[PATCH] pcie: Restore ACS configuration as part of pci_restore_state

[PATCH] pcie: Restore ACS configuration as part of pci_restore_state

[Alexander Duyck]

This change is meant to address the fact that ACS state was not being
restored as a part of the PCI configuration restoration following a PCIe
reset.  Without this patch it is not possible to reassign interfaces behind
ACS enabled switches following a system suspend as all of the ACS
functionality is disabled due to the D0->D3->D0 state transition cycle
clearing the configuration state and the fact that the ACS logic was only
initialized in probe.

Cc: Allen Kay <allen.m.kay@intel.com>
Cc: Chris Wright <chris@sous-sol.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 drivers/pci/pci.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0008c950452c..9bd9526f3388 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1092,6 +1092,9 @@ void pci_restore_state(struct pci_dev *dev)
 
 	pci_restore_pcix_state(dev);
 	pci_restore_msi_state(dev);
+
+	/* Restore ACS and IOV configuration state */
+	pci_enable_acs(dev);
 	pci_restore_iov_state(dev);
 
 	dev->state_saved = false;

Re: [PATCH] pcie: Restore ACS configuration as part of pci_restore_state

[Bjorn Helgaas]

On Tue, Jul 07, 2015 at 12:24:35PM -0700, Alexander Duyck wrote:
> This change is meant to address the fact that ACS state was not being
> restored as a part of the PCI configuration restoration following a PCIe
> reset.  Without this patch it is not possible to reassign interfaces behind
> ACS enabled switches following a system suspend as all of the ACS
> functionality is disabled due to the D0->D3->D0 state transition cycle
> clearing the configuration state and the fact that the ACS logic was only
> initialized in probe.
> 
> Cc: Allen Kay <allen.m.kay@intel.com>
> Cc: Chris Wright <chris@sous-sol.org>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>

Applied to pci/virtualization for v4.3 with changelog as follows, thanks!

commit ccbc175aad819e1d4b6af6246b12d55b13d97815
Author: Alexander Duyck <alexander.h.duyck@redhat.com>
Date:   Tue Jul 7 12:24:35 2015 -0700

    PCI: Restore ACS configuration as part of pci_restore_state()
    
    Previously we did not restore ACS state after a PCIe reset.  This meant
    that we could not reassign interfaces after a system suspend because the
    D0->D3 transition disabled ACS, and we didn't restore it when going back to
    D0.
    
    Restore ACS configuration in pci_restore_state().
    
    [bhelgaas: changelog]
    Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    CC: Allen Kay <allen.m.kay@intel.com>
    CC: Chris Wright <chris@sous-sol.org>
    CC: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0008c95..9bd9526f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1092,6 +1092,9 @@ void pci_restore_state(struct pci_dev *dev)
 
 	pci_restore_pcix_state(dev);
 	pci_restore_msi_state(dev);
+
+	/* Restore ACS and IOV configuration state */
+	pci_enable_acs(dev);
 	pci_restore_iov_state(dev);
 
 	dev->state_saved = false;