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SubjectRe: [Qemu-devel] [PATCH v2 2/2] vfio : add aer process
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Hi, Alex

On 2016/7/30 1:12, Alex Williamson wrote:
> On Tue, 19 Jul 2016 15:32:43 +0800
> Zhou Jie <zhoujie2011@cn.fujitsu.com> wrote:
>
>> From: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
>>
>> During aer err occurs and resume do following to
>> protect device from being accessed.
>> 1. Make config space read only.
>> 2. Disable INTx/MSI Interrupt.
>> 3. Do nothing for bar regions.
>>
>> Signed-off-by: Zhou Jie <zhoujie2011@cn.fujitsu.com>
>> ---
>> drivers/vfio/pci/vfio_pci.c | 30 ++++++++++++++++++++++++++++++
>> drivers/vfio/pci/vfio_pci_private.h | 2 ++
>> include/uapi/linux/vfio.h | 2 ++
>> 3 files changed, 34 insertions(+)
>>
>> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
>> index 2d12b03..dd96b60 100644
>> --- a/drivers/vfio/pci/vfio_pci.c
>> +++ b/drivers/vfio/pci/vfio_pci.c
>> @@ -318,6 +318,7 @@ static int vfio_pci_open(void *device_data)
>> return -ENODEV;
>>
>> mutex_lock(&driver_lock);
>> + init_completion(&vdev->aer_error_completion);
>>
>> if (!vdev->refcnt) {
>> ret = vfio_pci_enable(vdev);
>> @@ -571,6 +572,16 @@ static long vfio_pci_ioctl(void *device_data,
>> struct vfio_pci_device *vdev = device_data;
>> unsigned long minsz;
>>
>> + if (vdev->aer_error_in_progress && (cmd == VFIO_DEVICE_SET_IRQS ||
>> + cmd == VFIO_DEVICE_RESET || cmd == VFIO_DEVICE_PCI_HOT_RESET)) {
>> + int ret;
>> + ret = wait_for_completion_interruptible(
>> + &vdev->aer_error_completion);
>> + if (ret) {
>> + return ret;
>> + }
>
> No brackets necessary.
>
>> + }
>> +
>> if (cmd == VFIO_DEVICE_GET_INFO) {
>> struct vfio_device_info info;
>>
>> @@ -587,6 +598,10 @@ static long vfio_pci_ioctl(void *device_data,
>> if (vdev->reset_works)
>> info.flags |= VFIO_DEVICE_FLAGS_RESET;
>>
>> + info.flags |= VFIO_DEVICE_FLAGS_AERPROCESS;
>> + if (vdev->aer_error_in_progress)
>> + info.flags |= VFIO_DEVICE_FLAGS_INAERPROCESS;
>> +
>> info.num_regions = VFIO_PCI_NUM_REGIONS + vdev->num_regions;
>> info.num_irqs = VFIO_PCI_NUM_IRQS;
>>
>> @@ -996,6 +1011,14 @@ static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
>>
>> switch (index) {
>> case VFIO_PCI_CONFIG_REGION_INDEX:
>> + if (vdev->aer_error_in_progress && iswrite) {
>> + int ret;
>> + ret = wait_for_completion_interruptible(
>> + &vdev->aer_error_completion);
>> + if (ret) {
>> + return ret;
>> + }
>> + }
>> return vfio_pci_config_rw(vdev, buf, count, ppos, iswrite);
>>
>> case VFIO_PCI_ROM_REGION_INDEX:
>> @@ -1226,6 +1249,10 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
>>
>> mutex_lock(&vdev->igate);
>>
>> + vdev->aer_error_in_progress = true;
>> + vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
>> + VFIO_IRQ_SET_ACTION_TRIGGER,
>> + vdev->irq_type, 0, 0, NULL);
>> if (vdev->err_trigger)
>> eventfd_signal(vdev->err_trigger, 1);
>>
>> @@ -1252,6 +1279,9 @@ static void vfio_pci_aer_resume(struct pci_dev *pdev)
>> }
>>
>> mutex_lock(&vdev->igate);
>> +
>> + vdev->aer_error_in_progress = false;
>> + complete_all(&vdev->aer_error_completion);
>> if (vdev->resume_trigger)
>> eventfd_signal(vdev->resume_trigger, 1);
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
>> index 80d4ddd..2f151f5 100644
>> --- a/drivers/vfio/pci/vfio_pci_private.h
>> +++ b/drivers/vfio/pci/vfio_pci_private.h
>> @@ -84,6 +84,8 @@ struct vfio_pci_device {
>> bool has_vga;
>> bool needs_reset;
>> bool nointx;
>> + bool aer_error_in_progress;
>> + struct completion aer_error_completion;
>> struct pci_saved_state *pci_saved_state;
>> int refcnt;
>> struct eventfd_ctx *err_trigger;
>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> index 34ab138..276ce50 100644
>> --- a/include/uapi/linux/vfio.h
>> +++ b/include/uapi/linux/vfio.h
>> @@ -198,6 +198,8 @@ struct vfio_device_info {
>> #define VFIO_DEVICE_FLAGS_PCI (1 << 1) /* vfio-pci device */
>> #define VFIO_DEVICE_FLAGS_PLATFORM (1 << 2) /* vfio-platform device */
>> #define VFIO_DEVICE_FLAGS_AMBA (1 << 3) /* vfio-amba device */
>> +#define VFIO_DEVICE_FLAGS_AERPROCESS (1 << 4) /* support aer error progress */
>> +#define VFIO_DEVICE_FLAGS_INAERPROCESS (1 << 5)/* status in aer error progress */
>> __u32 num_regions; /* Max region index + 1 */
>> __u32 num_irqs; /* Max IRQ index + 1 */
>> };
>
> Clearly this has only been tested for a single instance of an AER error
> event and resume per device. Are the things you're intending to block
> actually blocked for subsequent events? Note how complete_all() fills
> the done field to let all current and future waiters go through and
> nowhere is there a call to reinit_completion() to drain that path.
> Thanks,
>
> Alex

Do you mean this condition?

For device 1:
error1 occurs ---- error1 resumes
error2 occurs ---- error2 resumes
error3 occurs ---- error3 resumes

In current code, I do complete_all() when error1 resumes.
And this will unblock the device
when error2 and error3 are still be processed.

Sincerely
ZhouJie


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