On Wed, 2 Dec 2020 17:18:12 +0800 Chiqijun <chiqijun@xxxxxxxxxx> wrote: > On 2020/11/30 23:46, Alex Williamson wrote: > > On Sat, 28 Nov 2020 17:29:19 -0600 > > Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > >> [+cc Alex] > >> > >> On Sat, Nov 28, 2020 at 02:18:25PM +0800, Chiqijun wrote: > >>> When multiple VFs do FLR at the same time, the firmware is > >>> processed serially, resulting in some VF FLRs being delayed more > >>> than 100ms, when the virtual machine restarts and the device > >>> driver is loaded, the firmware is doing the corresponding VF > >>> FLR, causing the driver to fail to load. > >>> > >>> To solve this problem, add host and firmware status synchronization > >>> during FLR. > >> > >> Is this because the Huawei Intelligent NIC isn't following the spec, > >> or is it because Linux isn't correctly waiting for the FLR to > >> complete? > > > > Seems like a spec compliance issue, I don't recall anything in the spec > > about coordinating FLR between VFs. > > The spec stipulates that the FLR time of a single VF does not exceed > 100ms, but when multiple VMs are reset concurrently in Linux, there will > be multiple VF parallel FLRs, VF of Huawei Intelligent NIC > FLR will exceed 100ms in this case. > > > > >> If this is a Huawei Intelligent NIC defect, is there documentation > >> somewhere (errata) that you can reference? Will it be fixed in future > >> designs, so we don't have to add future Device IDs to the quirk? > >> > >>> Signed-off-by: Chiqijun <chiqijun@xxxxxxxxxx> > >>> --- > >>> drivers/pci/quirks.c | 67 ++++++++++++++++++++++++++++++++++++++++++++ > >>> 1 file changed, 67 insertions(+) > >>> > >>> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > >>> index f70692ac79c5..bd6236ea9064 100644 > >>> --- a/drivers/pci/quirks.c > >>> +++ b/drivers/pci/quirks.c > >>> @@ -3912,6 +3912,71 @@ static int delay_250ms_after_flr(struct pci_dev *dev, int probe) > >>> return 0; > >>> } > >>> > >>> +#define PCI_DEVICE_ID_HINIC_VF 0x375E > >>> +#define HINIC_VF_FLR_TYPE 0x1000 > >>> +#define HINIC_VF_OP 0xE80 > >>> +#define HINIC_OPERATION_TIMEOUT 15000 > >>> + > >>> +/* Device-specific reset method for Huawei Intelligent NIC virtual functions */ > >>> +static int reset_hinic_vf_dev(struct pci_dev *pdev, int probe) > >>> +{ > >>> + unsigned long timeout; > >>> + void __iomem *bar; > >>> + u16 old_command; > >>> + u32 val; > >>> + > >>> + if (probe) > >>> + return 0; > >>> + > >>> + bar = pci_iomap(pdev, 0, 0); > >>> + if (!bar) > >>> + return -ENOTTY; > >>> + > >>> + pci_read_config_word(pdev, PCI_COMMAND, &old_command); > >>> + > >>> + /* > >>> + * FLR cap bit bit30, FLR ACK bit: bit18, to avoid big-endian conversion > >>> + * the big-endian bit6, bit10 is directly operated here > >>> + */ > >>> + val = readl(bar + HINIC_VF_FLR_TYPE); > >>> + if (!(val & (1UL << 6))) { > >>> + pci_iounmap(pdev, bar); > >>> + return -ENOTTY; > >>> + } > > > > > > I don't know exactly what this is testing, but it seems like a > > feature/capability test that can fail, why is it not done as part of > > the probe? Can we define bit 6 with a macro? Same for bit 10 in the > > VF op register below. > > The firmware of Huawei Intelligent NIC does not support this feature in > the old version. here is the reading ability to determine whether the > firmware supports it. > In the next patch, I will add a comment here and replace bit 6 and bit > 10 with macro definitions. The question remains why this is not done as part of the probe. If the device firmware doesn't support it, isn't it better to try a regular FLR and have it return error if the time is exceeded rather than claim we have a functional device specific reset quirk that will always fail without ever attempting to FLR the VF? Thanks, Alex > >>> + > >>> + val = readl(bar + HINIC_VF_OP); > >>> + val = val | (1UL << 10); > >>> + writel(val, bar + HINIC_VF_OP); > >>> + > >>> + /* Perform the actual device function reset */ > >>> + pcie_flr(pdev); > >>> + > >>> + pci_write_config_word(pdev, PCI_COMMAND, > >>> + old_command | PCI_COMMAND_MEMORY); > >>> + > >>> + /* Waiting for device reset complete */ > >>> + timeout = jiffies + msecs_to_jiffies(HINIC_OPERATION_TIMEOUT); > > > > Yikes, 15s timeout! > > Huawei Intelligent NIC supports a maximum of 496 VFs, so the total > timeout period is set to 15s, which will not reach the timeout time > under normal circumstances. > > > > >>> + do { > >>> + val = readl(bar + HINIC_VF_OP); > >>> + if (!(val & (1UL << 10))) > >>> + goto reset_complete; > >>> + msleep(20); > >>> + } while (time_before(jiffies, timeout)); > >>> + > >>> + val = readl(bar + HINIC_VF_OP); > >>> + if (!(val & (1UL << 10))) > >>> + goto reset_complete; > >>> + > >>> + pci_warn(pdev, "Reset dev timeout, flr ack reg: %x\n", > >>> + be32_to_cpu(val)); > >>> + > >>> +reset_complete: > >>> + pci_write_config_word(pdev, PCI_COMMAND, old_command); > >>> + pci_iounmap(pdev, bar); > >>> + > >>> + return 0; > >>> +} > >>> + > >>> static const struct pci_dev_reset_methods pci_dev_reset_methods[] = { > >>> { PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF, > >>> reset_intel_82599_sfp_virtfn }, > >>> @@ -3923,6 +3988,8 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = { > >>> { PCI_VENDOR_ID_INTEL, 0x0953, delay_250ms_after_flr }, > >>> { PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID, > >>> reset_chelsio_generic_dev }, > >>> + { PCI_VENDOR_ID_HUAWEI, PCI_DEVICE_ID_HINIC_VF, > >>> + reset_hinic_vf_dev }, > >>> { 0 } > >>> }; > >>> > >>> -- > >>> 2.17.1 > >>> > >> > > > > . > > >