[PATCH V10 08/12] powerpc/powernv: Support EEH reset for VF PE
Wei Yang
weiyang at linux.vnet.ibm.com
Fri Oct 30 18:18:06 AEDT 2015
On Fri, Oct 30, 2015 at 03:11:20PM +1100, Alexey Kardashevskiy wrote:
>On 10/26/2015 02:15 PM, Wei Yang wrote:
>>PEs for VFs don't have primary bus. So they have to have their own reset
>>backend, which is used during EEH recovery. The patch implements the reset
>>backend for VF's PE by issuing FLR or AF FLR to the VFs, which are contained
>>in the PE.
>>
>>[gwshan: changelog and code refactoring]
>>Signed-off-by: Wei Yang <weiyang at linux.vnet.ibm.com>
>>Acked-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>>---
>> arch/powerpc/include/asm/eeh.h | 1 +
>> arch/powerpc/platforms/powernv/eeh-powernv.c | 134 ++++++++++++++++++++++++++-
>> 2 files changed, 134 insertions(+), 1 deletion(-)
>>
>>diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
>>index ec21f8f..331c856 100644
>>--- a/arch/powerpc/include/asm/eeh.h
>>+++ b/arch/powerpc/include/asm/eeh.h
>>@@ -136,6 +136,7 @@ struct eeh_dev {
>> int pcix_cap; /* Saved PCIx capability */
>> int pcie_cap; /* Saved PCIe capability */
>> int aer_cap; /* Saved AER capability */
>>+ int af_cap; /* Saved AF capability */
>> struct eeh_pe *pe; /* Associated PE */
>> struct list_head list; /* Form link list in the PE */
>> struct pci_controller *phb; /* Associated PHB */
>>diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
>>index cfd55dd..017cd72 100644
>>--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
>>+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
>>@@ -404,6 +404,7 @@ static void *pnv_eeh_probe(struct pci_dn *pdn, void *data)
>> edev->pcix_cap = pnv_eeh_find_cap(pdn, PCI_CAP_ID_PCIX);
>> edev->pcie_cap = pnv_eeh_find_cap(pdn, PCI_CAP_ID_EXP);
>> edev->aer_cap = pnv_eeh_find_ecap(pdn, PCI_EXT_CAP_ID_ERR);
>>+ edev->af_cap = pnv_eeh_find_cap(pdn, PCI_CAP_ID_AF);
>> if ((edev->class_code >> 8) == PCI_CLASS_BRIDGE_PCI) {
>> edev->mode |= EEH_DEV_BRIDGE;
>> if (edev->pcie_cap) {
>>@@ -893,6 +894,127 @@ static int pnv_eeh_bridge_reset(struct pci_dev *dev, int option)
>> return 0;
>> }
>>
>>+static void pnv_eeh_wait_for_pending(struct pci_dn *pdn, int pos,
>>+ u16 mask, bool af_flr_rst)
>>+{
>>+ struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
>>+ int status, i;
>>+
>>+ /* Wait for Transaction Pending bit to be cleared */
>>+ for (i = 0; i < 4; i++) {
>>+ eeh_ops->read_config(pdn, pos, 2, &status);
>
>
>gcc should have complained on using uninitialized @status here.
>
I remove the obj file and re-compile the file, not the warning.
And took a look at other places where read_config() is called. The laster
parameter is not initialized before called.
You see the error during build?
>
>>+ if (!(status & mask))
>>+ return;
>>+
>>+ msleep((1 << i) * 100);
>>+ }
>>+
>>+ pr_warn("%s: Pending transaction while issuing %s FLR to "
>>+ "%04x:%02x:%02x.%01x\n",
>
>Do not wrap user-visible strings.
>
Will change this.
>
>>+ __func__, af_flr_rst ? "AF" : "",
>>+ edev->phb->global_number, pdn->busno,
>>+ PCI_SLOT(pdn->devfn), PCI_FUNC(pdn->devfn));
>>+}
>>+
>>+static int pnv_eeh_do_flr(struct pci_dn *pdn, int option)
>>+{
>>+ struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
>>+ u32 reg;
>>+
>>+ if (!edev->pcie_cap)
>>+ return -ENOTTY;
>
>
>Can pnv_eeh_do_flr() be really called on a non PCIe device, can we get that
>far? WARN_ON_ONCE() may be?
>
So you suggest to add a WARN_ON_ONCE() in this condition, right?
>
>>+
>>+ eeh_ops->read_config(pdn, edev->pcie_cap + PCI_EXP_DEVCAP, 4, ®);
>
>
>... and here about uninitialized @reg.
>
>
>>+ if (!(reg & PCI_EXP_DEVCAP_FLR))
>>+ return -ENOTTY;
>>+
>>+ switch (option) {
>>+ case EEH_RESET_HOT:
>>+ case EEH_RESET_FUNDAMENTAL:
>>+ pnv_eeh_wait_for_pending(pdn, edev->pcie_cap + PCI_EXP_DEVSTA,
>>+ PCI_EXP_DEVSTA_TRPND, false);
>>+ eeh_ops->read_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
>>+ 4, ®);
>>+ reg |= PCI_EXP_DEVCTL_BCR_FLR;
>>+ eeh_ops->write_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
>>+ 4, reg);
>>+ msleep(EEH_PE_RST_HOLD_TIME);
>>+ break;
>>+ case EEH_RESET_DEACTIVATE:
>>+ eeh_ops->read_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
>>+ 4, ®);
>>+ reg &= ~PCI_EXP_DEVCTL_BCR_FLR;
>>+ eeh_ops->write_config(pdn, edev->pcie_cap + PCI_EXP_DEVCTL,
>>+ 4, reg);
>>+ msleep(EEH_PE_RST_SETTLE_TIME);
>>+ break;
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>>+static int pnv_eeh_do_af_flr(struct pci_dn *pdn, int option)
>>+{
>>+ struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
>>+ u32 cap;
>>+
>>+ if (!edev->af_cap)
>>+ return -ENOTTY;
>>+
>>+ eeh_ops->read_config(pdn, edev->af_cap + PCI_AF_CAP, 1, &cap);
>
>
>... and here about @cap.
>
>>+ if (!(cap & PCI_AF_CAP_TP) || !(cap & PCI_AF_CAP_FLR))
>>+ return -ENOTTY;
>>+
>>+ switch (option) {
>>+ case EEH_RESET_HOT:
>>+ case EEH_RESET_FUNDAMENTAL:
>>+ /*
>>+ * Wait for Transaction Pending bit to clear. A word-aligned
>>+ * test is used, so we use the conrol offset rather than status
>>+ * and shift the test bit to match.
>
>
>Why word-aligned (not byte or double word)?
>
I copied this words from pci_af_flr(). Actually, I don't tried to understand
this reason.
>>+ */
>>+ pnv_eeh_wait_for_pending(pdn, edev->af_cap + PCI_AF_CTRL,
>>+ PCI_AF_STATUS_TP << 8, true);
>>+ eeh_ops->write_config(pdn, edev->af_cap + PCI_AF_CTRL,
>>+ 1, PCI_AF_CTRL_FLR);
>>+ msleep(EEH_PE_RST_HOLD_TIME);
>>+ break;
>>+ case EEH_RESET_DEACTIVATE:
>>+ eeh_ops->write_config(pdn, edev->af_cap + PCI_AF_CTRL, 1, 0);
>>+ msleep(EEH_PE_RST_SETTLE_TIME);
>
>
>btw there is an unrelated issue with EEH_PE_RST_SETTLE_TIME which is defined
>as 1800 which is A LOT (+250ms from EEH_PE_RST_HOLD_TIME and for some reason
>this is actually doubled so there is another reset somewhere).
>
I don't know the reason for this value. This code keeps aligned with other
reset functions, like pnv_eeh_bridge_reset().
>Booting a guest with 63 VFs takes 6 minutes or so, is there a good reason for
>such a huge timeout?
>
>
>>+ break;
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>>+static int pnv_eeh_reset_vf(struct pci_dn *pdn, int option)
>>+{
>>+ int ret;
>>+
>>+ ret = pnv_eeh_do_flr(pdn, option);
>>+ if (ret != -ENOTTY)
>>+ return ret;
>>+
>>+ return pnv_eeh_do_af_flr(pdn, option);
>>+}
>>+
>>+static int pnv_eeh_vf_pe_reset(struct eeh_pe *pe, int option)
>>+{
>>+ struct eeh_dev *edev, *tmp;
>>+ struct pci_dn *pdn;
>>+ int ret;
>>+
>>+ eeh_pe_for_each_dev(pe, edev, tmp) {
>>+ pdn = eeh_dev_to_pdn(edev);
>>+ ret = pnv_eeh_reset_vf(pdn, option);
>>+ if (ret)
>>+ return ret;
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>> void pnv_pci_reset_secondary_bus(struct pci_dev *dev)
>> {
>> struct pci_controller *hose;
>>@@ -968,7 +1090,9 @@ static int pnv_eeh_reset(struct eeh_pe *pe, int option)
>> }
>>
>> bus = eeh_pe_bus_get(pe);
>>- if (pci_is_root_bus(bus) ||
>>+ if (pe->type & EEH_PE_VF)
>>+ ret = pnv_eeh_vf_pe_reset(pe, option);
>>+ else if (pci_is_root_bus(bus) ||
>> pci_is_root_bus(bus->parent))
>> ret = pnv_eeh_root_reset(hose, option);
>> else
>>@@ -1108,6 +1232,14 @@ static inline bool pnv_eeh_cfg_blocked(struct pci_dn *pdn)
>> if (!edev || !edev->pe)
>> return false;
>>
>>+ /*
>>+ * We will issue FLR or AF FLR to all VFs, which are contained
>>+ * in VF PE. It relies on the EEH PCI config accessors. So we
>>+ * can't block them during the window.
>>+ */
>>+ if ((edev->physfn) && (edev->pe->state & EEH_PE_RESET))
>
>
>Extra braces around edev->physfn.
>
Will remove it.
>
>
>>+ return false;
>>+
>> if (edev->pe->state & EEH_PE_CFG_BLOCKED)
>> return true;
>>
>>
>
>
>--
>Alexey
--
Richard Yang
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