On Sat, 2020-10-17 at 09:14 -0700, Sean V Kelley wrote: > On 16 Oct 2020, at 13:30, Bjorn Helgaas wrote: > > > [+to Jonathan] > > > > On Thu, Oct 15, 2020 at 05:11:10PM -0700, Sean V Kelley wrote: > > > From: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx> > > > > > > When attempting error recovery for an RCiEP associated with an > > > RCEC > > > device, > > > there needs to be a way to update the Root Error Status, the > > > Uncorrectable > > > Error Status and the Uncorrectable Error Severity of the parent > > > RCEC. > > > In > > > some non-native cases in which there is no OS-visible device > > > associated > > > with the RCiEP, there is nothing to act upon as the firmware is > > > acting > > > before the OS. > > > > > > Add handling for the linked RCEC in AER/ERR while taking into > > > account > > > non-native cases. > > > > > > Co-developed-by: Sean V Kelley <sean.v.kelley@xxxxxxxxx> > > > Link: > > > https://lore.kernel.org/r/20201002184735.1229220-12-seanvk.dev@xxxxxxxxxxxxxxxx > > > Signed-off-by: Sean V Kelley <sean.v.kelley@xxxxxxxxx> > > > Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx> > > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > --- > > > drivers/pci/pcie/aer.c | 53 > > > ++++++++++++++++++++++++++++++------------ > > > drivers/pci/pcie/err.c | 20 ++++++++-------- > > > 2 files changed, 48 insertions(+), 25 deletions(-) > > > > > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > > > index 65dff5f3457a..083f69b67bfd 100644 > > > --- a/drivers/pci/pcie/aer.c > > > +++ b/drivers/pci/pcie/aer.c > > > @@ -1357,27 +1357,50 @@ static int aer_probe(struct pcie_device > > > *dev) > > > */ > > > static pci_ers_result_t aer_root_reset(struct pci_dev *dev) > > > { > > > - int aer = dev->aer_cap; > > > + int type = pci_pcie_type(dev); > > > + struct pci_dev *root; > > > + int aer = 0; > > > + int rc = 0; > > > u32 reg32; > > > - int rc; > > > > > > + if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) > > > > "type == PCI_EXP_TYPE_RC_END" > > Right, I merged your suggested changes which added the type. Will > correct. > > > > > > + /* > > > + * The reset should only clear the Root Error > > > Status > > > + * of the RCEC. Only perform this for the > > > + * native case, i.e., an RCEC is present. > > > + */ > > > + root = dev->rcec; > > > + else > > > + root = dev; > > > > > > - /* Disable Root's interrupt in response to error messages > > > */ > > > - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, > > > ®32); > > > - reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK; > > > - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, > > > reg32); > > > + if (root) > > > + aer = dev->aer_cap; > > > > > > - rc = pci_bus_error_reset(dev); > > > - pci_info(dev, "Root Port link has been reset\n"); > > > + if (aer) { > > > + /* Disable Root's interrupt in response to error > > > messages */ > > > + pci_read_config_dword(root, aer + > > > PCI_ERR_ROOT_COMMAND, ®32); > > > + reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK; > > > + pci_write_config_dword(root, aer + > > > PCI_ERR_ROOT_COMMAND, reg32); > > > > Not directly related to *this* patch, but my assumption was that in > > the APEI case, the firmware should retain ownership of the AER > > Capability, so the OS should not touch PCI_ERR_ROOT_COMMAND and > > PCI_ERR_ROOT_STATUS. > > > > But this code appears to ignore that ownership. Jonathan, you must > > have looked at this recently for 068c29a248b6 ("PCI/ERR: Clear PCIe > > Device Status errors only if OS owns AER"). Do you have any > > insight > > about this? > > > > > - /* Clear Root Error Status */ > > > - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, > > > ®32); > > > - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, > > > reg32); > > > + /* Clear Root Error Status */ > > > + pci_read_config_dword(root, aer + > > > PCI_ERR_ROOT_STATUS, ®32); > > > + pci_write_config_dword(root, aer + > > > PCI_ERR_ROOT_STATUS, reg32); > > > > > > - /* Enable Root Port's interrupt in response to error > > > messages */ > > > - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, > > > ®32); > > > - reg32 |= ROOT_PORT_INTR_ON_MESG_MASK; > > > - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, > > > reg32); > > > + /* Enable Root Port's interrupt in response to > > > error messages */ > > > + pci_read_config_dword(root, aer + > > > PCI_ERR_ROOT_COMMAND, ®32); > > > + reg32 |= ROOT_PORT_INTR_ON_MESG_MASK; > > > + pci_write_config_dword(root, aer + > > > PCI_ERR_ROOT_COMMAND, reg32); > > > + } > > > + > > > + if ((type == PCI_EXP_TYPE_RC_EC) || (type == > > > PCI_EXP_TYPE_RC_END)) > > > { > > > + if (pcie_has_flr(root)) { > > > + rc = pcie_flr(root); > > > + pci_info(dev, "has been reset (%d)\n", > > > rc); > > > + } > > > + } else { > > > + rc = pci_bus_error_reset(root); > > > > Don't we want "dev" for both the FLR and pci_bus_error_reset()? I > > think "root == dev" except when dev is an RCiEP. When dev is an > > RCiEP, "root" is the RCEC (if present), and we want to reset the > > RCiEP, not the RCEC. > > Right, when I did the goto in the earlier incarnation, I always set > root > to dev at the start and in the merge it needs to be dev always except > for the RC_END where RCEC exists. Will change without bringing back > the > goto… > > + struct pci_dev *root = dev; > > … > > +non_native: > + if ((type == PCI_EXP_TYPE_RC_EC) || (type == > PCI_EXP_TYPE_RC_END)) { > + rc = flr_on_rc(root); > + pci_info(dev, "has been reset (%d)\n", rc); > + } else { > + rc = pci_bus_error_reset(root); > + pci_info(dev, "Root Port link has been reset (%d)\n", > rc); > + } > > > > > > > + pci_info(dev, "Root Port link has been reset > > > (%d)\n", rc); > > > + } > > > > There are a couple changes here that I think should be split out. > > > > Based on my theory that when firmware retains control of AER, the > > OS > > should not touch PCI_ERR_ROOT_COMMAND and PCI_ERR_ROOT_STATUS, and > > any > > updates to them would have to be done by firmware before we get > > here, > > I suggested reordering this: > > > > - clear PCI_ERR_ROOT_COMMAND ROOT_PORT_INTR_ON_MESG_MASK > > - do reset > > - clear PCI_ERR_ROOT_STATUS (for APEI, presumably done by > > firmware?) > > - enable PCI_ERR_ROOT_COMMAND ROOT_PORT_INTR_ON_MESG_MASK > > > > to this: > > > > - clear PCI_ERR_ROOT_COMMAND ROOT_PORT_INTR_ON_MESG_MASK > > - clear PCI_ERR_ROOT_STATUS > > - enable PCI_ERR_ROOT_COMMAND ROOT_PORT_INTR_ON_MESG_MASK > > - do reset > > > > If my theory is correct, I think we should still reorder this, but: > > > > - It's a significant behavior change that deserves its own patch > > so > > we can document/bisect/revert. > > > > - I'm not sure why we clear the PCI_ERR_ROOT_COMMAND error > > reporting > > bits. In the new "clear COMMAND, clear STATUS, enable COMMAND" > > order, it looks superfluous. There's no reason to disable > > error > > reporting while clearing the status bits. > > > > The current "clear, reset, enable" order suggests that the > > reset > > might cause errors that we should ignore. I don't know whether > > that's the case or not. It dates from 6c2b374d7485 ("PCI- > > Express > > AER implemetation: AER core and aerdriver"), which doesn't > > elaborate. > > > > - Should we also test for OS ownership of AER before touching > > PCI_ERR_ROOT_STATUS? > > > > - If we remove the PCI_ERR_ROOT_COMMAND fiddling (and I > > tentatively > > think we *should* unless we can justify it), that would also > > deserve its own patch. Possibly (1) remove > > PCI_ERR_ROOT_COMMAND > > fiddling, (2) reorder PCI_ERR_ROOT_STATUS clearing and reset, > > (3) > > test for OS ownership of AER (?), (4) the rest of this patch. > > You’ve highlighted some good questions. Reading Ethan's reply and also thinking about separation from an _OSC perspective perhaps something like this could be done with a check in aer_root_reset(). diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c index 65dff5f3457a..70bf637042ff 100644 --- a/drivers/pci/pcie/aer.c +++ b/drivers/pci/pcie/aer.c @@ -1357,27 +1357,46 @@ static int aer_probe(struct pcie_device *dev) */ static pci_ers_result_t aer_root_reset(struct pci_dev *dev) { + int type = pci_pcie_type(dev); + struct pci_dev *root = dev; int aer = dev->aer_cap; + int rc = 0; u32 reg32; - int rc; + if (!pcie_aer_is_native(dev)) + return PCI_ERS_RESULT_RECOVERD; + + if (type == PCI_EXP_TYPE_RC_END) + /* + * The reset should only clear the Root Error Status + * of the RCEC. Only perform this for the + * native case, i.e., an RCEC is present. + */ + root = dev->rcec; /* Disable Root's interrupt in response to error messages */ - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, ®32); + pci_read_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, ®32); reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK; - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32); - - rc = pci_bus_error_reset(dev); - pci_info(dev, "Root Port link has been reset\n"); + pci_write_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, reg32); /* Clear Root Error Status */ - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, ®32); - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, reg32); + pci_read_config_dword(root, aer + PCI_ERR_ROOT_STATUS, ®32); + pci_write_config_dword(root, aer + PCI_ERR_ROOT_STATUS, reg32); /* Enable Root Port's interrupt in response to error messages */ - pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, ®32); + pci_read_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, ®32); reg32 |= ROOT_PORT_INTR_ON_MESG_MASK; - pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32); + pci_write_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, reg32); + + if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) { + if (pcie_has_flr(dev)) { + rc = pcie_flr(dev); + pci_info(dev, "has been reset (%d)\n", rc); + } + } else { + rc = pci_bus_error_reset(dev); + pci_info(dev, "Root Port link has been reset (%d)\n", rc); + } > > I think we should remove the fiddling until we have a clearer picture > and put that into its own patch. > > Sean > > > > > return rc ? PCI_ERS_RESULT_DISCONNECT : > > > PCI_ERS_RESULT_RECOVERED; > > > } > > > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c > > > index 7883c9791562..cbc5abfe767b 100644 > > > --- a/drivers/pci/pcie/err.c > > > +++ b/drivers/pci/pcie/err.c > > > @@ -148,10 +148,10 @@ static int report_resume(struct pci_dev > > > *dev, > > > void *data) > > > > > > /** > > > * pci_walk_bridge - walk bridges potentially AER affected > > > - * @bridge: bridge which may be a Port, an RCEC with > > > associated > > > RCiEPs, > > > - * or an RCiEP associated with an RCEC > > > - * @cb: callback to be called for each device > > > found > > > - * @userdata: arbitrary pointer to be passed to callback > > > + * @bridge bridge which may be an RCEC with associated RCiEPs, > > > + * or a Port. > > > + * @cb callback to be called for each device found > > > + * @userdata arbitrary pointer to be passed to callback. > > > * > > > * If the device provided is a bridge, walk the subordinate bus, > > > including > > > * any bridged devices on buses under this bus. Call the > > > provided > > > callback > > > @@ -164,8 +164,14 @@ static void pci_walk_bridge(struct pci_dev > > > *bridge, > > > int (*cb)(struct pci_dev *, void *), > > > void *userdata) > > > { > > > + /* > > > + * In a non-native case where there is no OS-visible > > > reporting > > > + * device the bridge will be NULL, i.e., no RCEC, no > > > Downstream > > > Port. > > > + */ > > > if (bridge->subordinate) > > > pci_walk_bus(bridge->subordinate, cb, userdata); > > > + else if (bridge->rcec) > > > + cb(bridge->rcec, userdata); > > > else > > > cb(bridge, userdata); > > > } > > > @@ -194,12 +200,6 @@ pci_ers_result_t pcie_do_recovery(struct > > > pci_dev > > > *dev, > > > pci_dbg(bridge, "broadcast error_detected message\n"); > > > if (state == pci_channel_io_frozen) { > > > pci_walk_bridge(bridge, report_frozen_detected, > > > &status); > > > - if (type == PCI_EXP_TYPE_RC_END) { > > > - pci_warn(dev, "subordinate device reset > > > not possible for > > > RCiEP\n"); > > > - status = PCI_ERS_RESULT_NONE; > > > - goto failed; > > > - } > > > - > > > status = reset_subordinates(bridge); > > > if (status != PCI_ERS_RESULT_RECOVERED) { > > > pci_warn(bridge, "subordinate device > > > reset failed\n"); > > > -- > > > 2.28.0 > > >
