iommu/vt-d: Allocate dynamic domain id for virtual domains only

Check the same domain id is allocated for si_domain on each IOMMU,
otherwise the IOTLB flush for si_domain will fail.

Now the rules to allocate and manage domain id are:
1) For normal and static identity domains, domain id is allocated
   when creating domain structure. And this id will be written into
   context entry.
2) For virtual machine domain, a virtual id is allocated when creating
   domain. And when binding virtual machine domain to an iommu, a real
   domain id is allocated on demand and this domain id will be written
   into context entry. So domain->id for virtual machine domain may be
   different from the domain id written into context entry(used by
   hardware).

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 26 insertions, 21 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index eae9b0d8bc60..968e3d32e305 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1549,15 +1549,27 @@ static int iommu_attach_domain(struct dmar_domain *domain,
 
         spin_lock_irqsave(&iommu->lock, flags);
         num = __iommu_attach_domain(domain, iommu);
+        spin_unlock_irqrestore(&iommu->lock, flags);
         if (num < 0)
                 pr_err("IOMMU: no free domain ids\n");
-        else
-                domain->id = num;
-        spin_unlock_irqrestore(&iommu->lock, flags);
 
         return num;
 }
 
+static int iommu_attach_vm_domain(struct dmar_domain *domain,
+                                  struct intel_iommu *iommu)
+{
+        int num;
+        unsigned long ndomains;
+
+        ndomains = cap_ndoms(iommu->cap);
+        for_each_set_bit(num, iommu->domain_ids, ndomains)
+                if (iommu->domains[num] == domain)
+                        return num;
+
+        return __iommu_attach_domain(domain, iommu);
+}
+
 static void iommu_detach_domain(struct dmar_domain *domain,
                                 struct intel_iommu *iommu)
 {
@@ -1764,8 +1776,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
         struct context_entry *context;
         unsigned long flags;
         struct dma_pte *pgd;
-        unsigned long num;
-        unsigned long ndomains;
         int id;
         int agaw;
         struct device_domain_info *info = NULL;
@@ -1790,20 +1800,8 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
         pgd = domain->pgd;
 
         if (domain_type_is_vm_or_si(domain)) {
-                int found = 0;
-
-                /* find an available domain id for this device in iommu */
-                ndomains = cap_ndoms(iommu->cap);
-                for_each_set_bit(num, iommu->domain_ids, ndomains) {
-                        if (iommu->domains[num] == domain) {
-                                id = num;
-                                found = 1;
-                                break;
-                        }
-                }
-
-                if (found == 0) {
-                        id = __iommu_attach_domain(domain, iommu);
+                if (domain_type_is_vm(domain)) {
+                        id = iommu_attach_vm_domain(domain, iommu);
                         if (id < 0) {
                                 spin_unlock_irqrestore(&iommu->lock, flags);
                                 pr_err("IOMMU: no free domain ids\n");
@@ -2257,8 +2255,8 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
         domain = alloc_domain(0);
         if (!domain)
                 return NULL;
-
-        if (iommu_attach_domain(domain, iommu) < 0) {
+        domain->id = iommu_attach_domain(domain, iommu);
+        if (domain->id < 0) {
                 free_domain_mem(domain);
                 return NULL;
         }
@@ -2428,6 +2426,7 @@ static int __init si_domain_init(int hw)
         struct dmar_drhd_unit *drhd;
         struct intel_iommu *iommu;
         int nid, ret = 0;
+        bool first = true;
 
         si_domain = alloc_domain(DOMAIN_FLAG_STATIC_IDENTITY);
         if (!si_domain)
@@ -2438,6 +2437,12 @@ static int __init si_domain_init(int hw)
                 if (ret < 0) {
                         domain_exit(si_domain);
                         return -EFAULT;
+                } else if (first) {
+                        si_domain->id = ret;
+                        first = false;
+                } else if (si_domain->id != ret) {
+                        domain_exit(si_domain);
+                        return -EFAULT;
                 }
                 domain_attach_iommu(si_domain, iommu);
         }