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iommu/amd: Use iommu_group_get_for_dev()
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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@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Alex Williamson authored and Joerg Roedel committed Jul 4, 2014
1 parent c193109 commit 65d5352
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Showing 2 changed files with 5 additions and 160 deletions.
164 changes: 5 additions & 159 deletions drivers/iommu/amd_iommu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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))

Expand Down Expand Up @@ -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);
}

Expand Down Expand Up @@ -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)
Expand Down
1 change: 0 additions & 1 deletion drivers/iommu/amd_iommu_types.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
Expand Down

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