Subject: Re: [PATCH V4 09/11] powerpc/eeh: handle VF PE properly

From: Gavin Shan <[email-masked]>
Date: Fri, 15 May 2015 17:31:16 +1000

On Fri, May 15, 2015 at 01:46:24PM +0800, Wei Yang wrote:
>Compared with Bus PE, VF PE just has one single pci function. This
>introduces the difference of error handling on a VF PE.
>
>For example in the hotplug case, EEH needs to remove and re-create the VF
>properly. In the case when PF's error_detected() disable SRIOV, this patch
>introduces a flag to mark the eeh_dev of a VF to avoid the slot_reset() and
>resume(). Since the FW is not ware of the VF, this patch handles the VF
>restore/reset in kernel directly.
>
>This patch is to handle the VF PE properly in these cases.
>
>Signed-off-by: Wei Yang <[email-masked]>

Acked-by: Gavin Shan <[email-masked]>

With following things fixed:

>---
> arch/powerpc/include/asm/eeh.h   |    1 +
> arch/powerpc/kernel/eeh.c        |    1 +
> arch/powerpc/kernel/eeh_driver.c |  103 ++++++++++++++++++++++++++++++--------
> arch/powerpc/kernel/eeh_pe.c     |    3 +-
> 4 files changed, 85 insertions(+), 23 deletions(-)
>
>diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
>index 3d64cf3..d24382c 100644
>--- a/arch/powerpc/include/asm/eeh.h
>+++ b/arch/powerpc/include/asm/eeh.h
>@@ -140,6 +140,7 @@ struct eeh_dev {
> 	struct pci_controller *phb;	/* Associated PHB		*/
> 	struct pci_dn *pdn;		/* Associated PCI device node	*/
> 	struct pci_dev *pdev;		/* Associated PCI device	*/
>+	int    in_error;		/* Error flag for eeh_dev	*/
> 	struct pci_dev *physfn;		/* Associated PF PORT		*/
> 	struct pci_bus *bus;		/* PCI bus for partial hotplug	*/
> };
>diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
>index 221e280..077c3d1 100644
>--- a/arch/powerpc/kernel/eeh.c
>+++ b/arch/powerpc/kernel/eeh.c
>@@ -1226,6 +1226,7 @@ void eeh_remove_device(struct pci_dev *dev)
> 	 * from the parent PE during the BAR resotre.
> 	 */
> 	edev->pdev = NULL;
>+	edev->in_error = 0;

Could you please put detailed comments aboug the the usage of "in_error" here?
I may look into it later to remove it. For now, you don't need to do that since
we're almost run out of time.

> 	dev->dev.archdata.edev = NULL;
> 	if (!(edev->pe->state & EEH_PE_KEEP))
> 		eeh_rmv_from_parent_pe(edev);
>diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
>index 89eb4bc..292089e 100644
>--- a/arch/powerpc/kernel/eeh_driver.c
>+++ b/arch/powerpc/kernel/eeh_driver.c
>@@ -211,6 +211,7 @@ static void *eeh_report_error(void *data, void *userdata)
> 	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> 	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
>
>+	edev->in_error = 1;
> 	eeh_pcid_put(dev);
> 	return NULL;
> }
>@@ -282,7 +283,8 @@ static void *eeh_report_reset(void *data, void *userdata)
>
> 	if (!driver->err_handler ||
> 	    !driver->err_handler->slot_reset ||
>-	    (edev->mode & EEH_DEV_NO_HANDLER)) {
>+	    (edev->mode & EEH_DEV_NO_HANDLER) ||
>+	    (!edev->in_error)) {
> 		eeh_pcid_put(dev);
> 		return NULL;
> 	}
>@@ -339,14 +341,16 @@ static void *eeh_report_resume(void *data, void *userdata)
>
> 	if (!driver->err_handler ||
> 	    !driver->err_handler->resume ||
>-	    (edev->mode & EEH_DEV_NO_HANDLER)) {
>+	    (edev->mode & EEH_DEV_NO_HANDLER) ||
>+	    (!edev->in_error)) {
> 		edev->mode &= ~EEH_DEV_NO_HANDLER;
>-		eeh_pcid_put(dev);
>-		return NULL;
>+		goto out;
> 	}
>
> 	driver->err_handler->resume(dev);
>
>+out:
>+	edev->in_error = 0;
> 	eeh_pcid_put(dev);
> 	return NULL;
> }
>@@ -386,12 +390,40 @@ static void *eeh_report_failure(void *data, void *userdata)
> 	return NULL;
> }
>
>+#ifdef CONFIG_PCI_IOV
>+static void *eeh_add_virt_device(void *data, void *userdata)
>+{
>+	struct pci_driver *driver;
>+	struct eeh_dev *edev = (struct eeh_dev *)data;
>+	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
>+	struct pci_dn *pdn = eeh_dev_to_pdn(edev);
>+
>+	if (!(edev->physfn)) {
>+		pr_warn("%s: EEH dev %04x:%02x:%02x:%01x not for VF\n",
>+			__func__, edev->phb->global_number, pdn->busno,
>+			PCI_SLOT(pdn->devfn), PCI_FUNC(pdn->devfn));

			    %04x:%02x:%02x.%01x

The connection symbol between device/function number is ".", not ":".

>+		return NULL;
>+	}
>+
>+	driver = eeh_pcid_get(dev);
>+	if (driver) {
>+		eeh_pcid_put(dev);
>+		if (driver->err_handler)
>+			return NULL;
>+	}
>+
>+	pci_iov_virtfn_add(edev->physfn, pdn->vf_index, 0);
>+	return NULL;
>+}
>+#endif /* CONFIG_PCI_IOV */
>+
> static void *eeh_rmv_device(void *data, void *userdata)
> {
> 	struct pci_driver *driver;
> 	struct eeh_dev *edev = (struct eeh_dev *)data;
> 	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
> 	int *removed = (int *)userdata;
>+	struct pci_dn *pdn = eeh_dev_to_pdn(edev);
>
> 	/*
> 	 * Actually, we should remove the PCI bridges as well.
>@@ -416,7 +448,7 @@ static void *eeh_rmv_device(void *data, void *userdata)
> 	driver = eeh_pcid_get(dev);
> 	if (driver) {
> 		eeh_pcid_put(dev);
>-		if (driver->err_handler)
>+		if (removed && driver->err_handler)
> 			return NULL;
> 	}
>
>@@ -425,11 +457,18 @@ static void *eeh_rmv_device(void *data, void *userdata)
> 		 pci_name(dev));
> 	edev->bus = dev->bus;
> 	edev->mode |= EEH_DEV_DISCONNECTED;
>-	(*removed)++;
>-
>-	pci_lock_rescan_remove();
>-	pci_stop_and_remove_bus_device(dev);
>-	pci_unlock_rescan_remove();
>+	if (removed)
>+		(*removed)++;
>+
>+	if (edev->physfn) {
>+		pci_iov_virtfn_remove(edev->physfn, pdn->vf_index, 0);
>+		edev->pdev = NULL;
>+		pdn->pe_number = IODA_INVALID_PE;
>+	} else {
>+		pci_lock_rescan_remove();
>+		pci_stop_and_remove_bus_device(dev);
>+		pci_unlock_rescan_remove();
>+	}
>
> 	return NULL;
> }
>@@ -548,6 +587,7 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
> 	struct pci_bus *frozen_bus = eeh_pe_bus_get(pe);
> 	struct timeval tstamp;
> 	int cnt, rc, removed = 0;
>+	struct eeh_dev *edev;
>
> 	/* pcibios will clear the counter; save the value */
> 	cnt = pe->freeze_count;
>@@ -561,12 +601,15 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
> 	 */
> 	eeh_pe_state_mark(pe, EEH_PE_KEEP);
> 	if (bus) {
>-		pci_lock_rescan_remove();
>-		pcibios_remove_pci_devices(bus);
>-		pci_unlock_rescan_remove();
>-	} else if (frozen_bus) {
>+		if (pe->type & EEH_PE_VF)
>+			eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
>+		else {
>+			pci_lock_rescan_remove();
>+			pcibios_remove_pci_devices(bus);
>+			pci_unlock_rescan_remove();
>+		}
>+	} else if (frozen_bus)
> 		eeh_pe_dev_traverse(pe, eeh_rmv_device, &removed);
>-	}
>
> 	/*
> 	 * Reset the pci controller. (Asserts RST#; resets config space).
>@@ -607,14 +650,26 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus)
> 		 * PE. We should disconnect it so the binding can be
> 		 * rebuilt when adding PCI devices.
> 		 */
>+		edev = list_first_entry(&pe->edevs, struct eeh_dev, list);
> 		eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
>-		pcibios_add_pci_devices(bus);
>+#ifdef CONFIG_PCI_IOV
>+		if (pe->type & EEH_PE_VF)
>+			eeh_add_virt_device(edev, NULL);
>+		else
>+#endif
>+			pcibios_add_pci_devices(bus);
> 	} else if (frozen_bus && removed) {
> 		pr_info("EEH: Sleep 5s ahead of partial hotplug\n");
> 		ssleep(5);
>
>+		edev = list_first_entry(&pe->edevs, struct eeh_dev, list);
> 		eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
>-		pcibios_add_pci_devices(frozen_bus);
>+#ifdef CONFIG_PCI_IOV
>+		if (pe->type & EEH_PE_VF)
>+			eeh_add_virt_device(edev, NULL);
>+		else
>+#endif
>+			pcibios_add_pci_devices(frozen_bus);
> 	}
> 	eeh_pe_state_clear(pe, EEH_PE_KEEP);
>
>@@ -792,11 +847,15 @@ perm_error:
> 	 * the their PCI config any more.
> 	 */
> 	if (frozen_bus) {
>-		eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
>-
>-		pci_lock_rescan_remove();
>-		pcibios_remove_pci_devices(frozen_bus);
>-		pci_unlock_rescan_remove();
>+		if (pe->type & EEH_PE_VF) {
>+			eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
>+			eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
>+		} else {
>+			eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
>+			pci_lock_rescan_remove();
>+			pcibios_remove_pci_devices(frozen_bus);
>+			pci_unlock_rescan_remove();
>+		}
> 	}
> }
>
>diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
>index 260a701..5cde950 100644
>--- a/arch/powerpc/kernel/eeh_pe.c
>+++ b/arch/powerpc/kernel/eeh_pe.c
>@@ -914,7 +914,8 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
> 	if (pe->type & EEH_PE_PHB) {
> 		bus = pe->phb->bus;
> 	} else if (pe->type & EEH_PE_BUS ||
>-		   pe->type & EEH_PE_DEVICE) {
>+		   pe->type & EEH_PE_DEVICE ||
>+		   pe->type & EEH_PE_VF) {
> 		if (pe->bus) {
> 			bus = pe->bus;
> 			goto out;
>-- 
>1.7.9.5
>