iommu/vt-d: Split up iommu->domains array

This array is indexed by the domain-id and contains the
pointers to the domains attached to this iommu. Modern
systems support 65536 domain ids, so that this array has a
size of 512kb, per iommu.

This is a huge waste of space, as the array is usually
sparsely populated. This patch makes the array
two-dimensional and allocates the memory for the domain
pointers on-demand.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1c2d612..90ab4b0 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -571,13 +571,32 @@ static struct kmem_cache *iommu_devinfo_cache;
 
 static struct dmar_domain* get_iommu_domain(struct intel_iommu *iommu, u16 did)
 {
-       return iommu->domains[did];
+       struct dmar_domain **domains;
+       int idx = did >> 8;
+
+       domains = iommu->domains[idx];
+       if (!domains)
+               return NULL;
+
+       return domains[did & 0xff];
 }
 
 static void set_iommu_domain(struct intel_iommu *iommu, u16 did,
                             struct dmar_domain *domain)
 {
-       iommu->domains[did] = domain;
+       struct dmar_domain **domains;
+       int idx = did >> 8;
+
+       if (!iommu->domains[idx]) {
+               size_t size = 256 * sizeof(struct dmar_domain *);
+               iommu->domains[idx] = kzalloc(size, GFP_ATOMIC);
+       }
+
+       domains = iommu->domains[idx];
+       if (WARN_ON(!domains))
+               return;
+       else
+               domains[did & 0xff] = domain;
 }
 
 static inline void *alloc_pgtable_page(int node)
@@ -1530,35 +1549,43 @@ static void iommu_disable_translation(struct intel_iommu *iommu)
 
 static int iommu_init_domains(struct intel_iommu *iommu)
 {
-       unsigned long ndomains;
-       unsigned long nlongs;
+       u32 ndomains, nlongs;
+       size_t size;
 
        ndomains = cap_ndoms(iommu->cap);
-       pr_debug("%s: Number of Domains supported <%ld>\n",
+       pr_debug("%s: Number of Domains supported <%d>\n",
                 iommu->name, ndomains);
        nlongs = BITS_TO_LONGS(ndomains);
 
        spin_lock_init(&iommu->lock);
 
-       /* TBD: there might be 64K domains,
-        * consider other allocation for future chip
-        */
        iommu->domain_ids = kcalloc(nlongs, sizeof(unsigned long), GFP_KERNEL);
        if (!iommu->domain_ids) {
                pr_err("%s: Allocating domain id array failed\n",
                       iommu->name);
                return -ENOMEM;
        }
-       iommu->domains = kcalloc(ndomains, sizeof(struct dmar_domain *),
-                       GFP_KERNEL);
-       if (!iommu->domains) {
+
+       size = ((ndomains >> 8) + 1) * sizeof(struct dmar_domain **);
+       iommu->domains = kzalloc(size, GFP_KERNEL);
+
+       if (iommu->domains) {
+               size = 256 * sizeof(struct dmar_domain *);
+               iommu->domains[0] = kzalloc(size, GFP_KERNEL);
+       }
+
+       if (!iommu->domains || !iommu->domains[0]) {
                pr_err("%s: Allocating domain array failed\n",
                       iommu->name);
                kfree(iommu->domain_ids);
+               kfree(iommu->domains);
                iommu->domain_ids = NULL;
+               iommu->domains    = NULL;
                return -ENOMEM;
        }
 
+
+
        /*
         * If Caching mode is set, then invalid translations are tagged
         * with domain-id 0, hence we need to pre-allocate it. We also
@@ -1600,6 +1627,11 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
 static void free_dmar_iommu(struct intel_iommu *iommu)
 {
        if ((iommu->domains) && (iommu->domain_ids)) {
+               int elems = (cap_ndoms(iommu->cap) >> 8) + 1;
+               int i;
+
+               for (i = 0; i < elems; i++)
+                       kfree(iommu->domains[i]);
                kfree(iommu->domains);
                kfree(iommu->domain_ids);
                iommu->domains = NULL;

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index d9a366d..6240063 100644 (file)
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -344,7 +344,7 @@ struct intel_iommu {
 
 #ifdef CONFIG_INTEL_IOMMU
        unsigned long   *domain_ids; /* bitmap of domains */
-       struct dmar_domain **domains; /* ptr to domains */
+       struct dmar_domain ***domains; /* ptr to domains */
        spinlock_t      lock; /* protect context, domain ids */
        struct root_entry *root_entry; /* virtual address */