Re: [PATCH 2/2] PCI: Save properties required to handle FLR for replay purposes.

["Raj, Ashok" <ashok.raj@intel.com>]

On Tue, May 30, 2017 at 02:50:33PM -0500, Bjorn Helgaas wrote:
> On Tue, May 30, 2017 at 09:25:49AM -0700, Ashok Raj wrote:
> > From: CQ Tang <cq.tang@intel.com>
> > 
> > Requires: https://patchwork.kernel.org/patch/9593891
> 
> The above patch (9593891) is not in my tree or Linus' tree, so I can't
> do anything with this yet.

I resent the patch as part of this series.. maybe should have massaged the 
commit message.. my bad :-(. Its the first patch in this series.

Jean mentioned it might take him a while before the SVM patches stabilize.
Since this patch is pretty much stand alone, he asked if i could resend it
along with the one i need.

Sorry for any confusion.

Cheers,
Ashok
> 
> > After a FLR, pci-states need to be restored. This patch saves PASID features
> > and PRI reqs cached.
> > 
> > To: Bjorn Helgaas <bhelgaas@google.com>
> > To: Joerg Roedel <joro@8bytes.org>
> > To: linux-pci@vger.kernel.org
> > To: linux-kernel@vger.kernel.org
> > Cc: Jean-Phillipe Brucker <jean-philippe.brucker@arm.com>
> > Cc: David Woodhouse <dwmw2@infradead.org>
> > Cc: iommu@lists.linux-foundation.org
> > 
> > Signed-off-by: CQ Tang <cq.tang@intel.com>
> > Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> > ---
> >  drivers/pci/ats.c       | 65 +++++++++++++++++++++++++++++++++++++------------
> >  drivers/pci/pci.c       |  3 +++
> >  include/linux/pci-ats.h | 10 ++++++++
> >  include/linux/pci.h     |  6 +++++
> >  4 files changed, 69 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> > index 2126497..a769955 100644
> > --- a/drivers/pci/ats.c
> > +++ b/drivers/pci/ats.c
> > @@ -160,17 +160,16 @@ int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
> >  	if (!pos)
> >  		return -EINVAL;
> >  
> > -	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
> >  	pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
> > -	if ((control & PCI_PRI_CTRL_ENABLE) ||
> > -	    !(status & PCI_PRI_STATUS_STOPPED))
> > +	if (!(status & PCI_PRI_STATUS_STOPPED))
> >  		return -EBUSY;
> >  
> >  	pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
> >  	reqs = min(max_requests, reqs);
> > +	pdev->pri_reqs_alloc = reqs;
> >  	pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
> >  
> > -	control |= PCI_PRI_CTRL_ENABLE;
> > +	control = PCI_PRI_CTRL_ENABLE;
> >  	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
> >  
> >  	pdev->pri_enabled = 1;
> > @@ -206,6 +205,29 @@ void pci_disable_pri(struct pci_dev *pdev)
> >  EXPORT_SYMBOL_GPL(pci_disable_pri);
> >  
> >  /**
> > + * pci_restore_pri_state - Restore PRI
> > + * @pdev: PCI device structure
> > + *
> > + */
> > +void pci_restore_pri_state(struct pci_dev *pdev)
> > +{
> > +   u16 control = PCI_PRI_CTRL_ENABLE;
> > +   u32 reqs = pdev->pri_reqs_alloc;
> > +   int pos;
> > +
> > +   pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
> > +   if (!pos)
> > +       return;
> > +
> > +   if (!pdev->pri_enabled)
> > +       return;
> > +
> > +   pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
> > +   pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
> > +}
> > +EXPORT_SYMBOL_GPL(pci_restore_pri_state);
> > +
> > +/**
> >   * pci_reset_pri - Resets device's PRI state
> >   * @pdev: PCI device structure
> >   *
> > @@ -224,12 +246,7 @@ int pci_reset_pri(struct pci_dev *pdev)
> >  	if (!pos)
> >  		return -EINVAL;
> >  
> > -	pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
> > -	if (control & PCI_PRI_CTRL_ENABLE)
> > -		return -EBUSY;
> > -
> > -	control |= PCI_PRI_CTRL_RESET;
> > -
> > +	control = PCI_PRI_CTRL_RESET;
> >  	pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
> >  
> >  	return 0;
> > @@ -259,12 +276,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
> >  	if (!pos)
> >  		return -EINVAL;
> >  
> > -	pci_read_config_word(pdev, pos + PCI_PASID_CTRL, &control);
> >  	pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
> > -
> > -	if (control & PCI_PASID_CTRL_ENABLE)
> > -		return -EINVAL;
> > -
> >  	supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
> >  
> >  	/* User wants to enable anything unsupported? */
> > @@ -272,6 +284,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
> >  		return -EINVAL;
> >  
> >  	control = PCI_PASID_CTRL_ENABLE | features;
> > +	pdev->pasid_features = features;
> >  
> >  	pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
> >  
> > @@ -305,6 +318,28 @@ void pci_disable_pasid(struct pci_dev *pdev)
> >  EXPORT_SYMBOL_GPL(pci_disable_pasid);
> >  
> >  /**
> > + * pci_restore_pasid_state - Restore PASID capabilities.
> > + * @pdev: PCI device structure
> > + *
> > + */
> > +void pci_restore_pasid_state(struct pci_dev *pdev)
> > +{
> > +   u16 control;
> > +   int pos;
> > +
> > +   pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
> > +   if (!pos)
> > +       return;
> > +
> > +   if (!pdev->pasid_enabled)
> > +       return;
> > +
> > +   control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
> > +   pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
> > +}
> > +EXPORT_SYMBOL_GPL(pci_restore_pasid_state);
> > +
> > +/**
> >   * pci_pasid_features - Check which PASID features are supported
> >   * @pdev: PCI device structure
> >   *
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 7904d02..c9a6510 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -28,6 +28,7 @@
> >  #include <linux/pm_runtime.h>
> >  #include <linux/pci_hotplug.h>
> >  #include <linux/vmalloc.h>
> > +#include <linux/pci-ats.h>
> >  #include <asm/setup.h>
> >  #include <asm/dma.h>
> >  #include <linux/aer.h>
> > @@ -1171,6 +1172,8 @@ void pci_restore_state(struct pci_dev *dev)
> >  
> >  	/* PCI Express register must be restored first */
> >  	pci_restore_pcie_state(dev);
> > +	pci_restore_pasid_state(dev);
> > +	pci_restore_pri_state(dev);
> >  	pci_restore_ats_state(dev);
> >  	pci_restore_vc_state(dev);
> >  
> > diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
> > index 57e0b82..782fb8e 100644
> > --- a/include/linux/pci-ats.h
> > +++ b/include/linux/pci-ats.h
> > @@ -7,6 +7,7 @@
> >  
> >  int pci_enable_pri(struct pci_dev *pdev, u32 reqs);
> >  void pci_disable_pri(struct pci_dev *pdev);
> > +void pci_restore_pri_state(struct pci_dev *pdev);
> >  int pci_reset_pri(struct pci_dev *pdev);
> >  
> >  #else /* CONFIG_PCI_PRI */
> > @@ -20,6 +21,10 @@ static inline void pci_disable_pri(struct pci_dev *pdev)
> >  {
> >  }
> >  
> > +static inline void pci_restore_pri_state(struct pci_dev *pdev)
> > +{
> > +}
> > +
> >  static inline int pci_reset_pri(struct pci_dev *pdev)
> >  {
> >  	return -ENODEV;
> > @@ -31,6 +36,7 @@ static inline int pci_reset_pri(struct pci_dev *pdev)
> >  
> >  int pci_enable_pasid(struct pci_dev *pdev, int features);
> >  void pci_disable_pasid(struct pci_dev *pdev);
> > +void pci_restore_pasid_state(struct pci_dev *pdev);
> >  int pci_pasid_features(struct pci_dev *pdev);
> >  int pci_max_pasids(struct pci_dev *pdev);
> >  
> > @@ -45,6 +51,10 @@ static inline void pci_disable_pasid(struct pci_dev *pdev)
> >  {
> >  }
> >  
> > +static inline void pci_restore_pasid_state(struct pci_dev *pdev)
> > +{
> > +}
> > +
> >  static inline int pci_pasid_features(struct pci_dev *pdev)
> >  {
> >  	return -EINVAL;
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index bee980e..1ddb8e0 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -395,6 +395,12 @@ struct pci_dev {
> >  	u8		ats_stu;	/* ATS Smallest Translation Unit */
> >  	atomic_t	ats_ref_cnt;	/* number of VFs with ATS enabled */
> >  #endif
> > +#ifdef CONFIG_PCI_PRI
> > +	u32		pri_reqs_alloc; /* Number of PRI requests allocated */
> > +#endif
> > +#ifdef CONFIG_PCI_PASID
> > +	u16		pasid_features;
> > +#endif
> >  	phys_addr_t rom; /* Physical address of ROM if it's not from the BAR */
> >  	size_t romlen; /* Length of ROM if it's not from the BAR */
> >  	char *driver_override; /* Driver name to force a match */
> > -- 
> > 2.7.4
> >