UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

Merge branch 'pci/peer-to-peer' 

- Add a whitelist of Root Complexes known to support peer-to-peer DMA
    between Root Ports (Christian König)

* pci/peer-to-peer:
  PCI/P2PDMA: Allow P2P DMA between any devices under AMD ZEN Root Complex
This commit is contained in:
Bjorn Helgaas 2019-05-13 18:34:33 -05:00
parent 09fdd75c18 0f97da8310
commit 292c939654
1 changed files with 35 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
drivers/pci/p2pdma.c
View File

@ -274,6 +274,30 @@ static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev)
seq_buf_printf(buf, "%s;", pci_name(pdev));
}
/*
* If we can't find a common upstream bridge take a look at the root
* complex and compare it to a whitelist of known good hardware.
*/
static bool root_complex_whitelist(struct pci_dev *dev)
{
struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0));
unsigned short vendor, device;
if (!root)
return false;
vendor = root->vendor;
device = root->device;
pci_dev_put(root);
/* AMD ZEN host bridges can do peer to peer */
if (vendor == PCI_VENDOR_ID_AMD && device == 0x1450)
return true;
return false;
}
/*
* Find the distance through the nearest common upstream bridge between
* two PCI devices.
@ -317,13 +341,13 @@ static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev)
* In this case, a list of all infringing bridge addresses will be
* populated in acs_list (assuming it's non-null) for printk purposes.
*/
static int upstream_bridge_distance(struct pci_dev *a,
struct pci_dev *b,
static int upstream_bridge_distance(struct pci_dev *provider,
struct pci_dev *client,
struct seq_buf *acs_list)
{
struct pci_dev *a = provider, *b = client, *bb;
int dist_a = 0;
int dist_b = 0;
struct pci_dev *bb = NULL;
int acs_cnt = 0;
/*
@ -354,6 +378,14 @@ static int upstream_bridge_distance(struct pci_dev *a,
dist_a++;
}
/*
* Allow the connection if both devices are on a whitelisted root
* complex, but add an arbitary large value to the distance.
*/
if (root_complex_whitelist(provider) &&
root_complex_whitelist(client))
return 0x1000 + dist_a + dist_b;
return -1;
check_b_path_acs: