On 2021/8/5 8:05, Bjorn Helgaas wrote:
On Wed, Aug 04, 2021 at 09:47:07PM +0800, Dongdong Liu wrote:
PCIe spec 5.0 r1.0 section 2.2.6.2 says that if an Endpoint supports
sending Requests to other Endpoints (as opposed to host memory), the
Endpoint must not send 10-Bit Tag Requests to another given Endpoint
unless an implementation-specific mechanism determines that the
Endpoint supports 10-Bit Tag Completer capability.
Add sriov_vf_10bit_tag file to query the status of VF 10-Bit Tag
Requester Enable. Add sriov_vf_10bit_tag_ctl file to disable the VF
10-Bit Tag Requester. The typical use case is for p2pdma when the peer
device does not support 10-BIT Tag Completer.
Fix the usual spec quoting issue. Or maybe this is not actually
quoted but is missing blank lines between paragraphs.
Will fix.
s/10-BIT/10-Bit/
Will fix.
Signed-off-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-pci | 20 +++++++++++++
drivers/pci/iov.c | 50 +++++++++++++++++++++++++++++++++
2 files changed, 70 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 0e0c97d..8fdbfae 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -421,3 +421,23 @@ Description:
to disable 10-Bit Tag Requester when the driver does not bind
the deivce. The typical use case is for p2pdma when the peer
device does not support 10-BIT Tag Completer.
+
+What: /sys/bus/pci/devices/.../sriov_vf_10bit_tag
+Date: August 2021
+Contact: Dongdong Liu <liudongdong3@xxxxxxxxxx>
+Description:
+ This file is associated with a SR-IOV physical function (PF).
+ It is visible when the device has VF 10-Bit Tag Requester
+ Supported. It contains the status of VF 10-Bit Tag Requester
+ Enable. The file is only readable.
s/only readable/read-only/
Will fix.
+What: /sys/bus/pci/devices/.../sriov_vf_10bit_tag_ctl
Why does this file have "_ctl" on the end when the one in patch 7/9
does not?
+Date: August 2021
+Contact: Dongdong Liu <liudongdong3@xxxxxxxxxx>
+Description:
+ This file is associated with a SR-IOV virtual function (VF).
+ It is visible when the device has VF 10-Bit Tag Requester
+ Supported. It only allows to write 0 to disable VF 10-Bit
+ Tag Requester. The file is only writeable when the vf driver
+ does not bind to a dirver. The typical use case is for p2pdma
+ when the peer device does not support 10-BIT Tag Completer.
s/vf/VF/
s/dirver/driver/
s/10-BIT/10-Bit/
Will fix.
"when the vr driver does not bind to a driver"? Not quite right.
Must be a "device" in there somewhere.
Will fix.
So IIUC this file is associated with a VF, but the bit it writes is
actually in the *PF*? So writing 0 to any VF's file disables 10-bit
tags for *all* VFs? That's worth mentioning here.
Yes, will do.
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 0d0bed1..04c1298 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -220,10 +220,38 @@ static ssize_t sriov_vf_msix_count_store(struct device *dev,
static DEVICE_ATTR_WO(sriov_vf_msix_count);
#endif
+static ssize_t sriov_vf_10bit_tag_ctl_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pci_dev *vf_dev = to_pci_dev(dev);
+ struct pci_dev *pdev = pci_physfn(vf_dev);
+ struct pci_sriov *iov;
+ bool enable;
+
+ if (kstrtobool(buf, &enable) < 0)
+ return -EINVAL;
+
+ if (enable != false)
+ return -EINVAL;
Is this "if (enable)" again?
Will fix.
+ if (vf_dev->driver)
+ return -EBUSY;
+
+ iov = pdev->sriov;
+ iov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
+ pci_write_config_word(pdev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
+ pci_info(pdev, "disabled SRIOV 10-Bit Tag Requester\n");
s/SRIOV/SR-IOV/ to match spec and other usages.
Will fix.
Thanks,
Dongdong
+
+ return count;
+}
+static DEVICE_ATTR_WO(sriov_vf_10bit_tag_ctl);
+
static struct attribute *sriov_vf_dev_attrs[] = {
#ifdef CONFIG_PCI_MSI
&dev_attr_sriov_vf_msix_count.attr,
#endif
+ &dev_attr_sriov_vf_10bit_tag_ctl.attr,
NULL,
};
@@ -236,6 +264,11 @@ static umode_t sriov_vf_attrs_are_visible(struct kobject *kobj,
if (!pdev->is_virtfn)
return 0;
+ pdev = pci_physfn(pdev);
+ if ((a == &dev_attr_sriov_vf_10bit_tag_ctl.attr) &&
+ !(pdev->sriov->cap & PCI_SRIOV_CAP_VF_10BIT_TAG_REQ))
+ return 0;
+
return a->mode;
}
@@ -487,12 +520,23 @@ static ssize_t sriov_drivers_autoprobe_store(struct device *dev,
return count;
}
+static ssize_t sriov_vf_10bit_tag_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+
+ return sysfs_emit(buf, "%u\n",
+ !!(pdev->sriov->ctrl & PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN));
+}
+
static DEVICE_ATTR_RO(sriov_totalvfs);
static DEVICE_ATTR_RW(sriov_numvfs);
static DEVICE_ATTR_RO(sriov_offset);
static DEVICE_ATTR_RO(sriov_stride);
static DEVICE_ATTR_RO(sriov_vf_device);
static DEVICE_ATTR_RW(sriov_drivers_autoprobe);
+static DEVICE_ATTR_RO(sriov_vf_10bit_tag);
static struct attribute *sriov_pf_dev_attrs[] = {
&dev_attr_sriov_totalvfs.attr,
@@ -501,6 +545,7 @@ static struct attribute *sriov_pf_dev_attrs[] = {
&dev_attr_sriov_stride.attr,
&dev_attr_sriov_vf_device.attr,
&dev_attr_sriov_drivers_autoprobe.attr,
+ &dev_attr_sriov_vf_10bit_tag.attr,
#ifdef CONFIG_PCI_MSI
&dev_attr_sriov_vf_total_msix.attr,
#endif
@@ -511,10 +556,15 @@ static umode_t sriov_pf_attrs_are_visible(struct kobject *kobj,
struct attribute *a, int n)
{
struct device *dev = kobj_to_dev(kobj);
+ struct pci_dev *pdev = to_pci_dev(dev);
if (!dev_is_pf(dev))
return 0;
+ if ((a == &dev_attr_sriov_vf_10bit_tag.attr) &&
+ !(pdev->sriov->cap & PCI_SRIOV_CAP_VF_10BIT_TAG_REQ))
+ return 0;
+
return a->mode;
}
--
2.7.4
.
