[PATCH 04/20] xen/arm: vIOMMU: add generic vIOMMU framework

[Milan Djokic <milan_djokic@xxxxxxxx>]

From: Rahul Singh <rahul.singh@xxxxxxx>

This patch adds basic framework for vIOMMU.

Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
Signed-off-by: Milan Djokic <milan_djokic@xxxxxxxx>
---
 xen/arch/arm/dom0less-build.c        |  2 +
 xen/arch/arm/domain.c                | 25 ++++++++++
 xen/arch/arm/domain_build.c          |  2 +
 xen/arch/arm/include/asm/viommu.h    | 70 ++++++++++++++++++++++++++++
 xen/drivers/passthrough/Kconfig      |  6 +++
 xen/drivers/passthrough/arm/Makefile |  1 +
 xen/drivers/passthrough/arm/viommu.c | 48 +++++++++++++++++++
 xen/include/public/arch-arm.h        |  4 ++
 8 files changed, 158 insertions(+)
 create mode 100644 xen/arch/arm/include/asm/viommu.h
 create mode 100644 xen/drivers/passthrough/arm/viommu.c

diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
index c8d07213e2..1fa6df214b 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -22,6 +22,7 @@
 
 #include <asm/arm64/sve.h>
 #include <asm/domain_build.h>
+#include <asm/viommu.h>
 #include <asm/grant_table.h>
 #include <asm/setup.h>
 
@@ -280,6 +281,7 @@ int __init arch_parse_dom0less_node(struct dt_device_node 
*node,
     uint32_t val;
 
     d_cfg->arch.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE;
+    d_cfg->arch.viommu_type = viommu_get_type();
     d_cfg->flags |= XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap;
 
     if ( !dt_property_read_u32(node, "nr_spis", &d_cfg->arch.nr_spis) )
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 310c578909..a66f71da17 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -27,6 +27,7 @@
 #include <asm/tee/tee.h>
 #include <asm/vfp.h>
 #include <asm/vgic.h>
+#include <asm/viommu.h>
 #include <asm/vtimer.h>
 
 #include "vpci.h"
@@ -699,6 +700,21 @@ int arch_sanitise_domain_config(struct 
xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( !(config->flags & XEN_DOMCTL_CDF_iommu) &&
+         config->arch.viommu_type != XEN_DOMCTL_CONFIG_VIOMMU_NONE )
+    {
+        dprintk(XENLOG_INFO,
+                "vIOMMU requested while iommu not enabled for domain\n");
+        return -EINVAL;
+    }
+
+    if ( config->arch.viommu_type != XEN_DOMCTL_CONFIG_VIOMMU_NONE )
+    {
+        dprintk(XENLOG_INFO,
+                "vIOMMU type requested not supported by the platform or 
Xen\n");
+        return -EINVAL;
+    }
+
     return 0;
 }
 
@@ -791,6 +807,9 @@ int arch_domain_create(struct domain *d,
     d->arch.sve_vl = config->arch.sve_vl;
 #endif
 
+    if ( (rc = domain_viommu_init(d, config->arch.viommu_type)) != 0 )
+        goto fail;
+
     return 0;
 
 fail:
@@ -1038,6 +1057,7 @@ static int relinquish_memory(struct domain *d, struct 
page_list_head *list)
 enum {
     PROG_pci = 1,
     PROG_tee,
+    PROG_viommu,
     PROG_xen,
     PROG_page,
     PROG_mapping,
@@ -1089,6 +1109,11 @@ int domain_relinquish_resources(struct domain *d)
         if (ret )
             return ret;
 
+    PROGRESS(viommu):
+        ret = viommu_relinquish_resources(d);
+        if (ret )
+            return ret;
+
     PROGRESS(xen):
         ret = relinquish_memory(d, &d->xenpage_list);
         if ( ret )
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 463ae4474d..50e4f5fee4 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -34,6 +34,7 @@
 #include <asm/arm64/sve.h>
 #include <asm/cpufeature.h>
 #include <asm/domain_build.h>
+#include <asm/viommu.h>
 #include <xen/event.h>
 
 #include <xen/irq.h>
@@ -2057,6 +2058,7 @@ void __init create_dom0(void)
     dom0_cfg.arch.nr_spis = VGIC_DEF_NR_SPIS;
     dom0_cfg.arch.tee_type = tee_get_type();
     dom0_cfg.max_vcpus = dom0_max_vcpus();
+    dom0_cfg.arch.viommu_type = viommu_get_type();
 
     if ( iommu_enabled )
         dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
diff --git a/xen/arch/arm/include/asm/viommu.h 
b/xen/arch/arm/include/asm/viommu.h
new file mode 100644
index 0000000000..7cd3818a12
--- /dev/null
+++ b/xen/arch/arm/include/asm/viommu.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
+#ifndef __ARCH_ARM_VIOMMU_H__
+#define __ARCH_ARM_VIOMMU_H__
+
+#ifdef CONFIG_VIRTUAL_IOMMU
+
+#include <xen/lib.h>
+#include <xen/types.h>
+#include <public/xen.h>
+
+struct viommu_ops {
+    /*
+     * Called during domain construction if toolstack requests to enable
+     * vIOMMU support.
+     */
+    int (*domain_init)(struct domain *d);
+
+    /*
+     * Called during domain destruction to free resources used by vIOMMU.
+     */
+    int (*relinquish_resources)(struct domain *d);
+};
+
+struct viommu_desc {
+    /* vIOMMU domains init/free operations described above. */
+    const struct viommu_ops *ops;
+
+    /*
+     * ID of vIOMMU. Corresponds to xen_arch_domainconfig.viommu_type.
+     * Should be one of XEN_DOMCTL_CONFIG_VIOMMU_xxx
+     */
+    uint16_t viommu_type;
+};
+
+int domain_viommu_init(struct domain *d, uint16_t viommu_type);
+int viommu_relinquish_resources(struct domain *d);
+uint16_t viommu_get_type(void);
+
+#else
+
+static inline uint8_t viommu_get_type(void)
+{
+    return XEN_DOMCTL_CONFIG_VIOMMU_NONE;
+}
+
+static inline int domain_viommu_init(struct domain *d, uint16_t viommu_type)
+{
+    if ( likely(viommu_type == XEN_DOMCTL_CONFIG_VIOMMU_NONE) )
+        return 0;
+
+    return -ENODEV;
+}
+
+static inline int viommu_relinquish_resources(struct domain *d)
+{
+    return 0;
+}
+
+#endif /* CONFIG_VIRTUAL_IOMMU */
+
+#endif /* __ARCH_ARM_VIOMMU_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/drivers/passthrough/Kconfig b/xen/drivers/passthrough/Kconfig
index b413c33a4c..fbd56eb990 100644
--- a/xen/drivers/passthrough/Kconfig
+++ b/xen/drivers/passthrough/Kconfig
@@ -35,6 +35,12 @@ config IPMMU_VMSA
          (H3 ES3.0, M3-W+, etc) or Gen4 SoCs which IPMMU hardware supports 
stage 2
          translation table format and is able to use CPU's P2M table as is.
 
+config VIRTUAL_IOMMU
+       bool "Virtual IOMMU Support (UNSUPPORTED)" if UNSUPPORTED
+       default n
+       help
+        Support virtual IOMMU infrastructure to implement vIOMMU.
+
 endif
 
 config AMD_IOMMU
diff --git a/xen/drivers/passthrough/arm/Makefile 
b/xen/drivers/passthrough/arm/Makefile
index c5fb3b58a5..4cc54f3f4d 100644
--- a/xen/drivers/passthrough/arm/Makefile
+++ b/xen/drivers/passthrough/arm/Makefile
@@ -2,3 +2,4 @@ obj-y += iommu.o iommu_helpers.o iommu_fwspec.o
 obj-$(CONFIG_ARM_SMMU) += smmu.o
 obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
 obj-$(CONFIG_ARM_SMMU_V3) += smmu-v3.o
+obj-$(CONFIG_VIRTUAL_IOMMU) += viommu.o
diff --git a/xen/drivers/passthrough/arm/viommu.c 
b/xen/drivers/passthrough/arm/viommu.c
new file mode 100644
index 0000000000..7ab6061e34
--- /dev/null
+++ b/xen/drivers/passthrough/arm/viommu.c
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
+
+#include <xen/errno.h>
+#include <xen/init.h>
+#include <xen/types.h>
+
+#include <asm/viommu.h>
+
+const struct viommu_desc __read_mostly *cur_viommu;
+
+int domain_viommu_init(struct domain *d, uint16_t viommu_type)
+{
+    if ( viommu_type == XEN_DOMCTL_CONFIG_VIOMMU_NONE )
+        return 0;
+
+    if ( !cur_viommu )
+        return -ENODEV;
+
+    if ( cur_viommu->viommu_type != viommu_type )
+        return -EINVAL;
+
+    return cur_viommu->ops->domain_init(d);
+}
+
+int viommu_relinquish_resources(struct domain *d)
+{
+    if ( !cur_viommu )
+        return 0;
+
+    return cur_viommu->ops->relinquish_resources(d);
+}
+
+uint16_t viommu_get_type(void)
+{
+    if ( !cur_viommu )
+        return XEN_DOMCTL_CONFIG_VIOMMU_NONE;
+
+    return cur_viommu->viommu_type;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index e2412a1747..0a155fe615 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -327,12 +327,16 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t);
 #define XEN_DOMCTL_CONFIG_TEE_OPTEE     1
 #define XEN_DOMCTL_CONFIG_TEE_FFA       2
 
+#define XEN_DOMCTL_CONFIG_VIOMMU_NONE   0
+
 struct xen_arch_domainconfig {
     /* IN/OUT */
     uint8_t gic_version;
     /* IN - Contains SVE vector length divided by 128 */
     uint8_t sve_vl;
     /* IN */
+    uint8_t viommu_type;
+    /* IN */
     uint16_t tee_type;
     /* IN */
     uint32_t nr_spis;
-- 
2.43.0