[RFC KERNEL PATCH v4 3/3] PCI/sysfs: Add gsi sysfs for pci_dev

Jiqian Chen
2024-01-05T06:22:56Z

There is a need for some scenarios to use gsi sysfs.
For example, when xen passthrough a device to dumU, it will
use gsi to map pirq, but currently userspace can't get gsi
number.
So, add gsi sysfs for that and for other potential scenarios.

Co-developed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
---
drivers/acpi/pci_irq.c | 1 +
drivers/pci/pci-sysfs.c | 11 +++++++++++
include/linux/pci.h | 2 ++
3 files changed, 14 insertions(+)

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 630fe0a34bc6..739a58755df2 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -449,6 +449,7 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
kfree(entry);
return 0;
}
+ dev->gsi = gsi;

rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
if (rc < 0) {
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 2321fdfefd7d..c51df88d079e 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -71,6 +71,16 @@ static ssize_t irq_show(struct device *dev,
}
static DEVICE_ATTR_RO(irq);

+static ssize_t gsi_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->gsi);
+}
+static DEVICE_ATTR_RO(gsi);
+
static ssize_t broken_parity_status_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -596,6 +606,7 @@ static struct attribute *pci_dev_attrs[] = {
&dev_attr_revision.attr,
&dev_attr_class.attr,
&dev_attr_irq.attr,
+ &dev_attr_gsi.attr,
&dev_attr_local_cpus.attr,
&dev_attr_local_cpulist.attr,
&dev_attr_modalias.attr,
diff --git a/include/linux/pci.h b/include/linux/pci.h
index dea043bc1e38..0618d4a87a50 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -529,6 +529,8 @@ struct pci_dev {

/* These methods index pci_reset_fn_methods[] */
u8 reset_methods[PCI_NUM_RESET_METHODS]; /* In priority order */
+
+ unsigned int gsi;
};

static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
--
2.34.1