mon, 29 Jan 2024 10:24:00 +0800
liulongfang <liulongfang@huawei.com> wrote:

> On 2024/1/26 6:38, Alex Williamson wrote:
> > On Thu, 25 Jan 2024 16:10:30 +0800
> > Longfang Liu <liulongfang@huawei.com> 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
> >>     |
> >>     +---<dev_name1>
> >>     |    +---migration
> >>     |        +--state
> >>     |        +--hisi_acc
> >>     |            +--attr
> >>     |            +--data
> >>     |            +--save
> >>     |            +--cmd_state
> >>     |
> >>     +---<dev_name2>
> >>          +---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 <liulongfang@huawei.com>
> >> ---
> >>  .../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 <linux/anon_inodes.h>
> >>  
> >>  #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.
> >  
> 
> Yes, this enable_mutex is used to protect io_base. It prevents debugfs
> from being used after executing iounmap in io_base.
> 
> > 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,
> >  
> 
> OK An atomic variable needs to be added to replace vdev->open_count to prevent
> competition. And use enable_mutex to prevent io_base from being released early.

That's not what I'm suggesting, open_count is safe in the core code, it
doesn't need to be an atomic.  Your use of it is unsafe.  enable_mutex
doesn't protect what it intends to protect.  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 */  
> > 
> > .
> >   
> 

[PATCH 3/3] Documentation: add debugfs description for hisi migration

[Longfang Liu]

Add a debugfs document description file to help users understand
how to use the hisilicon accelerator live migration driver's
debugfs.

Update the file paths that need to be maintained in MAINTAINERS

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
---
 .../ABI/testing/debugfs-hisi-migration        | 34 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 35 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration

diff --git a/Documentation/ABI/testing/debugfs-hisi-migration b/Documentation/ABI/testing/debugfs-hisi-migration
new file mode 100644
index 000000000000..d61255c3bcd9
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-hisi-migration
@@ -0,0 +1,34 @@
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/data
+Date:		JAN 2024
+KernelVersion:  6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Read the live migration data of the vfio device.
+		These data include device status data, queue configuration
+		data and some task configuration data.
+		The output format of the data is defined by the live
+		migration driver.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/attr
+Date:		JAN 2024
+KernelVersion:  6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Read the live migration attributes of the vfio device.
+		it include device status attributes and data length attributes
+		The output format of the attributes is defined by the live
+		migration driver.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/cmd_state
+Date:		JAN 2024
+KernelVersion:  6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Used to obtain the device command sending and receiving
+		channel status. If successful, returns the command value.
+		If failed, return error log.
+
+What:		/sys/kernel/debug/vfio/<device>/migration/hisi_acc/save
+Date:		JAN 2024
+KernelVersion:  6.8
+Contact:	Longfang Liu <liulongfang@huawei.com>
+Description:	Trigger the Hisilicon accelerator device to perform
+		the state saving operation of live migration through the read
+		operation, and output the operation log results.
diff --git a/MAINTAINERS b/MAINTAINERS
index 20f8e9872deb..115d43d307e8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22856,6 +22856,7 @@ M:	Longfang Liu <liulongfang@huawei.com>
 M:	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
 L:	kvm@vger.kernel.org
 S:	Maintained
+F:	Documentation/ABI/testing/debugfs-hisi-migration
 F:	drivers/vfio/pci/hisilicon/
 
 VFIO MEDIATED DEVICE DRIVERS
-- 
2.24.0

[PATCH 0/3] add debugfs to hisilicon migration driver

[Longfang Liu]

Add a debugfs function to the hisilicon migration driver in VFIO to
provide intermediate state values and data during device migration.

When the execution of live migration fails, the user can view the
status and data during the migration process separately from the
source and the destination, which is convenient for users to analyze
and locate problems.

Longfang Liu (3):
  hisi_acc_vfio_pci: extract public functions for container_of
  hisi_acc_vfio_pci: register debugfs for hisilicon migration driver
  Documentation: add debugfs description for hisi migration

 .../ABI/testing/debugfs-hisi-migration        |  34 +++
 MAINTAINERS                                   |   1 +
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 211 +++++++++++++++++-
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |   5 +
 4 files changed, 241 insertions(+), 10 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-hisi-migration

-- 
2.24.0

[PATCH 1/3] hisi_acc_vfio_pci: extract public functions for container_of

[Longfang Liu]

In the current driver, vdev is obtained from struct
hisi_acc_vf_core_device through the container_of function.
This method is used in many places in the driver. In order to
reduce this repetitive operation, I extracted a public function
to replace it.

Signed-off-by: Longfang Liu <liulongfang@huawei.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index f4b38a243aa7..5f6e01571a7b 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -641,6 +641,12 @@ static void hisi_acc_vf_disable_fds(struct hisi_acc_vf_core_device *hisi_acc_vde
 	}
 }
 
+static struct hisi_acc_vf_core_device *hisi_acc_get_vf_dev(struct vfio_device *vdev)
+{
+	return container_of(vdev, struct hisi_acc_vf_core_device,
+			    core_device.vdev);
+}
+
 /*
  * This function is called in all state_mutex unlock cases to
  * handle a 'deferred_reset' if exists.
@@ -1064,8 +1070,7 @@ static struct file *
 hisi_acc_vfio_pci_set_device_state(struct vfio_device *vdev,
 				   enum vfio_device_mig_state new_state)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
 	enum vfio_device_mig_state next_state;
 	struct file *res = NULL;
 	int ret;
@@ -1106,8 +1111,7 @@ static int
 hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
 				   enum vfio_device_mig_state *curr_state)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(vdev);
 
 	mutex_lock(&hisi_acc_vdev->state_mutex);
 	*curr_state = hisi_acc_vdev->mig_state;
@@ -1323,8 +1327,7 @@ static long hisi_acc_vfio_pci_ioctl(struct vfio_device *core_vdev, unsigned int
 
 static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct vfio_pci_core_device *vdev = &hisi_acc_vdev->core_device;
 	int ret;
 
@@ -1347,8 +1350,7 @@ static int hisi_acc_vfio_pci_open_device(struct vfio_device *core_vdev)
 
 static void hisi_acc_vfio_pci_close_device(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.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;
 
 	iounmap(vf_qm->io_base);
@@ -1363,8 +1365,7 @@ static const struct vfio_migration_ops hisi_acc_vfio_pci_migrn_state_ops = {
 
 static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev)
 {
-	struct hisi_acc_vf_core_device *hisi_acc_vdev = container_of(core_vdev,
-			struct hisi_acc_vf_core_device, core_device.vdev);
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_get_vf_dev(core_vdev);
 	struct pci_dev *pdev = to_pci_dev(core_vdev->dev);
 	struct hisi_qm *pf_qm = hisi_acc_get_pf_qm(pdev);
 
-- 
2.24.0