[PATCH v5 07/24] iommu/amd: Add support for AMD vIOMMU VF MMIO region

[Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>]

The AMD vIOMMU virtualizes guest MMIO registers at the 3rd 4K region.
This is achieved using the iommufd_viommu_alloc_mmap().

Copy struct iommu_viommu_amd from and to userspace so the VF-MMIO
mmap offset is validated and returned on vIOMMU alloc.

Return -EINVAL if the VF-MMIO page_base is zero so mmap is not
registered at physical address 0.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Co-developed-by: Vasant Hegde <Vasant.Hegde@amd.com>
Signed-off-by: Vasant Hegde <Vasant.Hegde@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/amd_iommu_types.h |  3 +++
 drivers/iommu/amd/amd_viommu.h      |  7 +++++
 drivers/iommu/amd/iommufd.c         | 41 ++++++++++++++++++++++++++++-
 drivers/iommu/amd/viommu.c          | 12 +++++++++
 4 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index c2257d48e222..3aaaf69a1e7d 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -532,6 +532,9 @@ struct amd_iommu_viommu {
 	 * Indexed by guest domain ID.
 	 */
 	struct xarray gdomid_array;
+
+	/* Offset for mmap() of guest VF MMIO; set after iommufd_viommu_alloc_mmap(). */
+	unsigned long vfmmio_mmap_offset;
 };
 
 /*
diff --git a/drivers/iommu/amd/amd_viommu.h b/drivers/iommu/amd/amd_viommu.h
index e5fbea666e01..276f2126290f 100644
--- a/drivers/iommu/amd/amd_viommu.h
+++ b/drivers/iommu/amd/amd_viommu.h
@@ -14,6 +14,8 @@ int amd_viommu_init(struct amd_iommu *iommu);
 
 void __init amd_viommu_uninit(struct amd_iommu *iommu);
 
+u64 amd_viommu_get_vfmmio_addr(struct amd_iommu *iommu, u16 gid);
+
 #else
 
 /*
@@ -30,6 +32,11 @@ static inline void amd_viommu_uninit(struct amd_iommu *iommu)
 {
 }
 
+static inline u64 amd_viommu_get_vfmmio_addr(struct amd_iommu *iommu, u16 gid)
+{
+	return 0;
+}
+
 #endif /* CONFIG_AMD_IOMMU_IOMMUFD */
 
 #endif /* AMD_VIOMMU_H */
diff --git a/drivers/iommu/amd/iommufd.c b/drivers/iommu/amd/iommufd.c
index 69a0e61bf83d..7f358e57efde 100644
--- a/drivers/iommu/amd/iommufd.c
+++ b/drivers/iommu/amd/iommufd.c
@@ -7,6 +7,7 @@
 
 #include "iommufd.h"
 #include "amd_iommu.h"
+#include "amd_viommu.h"
 #include "amd_iommu_types.h"
 
 static const struct iommufd_viommu_ops amd_viommu_ops;
@@ -51,6 +52,8 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 {
 	int ret;
 	unsigned long flags;
+	phys_addr_t page_base;
+	struct iommu_viommu_amd data = {};
 	struct protection_domain *pdom = to_pdomain(parent);
 	struct amd_iommu_viommu *aviommu = container_of(viommu, struct amd_iommu_viommu, core);
 	struct amd_iommu *iommu = container_of(viommu->iommu_dev, struct amd_iommu, iommu);
@@ -58,14 +61,43 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 	if (!amd_iommu_viommu_enabled(iommu))
 		return -EOPNOTSUPP;
 
+	if (!user_data)
+		return -EINVAL;
+
+	ret = iommu_copy_struct_from_user(&data, user_data,
+					  IOMMU_VIOMMU_TYPE_AMD,
+					  out_vfmmio_mmap_offset);
+	if (ret)
+		return ret;
+
 	xa_init_flags(&aviommu->gdomid_array, XA_FLAGS_ALLOC1);
 	aviommu->parent = pdom;
 
 	ret = amd_iommu_gid_alloc(iommu);
 	if (ret < 0)
-		return ret;
+		goto err_gid;
 	aviommu->gid = ret;
 
+	page_base = amd_viommu_get_vfmmio_addr(iommu, aviommu->gid);
+	if (!page_base) {
+		ret = -EINVAL;
+		goto err_mmap;
+	}
+
+	ret = iommufd_viommu_alloc_mmap(&aviommu->core,
+					page_base, SZ_4K,
+					&aviommu->vfmmio_mmap_offset);
+	if (ret)
+		goto err_mmap;
+
+	data.out_vfmmio_mmap_offset = aviommu->vfmmio_mmap_offset;
+
+	ret = iommu_copy_struct_to_user(user_data, &data,
+					IOMMU_VIOMMU_TYPE_AMD,
+					out_vfmmio_mmap_offset);
+	if (ret)
+		goto err_init;
+
 	viommu->ops = &amd_viommu_ops;
 
 	spin_lock_irqsave(&pdom->lock, flags);
@@ -73,6 +105,12 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 	spin_unlock_irqrestore(&pdom->lock, flags);
 
 	return 0;
+err_init:
+	iommufd_viommu_destroy_mmap(&aviommu->core, aviommu->vfmmio_mmap_offset);
+err_mmap:
+	amd_iommu_gid_free(iommu, aviommu->gid);
+err_gid:
+	return ret;
 }
 
 static void amd_iommufd_viommu_destroy(struct iommufd_viommu *viommu)
@@ -88,6 +126,7 @@ static void amd_iommufd_viommu_destroy(struct iommufd_viommu *viommu)
 	list_del(&aviommu->pdom_list);
 	spin_unlock_irqrestore(&pdom->lock, flags);
 	xa_destroy(&aviommu->gdomid_array);
+	iommufd_viommu_destroy_mmap(&aviommu->core, aviommu->vfmmio_mmap_offset);
 	amd_iommu_gid_free(iommu, aviommu->gid);
 }
 
diff --git a/drivers/iommu/amd/viommu.c b/drivers/iommu/amd/viommu.c
index 7e6c4412ff20..c9207ed47fb6 100644
--- a/drivers/iommu/amd/viommu.c
+++ b/drivers/iommu/amd/viommu.c
@@ -110,6 +110,18 @@ static int __init viommu_vf_vfcntl_init(struct amd_iommu *iommu)
 	return -ENOMEM;
 }
 
+/*
+ * Returns VF MMIO BAR offset for the given guest ID which will be
+ * mapped to guest vIOMMU 3rd 4K MMIO address
+ */
+u64 amd_viommu_get_vfmmio_addr(struct amd_iommu *iommu, u16 gid)
+{
+	if (WARN_ON(!iommu->vf_base_phys || gid > VIOMMU_MAX_GID))
+		return 0;
+
+	return iommu->vf_base_phys + gid * VIOMMU_VF_MMIO_ENTRY_SIZE;
+}
+
 int __init amd_viommu_init(struct amd_iommu *iommu)
 {
 	int ret;
-- 
2.34.1