[PATCH v6 18/25] iommu/ipmmu: Add an IOMMU_IDENTITIY_DOMAIN

[Jason Gunthorpe]

This brings back the ops->detach_dev() code that commit
1b932ceddd19 ("iommu: Remove detach_dev callbacks") deleted and turns it
into an IDENTITY domain.

Also reverts commit 584d334b1393 ("iommu/ipmmu-vmsa: Remove
ipmmu_utlb_disable()")

Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
---
 drivers/iommu/ipmmu-vmsa.c | 43 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 9f64c5c9f5b90a..de958e411a92e0 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -298,6 +298,18 @@ static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
 	mmu->utlb_ctx[utlb] = domain->context_id;
 }
 
+/*
+ * Disable MMU translation for the microTLB.
+ */
+static void ipmmu_utlb_disable(struct ipmmu_vmsa_domain *domain,
+			       unsigned int utlb)
+{
+	struct ipmmu_vmsa_device *mmu = domain->mmu;
+
+	ipmmu_imuctr_write(mmu, utlb, 0);
+	mmu->utlb_ctx[utlb] = IPMMU_CTX_INVALID;
+}
+
 static void ipmmu_tlb_flush_all(void *cookie)
 {
 	struct ipmmu_vmsa_domain *domain = cookie;
@@ -630,6 +642,36 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain,
 	return 0;
 }
 
+static int ipmmu_iommu_identity_attach(struct iommu_domain *identity_domain,
+				       struct device *dev)
+{
+	struct iommu_domain *io_domain = iommu_get_domain_for_dev(dev);
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct ipmmu_vmsa_domain *domain;
+	unsigned int i;
+
+	if (io_domain == identity_domain || !io_domain)
+		return 0;
+
+	domain = to_vmsa_domain(io_domain);
+	for (i = 0; i < fwspec->num_ids; ++i)
+		ipmmu_utlb_disable(domain, fwspec->ids[i]);
+
+	/*
+	 * TODO: Optimize by disabling the context when no device is attached.
+	 */
+	return 0;
+}
+
+static struct iommu_domain_ops ipmmu_iommu_identity_ops = {
+	.attach_dev = ipmmu_iommu_identity_attach,
+};
+
+static struct iommu_domain ipmmu_iommu_identity_domain = {
+	.type = IOMMU_DOMAIN_IDENTITY,
+	.ops = &ipmmu_iommu_identity_ops,
+};
+
 static int ipmmu_map(struct iommu_domain *io_domain, unsigned long iova,
 		     phys_addr_t paddr, size_t pgsize, size_t pgcount,
 		     int prot, gfp_t gfp, size_t *mapped)
@@ -848,6 +890,7 @@ static struct iommu_group *ipmmu_find_group(struct device *dev)
 }
 
 static const struct iommu_ops ipmmu_ops = {
+	.identity_domain = &ipmmu_iommu_identity_domain,
 	.domain_alloc = ipmmu_domain_alloc,
 	.probe_device = ipmmu_probe_device,
 	.release_device = ipmmu_release_device,
-- 
2.41.0