[PATCH 1/3] xen:get p2pdma_distance

[Julia Zhang <julia.zhang@xxxxxxx>]

To get the p2pdma_distance, this create a new privcmd ioctl to calculate
p2pdma_distance for two pci devices on the host with pci notations sent
from guest virtgpu driver.

Signed-off-by: Julia Zhang <julia.zhang@xxxxxxx>
---
 drivers/xen/privcmd.c      | 42 ++++++++++++++++++++++++++++++++++++++
 include/uapi/xen/privcmd.h | 12 +++++++++++
 2 files changed, 54 insertions(+)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 72c161e94731..95f67815a2ef 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -31,6 +31,9 @@
 #include <linux/miscdevice.h>
 #include <linux/moduleparam.h>
 #include <linux/virtio_mmio.h>
+#include <linux/pci.h>
+#include <linux/pci-p2pdma.h>
+#include <linux/dma-map-ops.h>
 
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
@@ -977,6 +980,42 @@ static long privcmd_ioctl_map_hva_to_gpfns(struct file *file, void __user *udata
 	return ret;
 }
 
+static int privcmd_ioctl_p2pdma_distance(struct file *file, void __user *udata)
+{
+	struct privcmd_p2pdma_distance kdata;
+	struct pci_dev *provider = NULL;
+	struct pci_dev *client = NULL;
+	struct pci_dev *dev = NULL;
+	enum pci_p2pdma_map_type map;
+
+	if (copy_from_user(&kdata, udata, sizeof(kdata)))
+		return -EFAULT;
+
+	for_each_pci_dev(dev) {
+		if (dev->bus->number == kdata.provider_bus &&
+		    dev->devfn == PCI_DEVFN(kdata.provider_slot, kdata.provider_func)) {
+			provider = dev;
+		} else if (dev->bus->number == kdata.client_bus &&
+			   dev->devfn == PCI_DEVFN(kdata.client_slot, kdata.client_func)) {
+			client = dev;
+		} else {
+			continue;
+		}
+	}
+
+	if (!provider || !client) {
+		pr_err("%s fail to get provider or client.\n", __func__);
+		return -EINVAL;
+	}
+
+	kdata.distance = pci_p2pdma_distance(provider, &client->dev, false);
+
+	if (copy_to_user(udata, &kdata, sizeof(kdata)))
+		return -EFAULT;
+
+	return 0;
+}
+
 #ifdef CONFIG_XEN_PRIVCMD_EVENTFD
 /* Irqfd support */
 static struct workqueue_struct *irqfd_cleanup_wq;
@@ -1684,6 +1723,9 @@ static long privcmd_ioctl(struct file *file,
 		ret = privcmd_ioctl_map_hva_to_gpfns(file, udata);
 		break;
 
+	case IOCTL_PRIVCMD_P2PDMA_DISTANCE:
+		ret = privcmd_ioctl_p2pdma_distance(file, udata);
+		break;
 
 	default:
 		break;
diff --git a/include/uapi/xen/privcmd.h b/include/uapi/xen/privcmd.h
index d131002dd48f..a7ec3704519f 100644
--- a/include/uapi/xen/privcmd.h
+++ b/include/uapi/xen/privcmd.h
@@ -141,6 +141,16 @@ struct privcmd_map_hva_to_gpfns {
 	int add_mapping;
 };
 
+struct privcmd_p2pdma_distance {
+	__u32 provider_bus;
+	__u32 provider_slot;
+	__u32 provider_func;
+	__u32 client_bus;
+	__u32 client_slot;
+	__u32 client_func;
+	__u32 distance;
+};
+
 /*
  * @cmd: IOCTL_PRIVCMD_HYPERCALL
  * @arg: &privcmd_hypercall_t
@@ -174,6 +184,8 @@ struct privcmd_map_hva_to_gpfns {
 	_IOW('P', 9, struct privcmd_ioeventfd)
 #define IOCTL_PRIVCMD_PCIDEV_GET_GSI				\
 	_IOC(_IOC_NONE, 'P', 10, sizeof(struct privcmd_pcidev_get_gsi))
+#define IOCTL_PRIVCMD_P2PDMA_DISTANCE                          \
+	_IOC(_IOC_NONE, 'P', 11, sizeof(struct privcmd_p2pdma_distance))
 #define IOCTL_PRIVCMD_MAP_HVA_TO_GPFNS                          \
 	_IOC(_IOC_NONE, 'P', 13, sizeof(struct privcmd_map_hva_to_gpfns))
 
-- 
2.34.1