Intel IOMMU: PCI generic helper function

When devices are under a p2p bridge, upstream transactions get replaced by the
device id of the bridge as it owns the PCIE transaction.  Hence its necessary
to setup translations on behalf of the bridge as well.  Due to this limitation
all devices under a p2p share the same domain in a DMAR.

We just cache the type of device, if its a native PCIe device
or not for later use.

[akpm@linux-foundation.org: BUG_ON -> WARN_ON+recover]
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6fda33de84e85527f49b048db6889cd90815c75a..fc87e14b50de9a15b491ed800320fd9e01f6e7e5 100644 (file)
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -90,3 +90,4 @@ pci_match_one_device(const struct pci_device_id *id, const struct pci_dev *dev)
        return NULL;
 }
 
+struct pci_dev *pci_find_upstream_pcie_bridge(struct pci_dev *pdev);

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5db6b6690b596bb4ff5079673731e67c2773780d..463a5a9d583d03747323285a18df00d5e46d717c 100644 (file)
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -837,6 +837,19 @@ static void pci_release_dev(struct device *dev)
        kfree(pci_dev);
 }
 
+static void set_pcie_port_type(struct pci_dev *pdev)
+{
+       int pos;
+       u16 reg16;
+
+       pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
+       if (!pos)
+               return;
+       pdev->is_pcie = 1;
+       pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
+       pdev->pcie_type = (reg16 & PCI_EXP_FLAGS_TYPE) >> 4;
+}
+
 /**
  * pci_cfg_space_size - get the configuration space size of the PCI device.
  * @dev: PCI device
@@ -951,6 +964,7 @@ pci_scan_device(struct pci_bus *bus, int devfn)
        dev->device = (l >> 16) & 0xffff;
        dev->cfg_size = pci_cfg_space_size(dev);
        dev->error_state = pci_channel_io_normal;
+       set_pcie_port_type(dev);
 
        /* Assume 32-bit PCI; let 64-bit PCI cards (which are far rarer)
           set this higher, assuming the system even supports it.  */

diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index c6e79d01ce3d1a8e4f747a762f8e052712320102..b001b5922e3349088ac2e47b9ee3acb1d934a46e 100644 (file)
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -14,6 +14,40 @@
 #include "pci.h"
 
 DECLARE_RWSEM(pci_bus_sem);
+/*
+ * find the upstream PCIE-to-PCI bridge of a PCI device
+ * if the device is PCIE, return NULL
+ * if the device isn't connected to a PCIE bridge (that is its parent is a
+ * legacy PCI bridge and the bridge is directly connected to bus 0), return its
+ * parent
+ */
+struct pci_dev *
+pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
+{
+       struct pci_dev *tmp = NULL;
+
+       if (pdev->is_pcie)
+               return NULL;
+       while (1) {
+               if (!pdev->bus->self)
+                       break;
+               pdev = pdev->bus->self;
+               /* a p2p bridge */
+               if (!pdev->is_pcie) {
+                       tmp = pdev;
+                       continue;
+               }
+               /* PCI device should connect to a PCIE bridge */
+               if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
+                       /* Busted hardware? */
+                       WARN_ON_ONCE(1);
+                       return NULL;
+               }
+               return pdev;
+       }
+
+       return tmp;
+}
 
 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
 {

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 768b93359f9034268dc8db53923d63bec3d86df4..5d2281f661f77e70a13090d7508f8adcdbba9584 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -141,6 +141,7 @@ struct pci_dev {
        unsigned int    class;          /* 3 bytes: (base,sub,prog-if) */
        u8              revision;       /* PCI revision, low byte of class word */
        u8              hdr_type;       /* PCI header type (`multi' flag masked out) */
+       u8              pcie_type;      /* PCI-E device/port type */
        u8              rom_base_reg;   /* which config register controls the ROM */
        u8              pin;            /* which interrupt pin this device uses */
 
@@ -183,6 +184,7 @@ struct pci_dev {
        unsigned int    msi_enabled:1;
        unsigned int    msix_enabled:1;
        unsigned int    is_managed:1;
+       unsigned int    is_pcie:1;
        atomic_t        enable_cnt;     /* pci_enable_device has been called */
 
        u32             saved_config_space[16]; /* config space saved at suspend time */