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Subject[PATCH v3 6/8] iommu/vt-d: Allow DMA domains to be allocated by iommu ops
Date
From: James Sewart <jamessewart@arista.com>

Allowing IOMMU_DOMAIN_DMA and IOMMU_DOMAIN_IDENTITY types of
domains to be allocated through iommu ops allows the default
domain of an iommu_group to be set. This delegates domains of
Intel IOMMU driver to the generic IOMMU layer.

Signed-off-by: James Sewart <jamessewart@arista.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 124 ++++++++++++++++++++++++++----------
1 file changed, 90 insertions(+), 34 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d2b51e045603..ec6ac39827ab 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -311,6 +311,12 @@ static int hw_pass_through = 1;
/* si_domain contains mulitple devices */
#define DOMAIN_FLAG_STATIC_IDENTITY (1 << 1)

+/*
+ * Domain managed externally, don't cleanup if it isn't attached
+ * to any devices.
+ */
+#define DOMAIN_FLAG_MANAGED_EXTERNALLY (1 << 2)
+
#define for_each_domain_iommu(idx, domain) \
for (idx = 0; idx < g_num_of_iommus; idx++) \
if (domain->iommu_refcnt[idx])
@@ -561,6 +567,11 @@ static inline int domain_type_is_vm_or_si(struct dmar_domain *domain)
DOMAIN_FLAG_STATIC_IDENTITY);
}

+static inline int domain_managed_externally(struct dmar_domain *domain)
+{
+ return domain->flags & DOMAIN_FLAG_MANAGED_EXTERNALLY;
+}
+
static inline int domain_pfn_supported(struct dmar_domain *domain,
unsigned long pfn)
{
@@ -1671,7 +1682,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)

__dmar_remove_one_dev_info(info);

- if (!domain_type_is_vm_or_si(domain)) {
+ if (!domain_managed_externally(domain)) {
/*
* The domain_exit() function can't be called under
* device_domain_lock, as it takes this lock itself.
@@ -2366,7 +2377,12 @@ static int domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
} else {
/* General domains only have one IOMMU */
iommu = domain_get_iommu(domain);
- __mapping_notify_one(iommu, domain, iov_pfn, nr_pages);
+ /*
+ * There's no associated iommu if domain hasn't been attached
+ * to any device yet.
+ */
+ if (iommu)
+ __mapping_notify_one(iommu, domain, iov_pfn, nr_pages);
}

return 0;
@@ -3406,12 +3422,9 @@ static int __init init_dmars(void)

check_tylersburg_isoch();

- if (iommu_identity_mapping) {
- ret = si_domain_init(hw_pass_through);
- if (ret)
- goto free_iommu;
- }
-
+ ret = si_domain_init(hw_pass_through);
+ if (ret)
+ goto free_iommu;

/*
* If we copied translations from a previous kernel in the kdump
@@ -4572,7 +4585,7 @@ static int device_notifier(struct notifier_block *nb,
return 0;

dmar_remove_one_dev_info(dev);
- if (!domain_type_is_vm_or_si(domain) &&
+ if (!domain_managed_externally(domain) &&
list_empty(&domain->devices))
domain_exit(domain);
} else if (action == BUS_NOTIFY_ADD_DEVICE) {
@@ -5038,33 +5051,52 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
{
struct dmar_domain *dmar_domain;
struct iommu_domain *domain;
+ int flags = DOMAIN_FLAG_MANAGED_EXTERNALLY;

- if (type != IOMMU_DOMAIN_UNMANAGED)
- return NULL;
+ switch (type) {
+ case IOMMU_DOMAIN_UNMANAGED:
+ flags |= DOMAIN_FLAG_VIRTUAL_MACHINE;
+ /* fall through */
+ case IOMMU_DOMAIN_DMA:
+ dmar_domain = alloc_domain(flags);
+ if (!dmar_domain)
+ return NULL;

- dmar_domain = alloc_domain(DOMAIN_FLAG_VIRTUAL_MACHINE);
- if (!dmar_domain) {
- pr_err("Can't allocate dmar_domain\n");
- return NULL;
- }
- if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
- pr_err("Domain initialization failed\n");
- domain_exit(dmar_domain);
+ if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
+ pr_err("Domain initialization failed\n");
+ domain_exit(dmar_domain);
+ return NULL;
+ }
+
+ if (type == IOMMU_DOMAIN_DMA &&
+ init_iova_flush_queue(&dmar_domain->iovad,
+ iommu_flush_iova, iova_entry_free)) {
+ pr_warn("iova flush queue initialization failed\n");
+ intel_iommu_strict = 1;
+ }
+
+ domain_update_iommu_cap(dmar_domain);
+ domain = &dmar_domain->domain;
+ domain->geometry.aperture_start = 0;
+ domain->geometry.aperture_end =
+ __DOMAIN_MAX_ADDR(dmar_domain->gaw);
+ domain->geometry.force_aperture = true;
+ break;
+ case IOMMU_DOMAIN_IDENTITY:
+ return &si_domain->domain;
+ default:
return NULL;
}
- domain_update_iommu_cap(dmar_domain);
-
- domain = &dmar_domain->domain;
- domain->geometry.aperture_start = 0;
- domain->geometry.aperture_end = __DOMAIN_MAX_ADDR(dmar_domain->gaw);
- domain->geometry.force_aperture = true;

- return domain;
+ return &dmar_domain->domain;
}

static void intel_iommu_domain_free(struct iommu_domain *domain)
{
- domain_exit(to_dmar_domain(domain));
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+
+ if (domain_managed_externally(dmar_domain))
+ domain_exit(dmar_domain);
}

/*
@@ -5240,13 +5272,33 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
{
int ret;

- if (device_is_rmrr_locked(dev)) {
- dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement. Contact your platform vendor.\n");
- return -EPERM;
- }
+ switch (domain->type) {
+ case IOMMU_DOMAIN_UNMANAGED:
+ if (device_is_rmrr_locked(dev)) {
+ dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement. Contact your platform vendor.\n");
+ return -EPERM;
+ }

- if (is_aux_domain(dev, domain))
- return -EPERM;
+ if (is_aux_domain(dev, domain))
+ return -EPERM;
+
+ break;
+ case IOMMU_DOMAIN_DMA:
+ if (intel_iommu_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY) {
+ dev_warn(dev, "Device requires identity domain\n");
+ return -EINVAL;
+ }
+ break;
+ case IOMMU_DOMAIN_IDENTITY:
+ if (intel_iommu_def_domain_type(dev) == IOMMU_DOMAIN_DMA) {
+ dev_warn(dev, "Device requires non-identity domain\n");
+ return -EINVAL;
+ }
+ break;
+ default:
+ dev_warn(dev, "Invalid domain type %u\n", domain->type);
+ return -EINVAL;
+ }

/* normally dev is not mapped */
if (unlikely(domain_context_mapped(dev))) {
@@ -5258,7 +5310,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
dmar_remove_one_dev_info(dev);
rcu_read_unlock();

- if (!domain_type_is_vm_or_si(old_domain) &&
+ if (!domain_managed_externally(old_domain) &&
list_empty(&old_domain->devices))
domain_exit(old_domain);
}
@@ -5307,6 +5359,10 @@ static int intel_iommu_map(struct iommu_domain *domain,
int prot = 0;
int ret;

+ /* Don't bother if hardware passthrough used. */
+ if (dmar_domain == si_domain && hw_pass_through)
+ return 0;
+
if (iommu_prot & IOMMU_READ)
prot |= DMA_PTE_READ;
if (iommu_prot & IOMMU_WRITE)
--
2.17.1
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