[PATCH v3 8/8] iommu/vt-d: Implement is_attach_deferred iommu ops entry

Lu Baolu
2019-04-29T02:09:25Z

As a domain is now attached to a device earlier, we should
implement the is_attach_deferred call-back and use it to
defer the domain attach from iommu driver init to device
driver init when iommu is pre-enabled in kdump kernel.

Suggested-by: Tom Murphy <tmurphy@arista.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index dd6abd554804..7e24f025f7a9 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -358,6 +358,8 @@ static void domain_context_clear(struct intel_iommu *iommu,
struct device *dev);
static int domain_detach_iommu(struct dmar_domain *domain,
struct intel_iommu *iommu);
+static int intel_iommu_attach_device(struct iommu_domain *domain,
+ struct device *dev);

#ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
int dmar_disabled = 0;
@@ -387,6 +389,7 @@ int intel_iommu_gfx_mapped;
EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);

#define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1))
+#define DEFER_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-2))
static DEFINE_SPINLOCK(device_domain_lock);
static LIST_HEAD(device_domain_list);

@@ -2404,8 +2407,18 @@ static struct dmar_domain *find_domain(struct device *dev)
{
struct device_domain_info *info;

+ if (unlikely(dev->archdata.iommu == DEFER_DEVICE_DOMAIN_INFO)) {
+ struct iommu_domain *domain;
+
+ dev->archdata.iommu = NULL;
+ domain = iommu_get_domain_for_dev(dev);
+ if (domain)
+ intel_iommu_attach_device(domain, dev);
+ }
+
/* No lock here, assumes no domain exit in normal case */
info = dev->archdata.iommu;
+
if (likely(info))
return info->domain;
return NULL;
@@ -5154,6 +5167,9 @@ static int intel_iommu_add_device(struct device *dev)

iommu_device_link(&iommu->iommu, dev);

+ if (translation_pre_enabled(iommu))
+ dev->archdata.iommu = DEFER_DEVICE_DOMAIN_INFO;
+
group = iommu_group_get_for_dev(dev);

if (IS_ERR(group))
@@ -5440,6 +5456,12 @@ intel_iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev)
dmar_domain->default_pasid : -EINVAL;
}

+static bool intel_iommu_is_attach_deferred(struct iommu_domain *domain,
+ struct device *dev)
+{
+ return dev->archdata.iommu == DEFER_DEVICE_DOMAIN_INFO;
+}
+
const struct iommu_ops intel_iommu_ops = {
.capable = intel_iommu_capable,
.domain_alloc = intel_iommu_domain_alloc,
@@ -5463,6 +5485,7 @@ const struct iommu_ops intel_iommu_ops = {
.dev_enable_feat = intel_iommu_dev_enable_feat,
.dev_disable_feat = intel_iommu_dev_disable_feat,
.def_domain_type = intel_iommu_def_domain_type,
+ .is_attach_deferred = intel_iommu_is_attach_deferred,
.pgsize_bitmap = INTEL_IOMMU_PGSIZES,
};

--
2.17.1