diff mbox series

[SRU,J:linux-bluefield,v3,3/6] UBUNTU: SAUCE: vfio_pci: Do not open code pci_try_reset_function()

Message ID 20240906194908.1127733-4-witu@nvidia.com
State New
Headers show
Series Add VFIO P2P support | expand

Commit Message

William Tu Sept. 6, 2024, 7:49 p.m. UTC 
From: Jason Gunthorpe <jgg@nvidia.com>

BugLink: https://bugs.launchpad.net/bugs/2077887

FLR triggered by an emulated config space write should not behave
differently from a FLR triggered by VFIO_DEVICE_RESET, currently the
config space path misses the power management.

Consolidate all the call sites to invoke a single function.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: William Tu <witu@nvidia.com>
---
 drivers/vfio/pci/vfio_pci_config.c | 14 +++-------
 drivers/vfio/pci/vfio_pci_core.c   | 41 +++++++++++++-----------------
 drivers/vfio/pci/vfio_pci_priv.h   |  7 +++++
 3 files changed, 28 insertions(+), 34 deletions(-)
 create mode 100644 drivers/vfio/pci/vfio_pci_priv.h

Comments

Bartlomiej Zolnierkiewicz Sept. 11, 2024, 7:52 a.m. UTC | #1 
On Fri, Sep 6, 2024 at 9:50 PM William Tu <witu@nvidia.com> wrote:
>
> From: Jason Gunthorpe <jgg@nvidia.com>
>
> BugLink: https://bugs.launchpad.net/bugs/2077887
>
> FLR triggered by an emulated config space write should not behave
> differently from a FLR triggered by VFIO_DEVICE_RESET, currently the
> config space path misses the power management.

After this patch all paths seem to miss the power management, please see below.

> Consolidate all the call sites to invoke a single function.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: William Tu <witu@nvidia.com>
> ---
>  drivers/vfio/pci/vfio_pci_config.c | 14 +++-------
>  drivers/vfio/pci/vfio_pci_core.c   | 41 +++++++++++++-----------------
>  drivers/vfio/pci/vfio_pci_priv.h   |  7 +++++
>  3 files changed, 28 insertions(+), 34 deletions(-)
>  create mode 100644 drivers/vfio/pci/vfio_pci_priv.h
>
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index 6e58b4bf7a60..78c626b8907d 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -857,11 +857,8 @@ static int vfio_exp_config_write(struct vfio_pci_core_device *vdev, int pos,
>                                                  pos - offset + PCI_EXP_DEVCAP,
>                                                  &cap);
>
> -               if (!ret && (cap & PCI_EXP_DEVCAP_FLR)) {
> -                       vfio_pci_zap_and_down_write_memory_lock(vdev);
> -                       pci_try_reset_function(vdev->pdev);
> -                       up_write(&vdev->memory_lock);
> -               }
> +               if (!ret && (cap & PCI_EXP_DEVCAP_FLR))
> +                       vfio_pci_try_reset_function(vdev);
>         }
>
>         /*
> @@ -939,11 +936,8 @@ static int vfio_af_config_write(struct vfio_pci_core_device *vdev, int pos,
>                                                 pos - offset + PCI_AF_CAP,
>                                                 &cap);
>
> -               if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP)) {
> -                       vfio_pci_zap_and_down_write_memory_lock(vdev);
> -                       pci_try_reset_function(vdev->pdev);
> -                       up_write(&vdev->memory_lock);
> -               }
> +               if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP))
> +                       vfio_pci_try_reset_function(vdev);
>         }
>
>         return count;
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 4f1aceadd4fb..5904801f6f77 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -29,6 +29,8 @@
>
>  #include <linux/vfio_pci_core.h>
>
> +#include "vfio_pci_priv.h"
> +
>  #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
>  #define DRIVER_DESC "core driver for VFIO based PCI devices"
>
> @@ -648,6 +650,20 @@ int vfio_pci_register_dev_region(struct vfio_pci_core_device *vdev,
>  }
>  EXPORT_SYMBOL_GPL(vfio_pci_register_dev_region);
>
> +int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev)
> +{
> +       int ret;
> +
> +       if (!vdev->reset_works)
> +               return -EINVAL;
> +
> +       vfio_pci_zap_and_down_write_memory_lock(vdev);
> +       ret = pci_try_reset_function(vdev->pdev);
> +       up_write(&vdev->memory_lock);
> +
> +       return ret;
> +}
> +
>  long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
>                 unsigned long arg)
>  {
> @@ -929,30 +945,7 @@ long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
>                 return ret;
>
>         } else if (cmd == VFIO_DEVICE_RESET) {
> -               int ret;
> -
> -               if (!vdev->reset_works)
> -                       return -EINVAL;
> -
> -               vfio_pci_zap_and_down_write_memory_lock(vdev);
> -
> -               /*
> -                * This function can be invoked while the power state is non-D0.
> -                * If pci_try_reset_function() has been called while the power
> -                * state is non-D0, then pci_try_reset_function() will
> -                * internally set the power state to D0 without vfio driver
> -                * involvement. For the devices which have NoSoftRst-, the
> -                * reset function can cause the PCI config space reset without
> -                * restoring the original state (saved locally in
> -                * 'vdev->pm_save').
> -                */
> -               vfio_pci_set_power_state(vdev, PCI_D0);

The above call is missing from vfio_pci_try_reset_function(), is this
correct/intended?

--
Best regards,
Bartlomiej

> -
> -               ret = pci_try_reset_function(vdev->pdev);
> -               up_write(&vdev->memory_lock);
> -
> -               return ret;
> -
> +               return vfio_pci_try_reset_function(vdev);
>         } else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {
>                 struct vfio_pci_hot_reset_info hdr;
>                 struct vfio_pci_fill_info fill = { 0 };
> diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
> new file mode 100644
> index 000000000000..4971cd95b431
> --- /dev/null
> +++ b/drivers/vfio/pci/vfio_pci_priv.h
> @@ -0,0 +1,7 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef VFIO_PCI_PRIV_H
> +#define VFIO_PCI_PRIV_H
> +
> +int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev);
> +
> +#endif
William Tu Sept. 11, 2024, 2:53 p.m. UTC | #2 
Hi Bartlomiej,

Thanks for your review!
Following the original patch
https://patchwork.kernel.org/project/linux-rdma/patch/3-v2-472615b3877e+28f7-vfio_dma_buf_jgg@nvidia.com/

The
               vfio_pci_set_power_state(vdev, PCI_D0);
is no longer needed, as it is done in
               pci_dev_save_and_disable

call trace is like
vfio_pci_try_reset_function
                pci_dev_save_and_disable
pci_set_power_state(dev, PCI_D0);

Thanks
William

From: Bartlomiej Zolnierkiewicz <bartlomiej.zolnierkiewicz@canonical.com>
Date: Wednesday, September 11, 2024 at 12:52 AM
To: William Tu <witu@nvidia.com>
Cc: kernel-team@lists.ubuntu.com <kernel-team@lists.ubuntu.com>, Vladimir Sokolovsky <vlad@nvidia.com>, Bodong Wang <bodong@nvidia.com>, Sergey Gorenko <sergeygo@nvidia.com>, Jason Gunthorpe <jgg@nvidia.com>, Ziv Waksman <zwaksman@nvidia.com>
Subject: Re: [SRU][J:linux-bluefield][PATCH v3 3/6] UBUNTU: SAUCE: vfio_pci: Do not open code pci_try_reset_function()
External email: Use caution opening links or attachments


On Fri, Sep 6, 2024 at 9:50 PM William Tu <witu@nvidia.com> wrote:
>
> From: Jason Gunthorpe <jgg@nvidia.com>
>
> BugLink: https://bugs.launchpad.net/bugs/2077887
>
> FLR triggered by an emulated config space write should not behave
> differently from a FLR triggered by VFIO_DEVICE_RESET, currently the
> config space path misses the power management.

After this patch all paths seem to miss the power management, please see below.

> Consolidate all the call sites to invoke a single function.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: William Tu <witu@nvidia.com>
> ---
>  drivers/vfio/pci/vfio_pci_config.c | 14 +++-------
>  drivers/vfio/pci/vfio_pci_core.c   | 41 +++++++++++++-----------------
>  drivers/vfio/pci/vfio_pci_priv.h   |  7 +++++
>  3 files changed, 28 insertions(+), 34 deletions(-)
>  create mode 100644 drivers/vfio/pci/vfio_pci_priv.h
>
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index 6e58b4bf7a60..78c626b8907d 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -857,11 +857,8 @@ static int vfio_exp_config_write(struct vfio_pci_core_device *vdev, int pos,
>                                                  pos - offset + PCI_EXP_DEVCAP,
>                                                  &cap);
>
> -               if (!ret && (cap & PCI_EXP_DEVCAP_FLR)) {
> -                       vfio_pci_zap_and_down_write_memory_lock(vdev);
> -                       pci_try_reset_function(vdev->pdev);
> -                       up_write(&vdev->memory_lock);
> -               }
> +               if (!ret && (cap & PCI_EXP_DEVCAP_FLR))
> +                       vfio_pci_try_reset_function(vdev);
>         }
>
>         /*
> @@ -939,11 +936,8 @@ static int vfio_af_config_write(struct vfio_pci_core_device *vdev, int pos,
>                                                 pos - offset + PCI_AF_CAP,
>                                                 &cap);
>
> -               if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP)) {
> -                       vfio_pci_zap_and_down_write_memory_lock(vdev);
> -                       pci_try_reset_function(vdev->pdev);
> -                       up_write(&vdev->memory_lock);
> -               }
> +               if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP))
> +                       vfio_pci_try_reset_function(vdev);
>         }
>
>         return count;
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 4f1aceadd4fb..5904801f6f77 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -29,6 +29,8 @@
>
>  #include <linux/vfio_pci_core.h>
>
> +#include "vfio_pci_priv.h"
> +
>  #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
>  #define DRIVER_DESC "core driver for VFIO based PCI devices"
>
> @@ -648,6 +650,20 @@ int vfio_pci_register_dev_region(struct vfio_pci_core_device *vdev,
>  }
>  EXPORT_SYMBOL_GPL(vfio_pci_register_dev_region);
>
> +int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev)
> +{
> +       int ret;
> +
> +       if (!vdev->reset_works)
> +               return -EINVAL;
> +
> +       vfio_pci_zap_and_down_write_memory_lock(vdev);
> +       ret = pci_try_reset_function(vdev->pdev);
> +       up_write(&vdev->memory_lock);
> +
> +       return ret;
> +}
> +
>  long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
>                 unsigned long arg)
>  {
> @@ -929,30 +945,7 @@ long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
>                 return ret;
>
>         } else if (cmd == VFIO_DEVICE_RESET) {
> -               int ret;
> -
> -               if (!vdev->reset_works)
> -                       return -EINVAL;
> -
> -               vfio_pci_zap_and_down_write_memory_lock(vdev);
> -
> -               /*
> -                * This function can be invoked while the power state is non-D0.
> -                * If pci_try_reset_function() has been called while the power
> -                * state is non-D0, then pci_try_reset_function() will
> -                * internally set the power state to D0 without vfio driver
> -                * involvement. For the devices which have NoSoftRst-, the
> -                * reset function can cause the PCI config space reset without
> -                * restoring the original state (saved locally in
> -                * 'vdev->pm_save').
> -                */
> -               vfio_pci_set_power_state(vdev, PCI_D0);

The above call is missing from vfio_pci_try_reset_function(), is this
correct/intended?

--
Best regards,
Bartlomiej

> -
> -               ret = pci_try_reset_function(vdev->pdev);
> -               up_write(&vdev->memory_lock);
> -
> -               return ret;
> -
> +               return vfio_pci_try_reset_function(vdev);
>         } else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {
>                 struct vfio_pci_hot_reset_info hdr;
>                 struct vfio_pci_fill_info fill = { 0 };
> diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
> new file mode 100644
> index 000000000000..4971cd95b431
> --- /dev/null
> +++ b/drivers/vfio/pci/vfio_pci_priv.h
> @@ -0,0 +1,7 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef VFIO_PCI_PRIV_H
> +#define VFIO_PCI_PRIV_H
> +
> +int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev);
> +
> +#endif
William Tu Sept. 16, 2024, 2:36 p.m. UTC | #3 
Hi Bartlomiej,
I will add back the power management and send another version, thanks
William

From: William Tu <witu@nvidia.com>
Date: Wednesday, September 11, 2024 at 7:53 AM
To: Bartlomiej Zolnierkiewicz <bartlomiej.zolnierkiewicz@canonical.com>
Cc: kernel-team@lists.ubuntu.com <kernel-team@lists.ubuntu.com>, Vladimir Sokolovsky <vlad@nvidia.com>, Bodong Wang <bodong@nvidia.com>, Sergey Gorenko <sergeygo@nvidia.com>, Jason Gunthorpe <jgg@nvidia.com>, Ziv Waksman <zwaksman@nvidia.com>
Subject: Re: [SRU][J:linux-bluefield][PATCH v3 3/6] UBUNTU: SAUCE: vfio_pci: Do not open code pci_try_reset_function()
Hi Bartlomiej,

Thanks for your review!
Following the original patch
https://patchwork.kernel.org/project/linux-rdma/patch/3-v2-472615b3877e+28f7-vfio_dma_buf_jgg@nvidia.com/

The
               vfio_pci_set_power_state(vdev, PCI_D0);
is no longer needed, as it is done in
               pci_dev_save_and_disable

call trace is like
vfio_pci_try_reset_function
                pci_dev_save_and_disable
pci_set_power_state(dev, PCI_D0);

Thanks
William

From: Bartlomiej Zolnierkiewicz <bartlomiej.zolnierkiewicz@canonical.com>
Date: Wednesday, September 11, 2024 at 12:52 AM
To: William Tu <witu@nvidia.com>
Cc: kernel-team@lists.ubuntu.com <kernel-team@lists.ubuntu.com>, Vladimir Sokolovsky <vlad@nvidia.com>, Bodong Wang <bodong@nvidia.com>, Sergey Gorenko <sergeygo@nvidia.com>, Jason Gunthorpe <jgg@nvidia.com>, Ziv Waksman <zwaksman@nvidia.com>
Subject: Re: [SRU][J:linux-bluefield][PATCH v3 3/6] UBUNTU: SAUCE: vfio_pci: Do not open code pci_try_reset_function()
External email: Use caution opening links or attachments


On Fri, Sep 6, 2024 at 9:50 PM William Tu <witu@nvidia.com> wrote:
>
> From: Jason Gunthorpe <jgg@nvidia.com>
>
> BugLink: https://bugs.launchpad.net/bugs/2077887
>
> FLR triggered by an emulated config space write should not behave
> differently from a FLR triggered by VFIO_DEVICE_RESET, currently the
> config space path misses the power management.

After this patch all paths seem to miss the power management, please see below.

> Consolidate all the call sites to invoke a single function.
>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: William Tu <witu@nvidia.com>
> ---
>  drivers/vfio/pci/vfio_pci_config.c | 14 +++-------
>  drivers/vfio/pci/vfio_pci_core.c   | 41 +++++++++++++-----------------
>  drivers/vfio/pci/vfio_pci_priv.h   |  7 +++++
>  3 files changed, 28 insertions(+), 34 deletions(-)
>  create mode 100644 drivers/vfio/pci/vfio_pci_priv.h
>
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index 6e58b4bf7a60..78c626b8907d 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -857,11 +857,8 @@ static int vfio_exp_config_write(struct vfio_pci_core_device *vdev, int pos,
>                                                  pos - offset + PCI_EXP_DEVCAP,
>                                                  &cap);
>
> -               if (!ret && (cap & PCI_EXP_DEVCAP_FLR)) {
> -                       vfio_pci_zap_and_down_write_memory_lock(vdev);
> -                       pci_try_reset_function(vdev->pdev);
> -                       up_write(&vdev->memory_lock);
> -               }
> +               if (!ret && (cap & PCI_EXP_DEVCAP_FLR))
> +                       vfio_pci_try_reset_function(vdev);
>         }
>
>         /*
> @@ -939,11 +936,8 @@ static int vfio_af_config_write(struct vfio_pci_core_device *vdev, int pos,
>                                                 pos - offset + PCI_AF_CAP,
>                                                 &cap);
>
> -               if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP)) {
> -                       vfio_pci_zap_and_down_write_memory_lock(vdev);
> -                       pci_try_reset_function(vdev->pdev);
> -                       up_write(&vdev->memory_lock);
> -               }
> +               if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP))
> +                       vfio_pci_try_reset_function(vdev);
>         }
>
>         return count;
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 4f1aceadd4fb..5904801f6f77 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -29,6 +29,8 @@
>
>  #include <linux/vfio_pci_core.h>
>
> +#include "vfio_pci_priv.h"
> +
>  #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
>  #define DRIVER_DESC "core driver for VFIO based PCI devices"
>
> @@ -648,6 +650,20 @@ int vfio_pci_register_dev_region(struct vfio_pci_core_device *vdev,
>  }
>  EXPORT_SYMBOL_GPL(vfio_pci_register_dev_region);
>
> +int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev)
> +{
> +       int ret;
> +
> +       if (!vdev->reset_works)
> +               return -EINVAL;
> +
> +       vfio_pci_zap_and_down_write_memory_lock(vdev);
> +       ret = pci_try_reset_function(vdev->pdev);
> +       up_write(&vdev->memory_lock);
> +
> +       return ret;
> +}
> +
>  long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
>                 unsigned long arg)
>  {
> @@ -929,30 +945,7 @@ long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
>                 return ret;
>
>         } else if (cmd == VFIO_DEVICE_RESET) {
> -               int ret;
> -
> -               if (!vdev->reset_works)
> -                       return -EINVAL;
> -
> -               vfio_pci_zap_and_down_write_memory_lock(vdev);
> -
> -               /*
> -                * This function can be invoked while the power state is non-D0.
> -                * If pci_try_reset_function() has been called while the power
> -                * state is non-D0, then pci_try_reset_function() will
> -                * internally set the power state to D0 without vfio driver
> -                * involvement. For the devices which have NoSoftRst-, the
> -                * reset function can cause the PCI config space reset without
> -                * restoring the original state (saved locally in
> -                * 'vdev->pm_save').
> -                */
> -               vfio_pci_set_power_state(vdev, PCI_D0);

The above call is missing from vfio_pci_try_reset_function(), is this
correct/intended?

--
Best regards,
Bartlomiej

> -
> -               ret = pci_try_reset_function(vdev->pdev);
> -               up_write(&vdev->memory_lock);
> -
> -               return ret;
> -
> +               return vfio_pci_try_reset_function(vdev);
>         } else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {
>                 struct vfio_pci_hot_reset_info hdr;
>                 struct vfio_pci_fill_info fill = { 0 };
> diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
> new file mode 100644
> index 000000000000..4971cd95b431
> --- /dev/null
> +++ b/drivers/vfio/pci/vfio_pci_priv.h
> @@ -0,0 +1,7 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef VFIO_PCI_PRIV_H
> +#define VFIO_PCI_PRIV_H
> +
> +int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev);
> +
> +#endif
diff mbox series

Patch

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 6e58b4bf7a60..78c626b8907d 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -857,11 +857,8 @@  static int vfio_exp_config_write(struct vfio_pci_core_device *vdev, int pos,
 						 pos - offset + PCI_EXP_DEVCAP,
 						 &cap);
 
-		if (!ret && (cap & PCI_EXP_DEVCAP_FLR)) {
-			vfio_pci_zap_and_down_write_memory_lock(vdev);
-			pci_try_reset_function(vdev->pdev);
-			up_write(&vdev->memory_lock);
-		}
+		if (!ret && (cap & PCI_EXP_DEVCAP_FLR))
+			vfio_pci_try_reset_function(vdev);
 	}
 
 	/*
@@ -939,11 +936,8 @@  static int vfio_af_config_write(struct vfio_pci_core_device *vdev, int pos,
 						pos - offset + PCI_AF_CAP,
 						&cap);
 
-		if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP)) {
-			vfio_pci_zap_and_down_write_memory_lock(vdev);
-			pci_try_reset_function(vdev->pdev);
-			up_write(&vdev->memory_lock);
-		}
+		if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP))
+			vfio_pci_try_reset_function(vdev);
 	}
 
 	return count;
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 4f1aceadd4fb..5904801f6f77 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -29,6 +29,8 @@ 
 
 #include <linux/vfio_pci_core.h>
 
+#include "vfio_pci_priv.h"
+
 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
 #define DRIVER_DESC "core driver for VFIO based PCI devices"
 
@@ -648,6 +650,20 @@  int vfio_pci_register_dev_region(struct vfio_pci_core_device *vdev,
 }
 EXPORT_SYMBOL_GPL(vfio_pci_register_dev_region);
 
+int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev)
+{
+	int ret;
+
+	if (!vdev->reset_works)
+		return -EINVAL;
+
+	vfio_pci_zap_and_down_write_memory_lock(vdev);
+	ret = pci_try_reset_function(vdev->pdev);
+	up_write(&vdev->memory_lock);
+
+	return ret;
+}
+
 long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
 		unsigned long arg)
 {
@@ -929,30 +945,7 @@  long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
 		return ret;
 
 	} else if (cmd == VFIO_DEVICE_RESET) {
-		int ret;
-
-		if (!vdev->reset_works)
-			return -EINVAL;
-
-		vfio_pci_zap_and_down_write_memory_lock(vdev);
-
-		/*
-		 * This function can be invoked while the power state is non-D0.
-		 * If pci_try_reset_function() has been called while the power
-		 * state is non-D0, then pci_try_reset_function() will
-		 * internally set the power state to D0 without vfio driver
-		 * involvement. For the devices which have NoSoftRst-, the
-		 * reset function can cause the PCI config space reset without
-		 * restoring the original state (saved locally in
-		 * 'vdev->pm_save').
-		 */
-		vfio_pci_set_power_state(vdev, PCI_D0);
-
-		ret = pci_try_reset_function(vdev->pdev);
-		up_write(&vdev->memory_lock);
-
-		return ret;
-
+		return vfio_pci_try_reset_function(vdev);
 	} else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {
 		struct vfio_pci_hot_reset_info hdr;
 		struct vfio_pci_fill_info fill = { 0 };
diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
new file mode 100644
index 000000000000..4971cd95b431
--- /dev/null
+++ b/drivers/vfio/pci/vfio_pci_priv.h
@@ -0,0 +1,7 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef VFIO_PCI_PRIV_H
+#define VFIO_PCI_PRIV_H
+
+int vfio_pci_try_reset_function(struct vfio_pci_core_device *vdev);
+
+#endif