Re: [PATCH] PCI: Add pci reset quirk for Huawei Intelligent NIC virtual function
From: Chiqijun
Date: Thu Dec 03 2020 - 06:30:04 EST
On 2020/12/3 1:46, Alex Williamson wrote:
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
The firmware has always supported regular FLR. The regular FLR process
waits for 100ms after the FLR is triggered and the FLR is considered to
be completed, but the Huawei Intelligent NIC will exceed 100ms when the
VF FLR is parallel, so we now need to increase the host to confirm that
the firmware completes the FLR processing operation.
So in the probe stage, we return to support FLR, but there is no place
to return whether the firmware supports FLR completion ack capability.
We need to add checks during FLR, If the firmware does not support FLR
completion ack capability, then return -ENOTTY, the kernel will still
execute the regular FLR process.
+
+ 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
.
.