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Subject[PATCH 30/34] x86/amd-iommu: Cleanup attach/detach_device code
Date
This patch cleans up the attach_device and detach_device
paths and fixes reference counting while at it.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/kernel/amd_iommu.c | 102 ++++++++++++++++++++++++------------------
1 files changed, 58 insertions(+), 44 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 530d608..e3363fd 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1329,7 +1329,6 @@ static bool dma_ops_domain(struct protection_domain *domain)

static void set_dte_entry(u16 devid, struct protection_domain *domain)
{
- struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
u64 pte_root = virt_to_phys(domain->pt_root);

BUG_ON(amd_iommu_pd_table[devid] != NULL);
@@ -1344,18 +1343,11 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain)

amd_iommu_pd_table[devid] = domain;

- /* Do reference counting */
- domain->dev_iommu[iommu->index] += 1;
- domain->dev_cnt += 1;
-
- /* Flush the changes DTE entry */
- iommu_queue_inv_dev_entry(iommu, devid);
}

static void clear_dte_entry(u16 devid)
{
struct protection_domain *domain = amd_iommu_pd_table[devid];
- struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];

BUG_ON(domain == NULL);

@@ -1368,11 +1360,51 @@ static void clear_dte_entry(u16 devid)
amd_iommu_dev_table[devid].data[2] = 0;

amd_iommu_apply_erratum_63(devid);
+}
+
+static void do_attach(struct device *dev, struct protection_domain *domain)
+{
+ struct iommu_dev_data *dev_data;
+ struct amd_iommu *iommu;
+ u16 devid;
+
+ devid = get_device_id(dev);
+ iommu = amd_iommu_rlookup_table[devid];
+ dev_data = get_dev_data(dev);
+
+ /* Update data structures */
+ dev_data->domain = domain;
+ list_add(&dev_data->list, &domain->dev_list);
+ set_dte_entry(devid, domain);
+
+ /* Do reference counting */
+ domain->dev_iommu[iommu->index] += 1;
+ domain->dev_cnt += 1;
+
+ /* Flush the DTE entry */
+ iommu_queue_inv_dev_entry(iommu, devid);
+}
+
+static void do_detach(struct device *dev)
+{
+ struct iommu_dev_data *dev_data;
+ struct amd_iommu *iommu;
+ u16 devid;
+
+ devid = get_device_id(dev);
+ iommu = amd_iommu_rlookup_table[devid];
+ dev_data = get_dev_data(dev);

/* decrease reference counters */
- domain->dev_iommu[iommu->index] -= 1;
- domain->dev_cnt -= 1;
+ dev_data->domain->dev_iommu[iommu->index] -= 1;
+ dev_data->domain->dev_cnt -= 1;
+
+ /* Update data structures */
+ dev_data->domain = NULL;
+ list_del(&dev_data->list);
+ clear_dte_entry(devid);

+ /* Flush the DTE entry */
iommu_queue_inv_dev_entry(iommu, devid);
}

@@ -1384,12 +1416,10 @@ static int __attach_device(struct device *dev,
struct protection_domain *domain)
{
struct iommu_dev_data *dev_data, *alias_data;
- u16 devid, alias;

- devid = get_device_id(dev);
- alias = amd_iommu_alias_table[devid];
dev_data = get_dev_data(dev);
alias_data = get_dev_data(dev_data->alias);
+
if (!alias_data)
return -EINVAL;

@@ -1406,21 +1436,16 @@ static int __attach_device(struct device *dev,
return -EBUSY;

/* Do real assignment */
- if (alias != devid) {
- if (alias_data->domain == NULL) {
- alias_data->domain = domain;
- list_add(&alias_data->list, &domain->dev_list);
- set_dte_entry(alias, domain);
- }
+ if (dev_data->alias != dev) {
+ alias_data = get_dev_data(dev_data->alias);
+ if (alias_data->domain == NULL)
+ do_attach(dev_data->alias, domain);

atomic_inc(&alias_data->bind);
}

- if (dev_data->domain == NULL) {
- dev_data->domain = domain;
- list_add(&dev_data->list, &domain->dev_list);
- set_dte_entry(devid, domain);
- }
+ if (dev_data->domain == NULL)
+ do_attach(dev, domain);

atomic_inc(&dev_data->bind);

@@ -1459,35 +1484,24 @@ static int attach_device(struct device *dev,
*/
static void __detach_device(struct device *dev)
{
- u16 devid = get_device_id(dev), alias;
- struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
struct iommu_dev_data *dev_data = get_dev_data(dev);
struct iommu_dev_data *alias_data;
unsigned long flags;

- BUG_ON(!iommu);
+ BUG_ON(!dev_data->domain);

- devid = get_device_id(dev);
- alias = get_device_id(dev_data->alias);
+ spin_lock_irqsave(&dev_data->domain->lock, flags);

- if (devid != alias) {
+ if (dev_data->alias != dev) {
alias_data = get_dev_data(dev_data->alias);
- if (atomic_dec_and_test(&alias_data->bind)) {
- spin_lock_irqsave(&alias_data->domain->lock, flags);
- clear_dte_entry(alias);
- list_del(&alias_data->list);
- spin_unlock_irqrestore(&alias_data->domain->lock, flags);
- alias_data->domain = NULL;
- }
+ if (atomic_dec_and_test(&alias_data->bind))
+ do_detach(dev_data->alias);
}

- if (atomic_dec_and_test(&dev_data->bind)) {
- spin_lock_irqsave(&dev_data->domain->lock, flags);
- clear_dte_entry(devid);
- list_del(&dev_data->list);
- spin_unlock_irqrestore(&dev_data->domain->lock, flags);
- dev_data->domain = NULL;
- }
+ if (atomic_dec_and_test(&dev_data->bind))
+ do_detach(dev);
+
+ spin_unlock_irqrestore(&dev_data->domain->lock, flags);

/*
* If we run in passthrough mode the device must be assigned to the
--
1.6.5.3



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