[PATCH 3/7] iommu/amd: Use iommu_group_get_for_dev()

From: Alex Williamson
Date: Thu Jul 03 2014 - 11:51:43 EST


The common iommu_group_get_for_dev() allows us to greatly simplify
our group lookup for a new device. Also, since we insert IVRS
aliases into the PCI DMA alias quirks, we should alway come up with
the same results as the existing code.

Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
---

drivers/iommu/amd_iommu.c | 164 +--------------------------------------
drivers/iommu/amd_iommu_types.h | 1
2 files changed, 5 insertions(+), 160 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 25d7571..2e03c17 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -46,7 +46,6 @@
#include "amd_iommu_proto.h"
#include "amd_iommu_types.h"
#include "irq_remapping.h"
-#include "pci.h"

#define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))

@@ -133,9 +132,6 @@ static void free_dev_data(struct iommu_dev_data *dev_data)
list_del(&dev_data->dev_data_list);
spin_unlock_irqrestore(&dev_data_list_lock, flags);

- if (dev_data->group)
- iommu_group_put(dev_data->group);
-
kfree(dev_data);
}

@@ -264,167 +260,17 @@ static bool check_device(struct device *dev)
return true;
}

-static struct pci_bus *find_hosted_bus(struct pci_bus *bus)
-{
- while (!bus->self) {
- if (!pci_is_root_bus(bus))
- bus = bus->parent;
- else
- return ERR_PTR(-ENODEV);
- }
-
- return bus;
-}
-
-#define REQ_ACS_FLAGS (PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
-
-static struct pci_dev *get_isolation_root(struct pci_dev *pdev)
-{
- struct pci_dev *dma_pdev = pdev;
-
- /* Account for quirked devices */
- swap_pci_ref(&dma_pdev, pci_get_dma_source(dma_pdev));
-
- /*
- * If it's a multifunction device that does not support our
- * required ACS flags, add to the same group as lowest numbered
- * function that also does not suport the required ACS flags.
- */
- if (dma_pdev->multifunction &&
- !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) {
- u8 i, slot = PCI_SLOT(dma_pdev->devfn);
-
- for (i = 0; i < 8; i++) {
- struct pci_dev *tmp;
-
- tmp = pci_get_slot(dma_pdev->bus, PCI_DEVFN(slot, i));
- if (!tmp)
- continue;
-
- if (!pci_acs_enabled(tmp, REQ_ACS_FLAGS)) {
- swap_pci_ref(&dma_pdev, tmp);
- break;
- }
- pci_dev_put(tmp);
- }
- }
-
- /*
- * Devices on the root bus go through the iommu. If that's not us,
- * find the next upstream device and test ACS up to the root bus.
- * Finding the next device may require skipping virtual buses.
- */
- while (!pci_is_root_bus(dma_pdev->bus)) {
- struct pci_bus *bus = find_hosted_bus(dma_pdev->bus);
- if (IS_ERR(bus))
- break;
-
- if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))
- break;
-
- swap_pci_ref(&dma_pdev, pci_dev_get(bus->self));
- }
-
- return dma_pdev;
-}
-
-static int use_pdev_iommu_group(struct pci_dev *pdev, struct device *dev)
-{
- struct iommu_group *group = iommu_group_get(&pdev->dev);
- int ret;
-
- if (!group) {
- group = iommu_group_alloc();
- if (IS_ERR(group))
- return PTR_ERR(group);
-
- WARN_ON(&pdev->dev != dev);
- }
-
- ret = iommu_group_add_device(group, dev);
- iommu_group_put(group);
- return ret;
-}
-
-static int use_dev_data_iommu_group(struct iommu_dev_data *dev_data,
- struct device *dev)
-{
- if (!dev_data->group) {
- struct iommu_group *group = iommu_group_alloc();
- if (IS_ERR(group))
- return PTR_ERR(group);
-
- dev_data->group = group;
- }
-
- return iommu_group_add_device(dev_data->group, dev);
-}
-
static int init_iommu_group(struct device *dev)
{
- struct iommu_dev_data *dev_data;
struct iommu_group *group;
- struct pci_dev *dma_pdev;
- int ret;

- group = iommu_group_get(dev);
- if (group) {
- iommu_group_put(group);
- return 0;
- }
+ group = iommu_group_get_for_dev(dev);

- dev_data = find_dev_data(get_device_id(dev));
- if (!dev_data)
- return -ENOMEM;
-
- if (dev_data->alias_data) {
- u16 alias;
- struct pci_bus *bus;
-
- if (dev_data->alias_data->group)
- goto use_group;
+ if (IS_ERR(group))
+ return PTR_ERR(group);

- /*
- * If the alias device exists, it's effectively just a first
- * level quirk for finding the DMA source.
- */
- alias = amd_iommu_alias_table[dev_data->devid];
- dma_pdev = pci_get_bus_and_slot(alias >> 8, alias & 0xff);
- if (dma_pdev) {
- dma_pdev = get_isolation_root(dma_pdev);
- goto use_pdev;
- }
-
- /*
- * If the alias is virtual, try to find a parent device
- * and test whether the IOMMU group is actualy rooted above
- * the alias. Be careful to also test the parent device if
- * we think the alias is the root of the group.
- */
- bus = pci_find_bus(0, alias >> 8);
- if (!bus)
- goto use_group;
-
- bus = find_hosted_bus(bus);
- if (IS_ERR(bus) || !bus->self)
- goto use_group;
-
- dma_pdev = get_isolation_root(pci_dev_get(bus->self));
- if (dma_pdev != bus->self || (dma_pdev->multifunction &&
- !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)))
- goto use_pdev;
-
- pci_dev_put(dma_pdev);
- goto use_group;
- }
-
- dma_pdev = get_isolation_root(pci_dev_get(to_pci_dev(dev)));
-use_pdev:
- ret = use_pdev_iommu_group(dma_pdev, dev);
- pci_dev_put(dma_pdev);
- return ret;
-use_group:
- return use_dev_data_iommu_group(dev_data->alias_data, dev);
+ iommu_group_put(group);
+ return 0;
}

static int __last_alias(struct pci_dev *pdev, u16 alias, void *data)
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index f1a5abf..7277a20 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -432,7 +432,6 @@ struct iommu_dev_data {
struct iommu_dev_data *alias_data;/* The alias dev_data */
struct protection_domain *domain; /* Domain the device is bound to */
atomic_t bind; /* Domain attach reference count */
- struct iommu_group *group; /* IOMMU group for virtual aliases */
u16 devid; /* PCI Device ID */
bool iommu_v2; /* Device can make use of IOMMUv2 */
bool passthrough; /* Default for device is pt_domain */

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