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Commit 8bf47816 authored by Joerg Roedel's avatar Joerg Roedel
Browse files

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: default avatarJoerg Roedel <jroedel@suse.de>
parent 9452d5bf

drivers/iommu/intel-iommu.c

+43 −11
Original line number Diff line number Diff line
@@ -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;

include/linux/intel-iommu.h

+1 −1
Original line number Diff line number Diff line
@@ -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 */