[RFC PATCH v2 51/58] iommu/arm-smmu-v3-kvm: Support PASID operations

[Mostafa Saleh <smostafa@google.com>]

Add support for set_dev_pasid and remove_dev_pasid, the hypervisor
already supports pasid, so we just need to forward it in the
hypercalls in addition to proper tracking of domains per master.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c   | 58 +++++++++++++++----
 1 file changed, 48 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
index 82f0191b222c..cbcd8a75d562 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -29,7 +29,8 @@ struct host_arm_smmu_device {
 struct kvm_arm_smmu_master {
 	struct arm_smmu_device		*smmu;
 	struct device			*dev;
-	struct kvm_arm_smmu_domain      *domain;
+	struct xarray			domains;
+	u32				ssid_bits;
 };
 
 struct kvm_arm_smmu_domain {
@@ -119,6 +120,10 @@ static struct iommu_device *kvm_arm_smmu_probe_device(struct device *dev)
 
 	master->dev = dev;
 	master->smmu = smmu;
+
+	device_property_read_u32(dev, "pasid-num-bits", &master->ssid_bits);
+	master->ssid_bits = min(smmu->ssid_bits, master->ssid_bits);
+	xa_init(&master->domains);
 	dev_iommu_priv_set(dev, master);
 
 	return &smmu->iommu;
@@ -235,13 +240,14 @@ static void kvm_arm_smmu_domain_free(struct iommu_domain *domain)
 	kfree(kvm_smmu_domain);
 }
 
-static int kvm_arm_smmu_detach_dev(struct host_arm_smmu_device *host_smmu,
-				   struct kvm_arm_smmu_master *master)
+static int kvm_arm_smmu_detach_dev_pasid(struct host_arm_smmu_device *host_smmu,
+					 struct kvm_arm_smmu_master *master,
+					 ioasid_t pasid)
 {
 	int i, ret;
 	struct arm_smmu_device *smmu = &host_smmu->smmu;
 	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
-	struct kvm_arm_smmu_domain *domain = master->domain;
+	struct kvm_arm_smmu_domain *domain = xa_load(&master->domains, pasid);
 
 	if (!domain)
 		return 0;
@@ -250,7 +256,7 @@ static int kvm_arm_smmu_detach_dev(struct host_arm_smmu_device *host_smmu,
 		int sid = fwspec->ids[i];
 
 		ret = kvm_call_hyp_nvhe(__pkvm_host_iommu_detach_dev,
-					host_smmu->id, domain->id, sid, 0);
+					host_smmu->id, domain->id, sid, pasid);
 		if (ret) {
 			dev_err(smmu->dev, "cannot detach device %s (0x%x): %d\n",
 				dev_name(master->dev), sid, ret);
@@ -258,22 +264,39 @@ static int kvm_arm_smmu_detach_dev(struct host_arm_smmu_device *host_smmu,
 		}
 	}
 
-	master->domain = NULL;
+	xa_erase(&master->domains, pasid);
 
 	return ret;
 }
 
+static int kvm_arm_smmu_detach_dev(struct host_arm_smmu_device *host_smmu,
+				   struct kvm_arm_smmu_master *master)
+{
+	return kvm_arm_smmu_detach_dev_pasid(host_smmu, master, 0);
+}
+
+static void kvm_arm_smmu_remove_dev_pasid(struct device *dev, ioasid_t pasid,
+					  struct iommu_domain *domain)
+{
+	struct kvm_arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct host_arm_smmu_device *host_smmu = smmu_to_host(master->smmu);
+
+	kvm_arm_smmu_detach_dev_pasid(host_smmu, master, pasid);
+}
+
 static void kvm_arm_smmu_release_device(struct device *dev)
 {
 	struct kvm_arm_smmu_master *master = dev_iommu_priv_get(dev);
 	struct host_arm_smmu_device *host_smmu = smmu_to_host(master->smmu);
 
 	kvm_arm_smmu_detach_dev(host_smmu, master);
+	xa_destroy(&master->domains);
 	kfree(master);
 	iommu_fwspec_free(dev);
 }
 
-static int kvm_arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
+static int kvm_arm_smmu_set_dev_pasid(struct iommu_domain *domain,
+				      struct device *dev, ioasid_t pasid)
 {
 	int i, ret;
 	struct arm_smmu_device *smmu;
@@ -288,7 +311,7 @@ static int kvm_arm_smmu_attach_dev(struct iommu_domain *domain, struct device *d
 	smmu = master->smmu;
 	host_smmu = smmu_to_host(smmu);
 
-	ret = kvm_arm_smmu_detach_dev(host_smmu, master);
+	ret = kvm_arm_smmu_detach_dev_pasid(host_smmu, master, pasid);
 	if (ret)
 		return ret;
 
@@ -303,14 +326,14 @@ static int kvm_arm_smmu_attach_dev(struct iommu_domain *domain, struct device *d
 
 		ret = kvm_call_hyp_nvhe_mc(__pkvm_host_iommu_attach_dev,
 					   host_smmu->id, kvm_smmu_domain->id,
-					   sid, 0, 0);
+					   sid, pasid, master->ssid_bits);
 		if (ret) {
 			dev_err(smmu->dev, "cannot attach device %s (0x%x): %d\n",
 				dev_name(dev), sid, ret);
 			goto out_ret;
 		}
 	}
-	master->domain = kvm_smmu_domain;
+	ret = xa_insert(&master->domains, pasid, kvm_smmu_domain, GFP_KERNEL);
 
 out_ret:
 	if (ret)
@@ -318,6 +341,19 @@ static int kvm_arm_smmu_attach_dev(struct iommu_domain *domain, struct device *d
 	return ret;
 }
 
+static int kvm_arm_smmu_attach_dev(struct iommu_domain *domain,
+				   struct device *dev)
+{
+	struct kvm_arm_smmu_master *master = dev_iommu_priv_get(dev);
+	unsigned long pasid = 0;
+
+	/* All pasids must be removed first. */
+	if (xa_find_after(&master->domains, &pasid, ULONG_MAX, XA_PRESENT))
+		return -EBUSY;
+
+	return kvm_arm_smmu_set_dev_pasid(domain, dev, 0);
+}
+
 static bool kvm_arm_smmu_capable(struct device *dev, enum iommu_cap cap)
 {
 	struct kvm_arm_smmu_master *master = dev_iommu_priv_get(dev);
@@ -409,6 +445,7 @@ static struct iommu_ops kvm_arm_smmu_ops = {
 	.release_device		= kvm_arm_smmu_release_device,
 	.domain_alloc		= kvm_arm_smmu_domain_alloc,
 	.pgsize_bitmap		= -1UL,
+	.remove_dev_pasid	= kvm_arm_smmu_remove_dev_pasid,
 	.owner			= THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= kvm_arm_smmu_attach_dev,
@@ -416,6 +453,7 @@ static struct iommu_ops kvm_arm_smmu_ops = {
 		.map_pages	= kvm_arm_smmu_map_pages,
 		.unmap_pages	= kvm_arm_smmu_unmap_pages,
 		.iova_to_phys	= kvm_arm_smmu_iova_to_phys,
+		.set_dev_pasid	= kvm_arm_smmu_set_dev_pasid,
 	}
 };
 
-- 
2.47.0.338.g60cca15819-goog