x86/amd-iommu: Let domain_for_device handle aliases

If there is no domain associated to a device yet and the
device has an alias device which already has a domain, the
original device needs to have the same domain as the alias
device.
This patch changes domain_for_device to handle this
situation and directly assigns the alias device domain to
the device in this situation.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 135 insertions, 92 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 2cd5800e6888..75470ffee358 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -71,6 +71,19 @@ static u64 *fetch_pte(struct protection_domain *domain,
                       unsigned long address, int map_size);
 static void update_domain(struct protection_domain *domain);
 
+/****************************************************************************
+ *
+ * Helper functions
+ *
+ ****************************************************************************/
+
+static inline u16 get_device_id(struct device *dev)
+{
+        struct pci_dev *pdev = to_pci_dev(dev);
+
+        return calc_devid(pdev->bus->number, pdev->devfn);
+}
+
 #ifdef CONFIG_AMD_IOMMU_STATS
 
 /*
@@ -1174,26 +1187,13 @@ static bool dma_ops_domain(struct protection_domain *domain)
         return domain->flags & PD_DMA_OPS_MASK;
 }
 
-/*
- * Find out the protection domain structure for a given PCI device. This
- * will give us the pointer to the page table root for example.
- */
-static struct protection_domain *domain_for_device(u16 devid)
-{
-        struct protection_domain *dom;
-        unsigned long flags;
-
-        read_lock_irqsave(&amd_iommu_devtable_lock, flags);
-        dom = amd_iommu_pd_table[devid];
-        read_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
-
-        return dom;
-}
-
 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);
+
         pte_root |= (domain->mode & DEV_ENTRY_MODE_MASK)
                     << DEV_ENTRY_MODE_SHIFT;
         pte_root |= IOMMU_PTE_IR | IOMMU_PTE_IW | IOMMU_PTE_P | IOMMU_PTE_TV;
@@ -1203,42 +1203,87 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain)
         amd_iommu_dev_table[devid].data[0] = lower_32_bits(pte_root);
 
         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);
+
+        /* remove domain from the lookup table */
+        amd_iommu_pd_table[devid] = NULL;
+
+        /* remove entry from the device table seen by the hardware */
+        amd_iommu_dev_table[devid].data[0] = IOMMU_PTE_P | IOMMU_PTE_TV;
+        amd_iommu_dev_table[devid].data[1] = 0;
+        amd_iommu_dev_table[devid].data[2] = 0;
+
+        amd_iommu_apply_erratum_63(devid);
+
+        /* decrease reference counters */
+        domain->dev_iommu[iommu->index] -= 1;
+        domain->dev_cnt                 -= 1;
+
+        iommu_queue_inv_dev_entry(iommu, devid);
 }
 
 /*
  * If a device is not yet associated with a domain, this function does
  * assigns it visible for the hardware
  */
-static void __attach_device(struct amd_iommu *iommu,
-                            struct protection_domain *domain,
-                            u16 devid)
+static int __attach_device(struct device *dev,
+                           struct protection_domain *domain)
 {
+        u16 devid = get_device_id(dev);
+        u16 alias = amd_iommu_alias_table[devid];
+
         /* lock domain */
         spin_lock(&domain->lock);
 
-        /* update DTE entry */
-        set_dte_entry(devid, domain);
+        /* Some sanity checks */
+        if (amd_iommu_pd_table[alias] != NULL &&
+            amd_iommu_pd_table[alias] != domain)
+                return -EBUSY;
 
-        /* Do reference counting */
-        domain->dev_iommu[iommu->index] += 1;
-        domain->dev_cnt                 += 1;
+        if (amd_iommu_pd_table[devid] != NULL &&
+            amd_iommu_pd_table[devid] != domain)
+                return -EBUSY;
+
+        /* Do real assignment */
+        if (alias != devid &&
+            amd_iommu_pd_table[alias] == NULL)
+                set_dte_entry(alias, domain);
+
+        if (amd_iommu_pd_table[devid] == NULL)
+                set_dte_entry(devid, domain);
 
         /* ready */
         spin_unlock(&domain->lock);
+
+        return 0;
 }
 
 /*
  * If a device is not yet associated with a domain, this function does
  * assigns it visible for the hardware
  */
-static void attach_device(struct amd_iommu *iommu,
-                          struct protection_domain *domain,
-                          u16 devid)
+static int attach_device(struct device *dev,
+                         struct protection_domain *domain)
 {
         unsigned long flags;
+        int ret;
 
         write_lock_irqsave(&amd_iommu_devtable_lock, flags);
-        __attach_device(iommu, domain, devid);
+        ret = __attach_device(dev, domain);
         write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 
         /*
@@ -1246,62 +1291,70 @@ static void attach_device(struct amd_iommu *iommu,
          * left the caches in the IOMMU dirty. So we have to flush
          * here to evict all dirty stuff.
          */
-        iommu_queue_inv_dev_entry(iommu, devid);
         iommu_flush_tlb_pde(domain);
+
+        return ret;
 }
 
 /*
  * Removes a device from a protection domain (unlocked)
  */
-static void __detach_device(struct protection_domain *domain, u16 devid)
+static void __detach_device(struct device *dev)
 {
+        u16 devid = get_device_id(dev);
         struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
 
         BUG_ON(!iommu);
 
-        /* lock domain */
-        spin_lock(&domain->lock);
-
-        /* remove domain from the lookup table */
-        amd_iommu_pd_table[devid] = NULL;
-
-        /* remove entry from the device table seen by the hardware */
-        amd_iommu_dev_table[devid].data[0] = IOMMU_PTE_P | IOMMU_PTE_TV;
-        amd_iommu_dev_table[devid].data[1] = 0;
-        amd_iommu_dev_table[devid].data[2] = 0;
-
-        amd_iommu_apply_erratum_63(devid);
-
-        /* decrease reference counters */
-        domain->dev_iommu[iommu->index] -= 1;
-        domain->dev_cnt                 -= 1;
-
-        /* ready */
-        spin_unlock(&domain->lock);
+        clear_dte_entry(devid);
 
         /*
          * If we run in passthrough mode the device must be assigned to the
          * passthrough domain if it is detached from any other domain
          */
-        if (iommu_pass_through) {
-                struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
-                __attach_device(iommu, pt_domain, devid);
-        }
+        if (iommu_pass_through)
+                __attach_device(dev, pt_domain);
 }
 
 /*
  * Removes a device from a protection domain (with devtable_lock held)
  */
-static void detach_device(struct protection_domain *domain, u16 devid)
+static void detach_device(struct device *dev)
 {
         unsigned long flags;
 
         /* lock device table */
         write_lock_irqsave(&amd_iommu_devtable_lock, flags);
-        __detach_device(domain, devid);
+        __detach_device(dev);
         write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 }
 
+/*
+ * Find out the protection domain structure for a given PCI device. This
+ * will give us the pointer to the page table root for example.
+ */
+static struct protection_domain *domain_for_device(struct device *dev)
+{
+        struct protection_domain *dom;
+        unsigned long flags;
+        u16 devid, alias;
+
+        devid = get_device_id(dev);
+        alias = amd_iommu_alias_table[devid];
+
+        read_lock_irqsave(&amd_iommu_devtable_lock, flags);
+        dom = amd_iommu_pd_table[devid];
+        if (dom == NULL &&
+            amd_iommu_pd_table[alias] != NULL) {
+                __attach_device(dev, amd_iommu_pd_table[alias]);
+                dom = amd_iommu_pd_table[devid];
+        }
+
+        read_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+
+        return dom;
+}
+
 static int device_change_notifier(struct notifier_block *nb,
                                   unsigned long action, void *data)
 {
@@ -1322,7 +1375,7 @@ static int device_change_notifier(struct notifier_block *nb,
         if (iommu == NULL)
                 goto out;
 
-        domain = domain_for_device(devid);
+        domain = domain_for_device(dev);
 
         if (domain && !dma_ops_domain(domain))
                 WARN_ONCE(1, "AMD IOMMU WARNING: device %s already bound "
@@ -1334,7 +1387,7 @@ static int device_change_notifier(struct notifier_block *nb,
                         goto out;
                 if (iommu_pass_through)
                         break;
-                detach_device(domain, devid);
+                detach_device(dev);
                 break;
         case BUS_NOTIFY_ADD_DEVICE:
                 /* allocate a protection domain if a device is added */
@@ -1441,30 +1494,25 @@ static bool get_device_resources(struct device *dev,
 {
         struct dma_ops_domain *dma_dom;
         struct amd_iommu *iommu;
-        struct pci_dev *pcidev;
-        u16 _bdf;
 
         if (!check_device(dev))
                 return false;
 
-        pcidev  = to_pci_dev(dev);
-        _bdf    = calc_devid(pcidev->bus->number, pcidev->devfn);
-        *bdf    = amd_iommu_alias_table[_bdf];
+        *bdf    = get_device_id(dev);
+        *domain = domain_for_device(dev);
         iommu   = amd_iommu_rlookup_table[*bdf];
-        *domain = domain_for_device(*bdf);
 
-        if (*domain == NULL) {
-                dma_dom = find_protection_domain(*bdf);
-                if (!dma_dom)
-                        dma_dom = iommu->default_dom;
-                *domain = &dma_dom->domain;
-                attach_device(iommu, *domain, *bdf);
-                DUMP_printk("Using protection domain %d for device %s\n",
-                            (*domain)->id, dev_name(dev));
-        }
+        if (*domain != NULL)
+                return true;
 
-        if (domain_for_device(_bdf) == NULL)
-                attach_device(iommu, *domain, _bdf);
+        /* Device not bount yet - bind it */
+        dma_dom = find_protection_domain(*bdf);
+        if (!dma_dom)
+                dma_dom = iommu->default_dom;
+        *domain = &dma_dom->domain;
+        attach_device(dev, *domain);
+        DUMP_printk("Using protection domain %d for device %s\n",
+                    (*domain)->id, dev_name(dev));
 
         return true;
 }
@@ -2068,7 +2116,7 @@ static void prealloc_protection_domains(void)
                 if (devid > amd_iommu_last_bdf)
                         continue;
                 devid = amd_iommu_alias_table[devid];
-                if (domain_for_device(devid))
+                if (domain_for_device(&dev->dev))
                         continue;
                 iommu = amd_iommu_rlookup_table[devid];
                 if (!iommu)
@@ -2079,9 +2127,7 @@ static void prealloc_protection_domains(void)
                 init_unity_mappings_for_device(dma_dom, devid);
                 dma_dom->target_dev = devid;
 
-                attach_device(iommu, &dma_dom->domain, devid);
-                if (__devid != devid)
-                        attach_device(iommu, &dma_dom->domain, __devid);
+                attach_device(&dev->dev, &dma_dom->domain);
 
                 list_add_tail(&dma_dom->list, &iommu_pd_list);
         }
@@ -2174,7 +2220,7 @@ static void cleanup_domain(struct protection_domain *domain)
 
         for (devid = 0; devid <= amd_iommu_last_bdf; ++devid)
                 if (amd_iommu_pd_table[devid] == domain)
-                        __detach_device(domain, devid);
+                        clear_dte_entry(devid);
 
         write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 }
@@ -2262,7 +2308,6 @@ static void amd_iommu_domain_destroy(struct iommu_domain *dom)
 static void amd_iommu_detach_device(struct iommu_domain *dom,
                                     struct device *dev)
 {
-        struct protection_domain *domain = dom->priv;
         struct amd_iommu *iommu;
         struct pci_dev *pdev;
         u16 devid;
@@ -2275,7 +2320,7 @@ static void amd_iommu_detach_device(struct iommu_domain *dom,
         devid = calc_devid(pdev->bus->number, pdev->devfn);
 
         if (devid > 0)
-                detach_device(domain, devid);
+                detach_device(dev);
 
         iommu = amd_iommu_rlookup_table[devid];
         if (!iommu)
@@ -2292,6 +2337,7 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
         struct protection_domain *old_domain;
         struct amd_iommu *iommu;
         struct pci_dev *pdev;
+        int ret;
         u16 devid;
 
         if (dev->bus != &pci_bus_type)
@@ -2309,15 +2355,15 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
         if (!iommu)
                 return -EINVAL;
 
-        old_domain = domain_for_device(devid);
+        old_domain = amd_iommu_pd_table[devid];
         if (old_domain)
-                detach_device(old_domain, devid);
+                detach_device(dev);
 
-        attach_device(iommu, domain, devid);
+        ret = attach_device(dev, domain);
 
         iommu_completion_wait(iommu);
 
-        return 0;
+        return ret;
 }
 
 static int amd_iommu_map_range(struct iommu_domain *dom,
@@ -2414,8 +2460,9 @@ static struct iommu_ops amd_iommu_ops = {
 
 int __init amd_iommu_init_passthrough(void)
 {
+        struct amd_iommu *iommu;
         struct pci_dev *dev = NULL;
-        u16 devid, devid2;
+        u16 devid;
 
         /* allocate passthroug domain */
         pt_domain = protection_domain_alloc();
@@ -2425,20 +2472,16 @@ int __init amd_iommu_init_passthrough(void)
         pt_domain->mode |= PAGE_MODE_NONE;
 
         while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
-                struct amd_iommu *iommu;
 
                 devid = calc_devid(dev->bus->number, dev->devfn);
                 if (devid > amd_iommu_last_bdf)
                         continue;
 
-                devid2 = amd_iommu_alias_table[devid];
-
-                iommu = amd_iommu_rlookup_table[devid2];
+                iommu = amd_iommu_rlookup_table[devid];
                 if (!iommu)
                         continue;
 
-                __attach_device(iommu, pt_domain, devid);
-                __attach_device(iommu, pt_domain, devid2);
+                attach_device(&dev->dev, pt_domain);
         }
 
         pr_info("AMD-Vi: Initialized for Passthrough Mode\n");