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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>
This commit is contained in:
Joerg Roedel 2015-07-21 10:41:21 +02:00
parent 9452d5bfe5
commit 8bf478163e
2 changed files with 44 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
drivers/iommu/intel-iommu.c
View File

@ -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;

2
include/linux/intel-iommu.h
View File

@ -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 */