[RFC PATCH v2 43/58] iommu/arm-smmu-v3-kvm: Pass a list of SMMU devices to the hypervisor

[Mostafa Saleh]

From: Jean-Philippe Brucker <jean-philippe at linaro.org>

Build a list of devices and donate the page to the hypervisor. At this
point the host is trusted and this would be a good opportunity to
provide more information about the system. For example, which devices
are owned by the host (perhaps via the VMID and SW bits in the stream
table, although we populate the stream table lazily at the moment.)

Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
Signed-off-by: Mostafa Saleh <smostafa at google.com>
---
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c   | 128 +++++++++++++++++-
 1 file changed, 126 insertions(+), 2 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 8cea33d15e08..e2d9bd97ddc5 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
@@ -15,9 +15,73 @@
 
 extern struct kvm_iommu_ops kvm_nvhe_sym(smmu_ops);
 
+struct host_arm_smmu_device {
+	struct arm_smmu_device		smmu;
+	pkvm_handle_t			id;
+};
+
+#define smmu_to_host(_smmu) \
+	container_of(_smmu, struct host_arm_smmu_device, smmu);
+
+static size_t				kvm_arm_smmu_cur;
+static size_t				kvm_arm_smmu_count;
+static struct hyp_arm_smmu_v3_device	*kvm_arm_smmu_array;
+
 static int kvm_arm_smmu_probe(struct platform_device *pdev)
 {
-	return -ENOSYS;
+	int ret;
+	size_t size;
+	phys_addr_t ioaddr;
+	struct resource *res;
+	struct arm_smmu_device *smmu;
+	struct device *dev = &pdev->dev;
+	struct host_arm_smmu_device *host_smmu;
+	struct hyp_arm_smmu_v3_device *hyp_smmu;
+
+	if (kvm_arm_smmu_cur >= kvm_arm_smmu_count)
+		return -ENOSPC;
+
+	hyp_smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
+
+	host_smmu = devm_kzalloc(dev, sizeof(*host_smmu), GFP_KERNEL);
+	if (!host_smmu)
+		return -ENOMEM;
+
+	smmu = &host_smmu->smmu;
+	smmu->dev = dev;
+
+	ret = arm_smmu_fw_probe(pdev, smmu);
+	if (ret)
+		return ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	size = resource_size(res);
+	if (size < SZ_128K) {
+		dev_err(dev, "unsupported MMIO region size (%pr)\n", res);
+		return -EINVAL;
+	}
+	ioaddr = res->start;
+	host_smmu->id = kvm_arm_smmu_cur;
+
+	smmu->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(smmu->base))
+		return PTR_ERR(smmu->base);
+
+	ret = arm_smmu_device_hw_probe(smmu);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, smmu);
+
+	/* Hypervisor parameters */
+	hyp_smmu->pgsize_bitmap = smmu->pgsize_bitmap;
+	hyp_smmu->oas = smmu->oas;
+	hyp_smmu->ias = smmu->ias;
+	hyp_smmu->mmio_addr = ioaddr;
+	hyp_smmu->mmio_size = size;
+	kvm_arm_smmu_cur++;
+
+	return arm_smmu_register_iommu(smmu, &kvm_arm_smmu_ops, ioaddr);
 }
 
 static void kvm_arm_smmu_remove(struct platform_device *pdev)
@@ -37,9 +101,69 @@ static struct platform_driver kvm_arm_smmu_driver = {
 	.remove = kvm_arm_smmu_remove,
 };
 
+static int kvm_arm_smmu_array_alloc(void)
+{
+	int smmu_order;
+	struct device_node *np;
+
+	kvm_arm_smmu_count = 0;
+	for_each_compatible_node(np, NULL, "arm,smmu-v3")
+		kvm_arm_smmu_count++;
+
+	if (!kvm_arm_smmu_count)
+		return 0;
+
+	/* Allocate the parameter list shared with the hypervisor */
+	smmu_order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
+	kvm_arm_smmu_array = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+						      smmu_order);
+	if (!kvm_arm_smmu_array)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void kvm_arm_smmu_array_free(void)
+{
+	int order;
+
+	order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
+	free_pages((unsigned long)kvm_arm_smmu_array, order);
+}
+
 static int kvm_arm_smmu_v3_init_drv(void)
 {
-	return platform_driver_probe(&kvm_arm_smmu_driver, kvm_arm_smmu_probe);
+	int ret;
+
+	/*
+	 * Check whether any device owned by the host is behind an SMMU.
+	 */
+	ret = kvm_arm_smmu_array_alloc();
+	if (ret || !kvm_arm_smmu_count)
+		return ret;
+
+	ret = platform_driver_probe(&kvm_arm_smmu_driver, kvm_arm_smmu_probe);
+	if (ret)
+		goto err_free;
+
+	if (kvm_arm_smmu_cur != kvm_arm_smmu_count) {
+		/* A device exists but failed to probe */
+		ret = -EUNATCH;
+		goto err_free;
+	}
+
+	/*
+	 * These variables are stored in the nVHE image, and won't be accessible
+	 * after KVM initialization. Ownership of kvm_arm_smmu_array will be
+	 * transferred to the hypervisor as well.
+	 */
+	kvm_hyp_arm_smmu_v3_smmus = kvm_arm_smmu_array;
+	kvm_hyp_arm_smmu_v3_count = kvm_arm_smmu_count;
+	return 0;
+
+err_free:
+	kvm_arm_smmu_array_free();
+	return ret;
 }
 
 static void kvm_arm_smmu_v3_remove_drv(void)
-- 
2.47.0.338.g60cca15819-goog