[PATCH v4 04/22] 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                | 31 +++++++++++-
 xen/arch/arm/domain_build.c          |  2 +
 xen/arch/arm/include/asm/viommu.h    | 70 ++++++++++++++++++++++++++++
 xen/drivers/passthrough/Kconfig      |  5 ++
 xen/drivers/passthrough/arm/Makefile |  1 +
 xen/drivers/passthrough/arm/viommu.c | 49 +++++++++++++++++++
 xen/include/public/arch-arm.h        |  6 ++-
 8 files changed, 164 insertions(+), 2 deletions(-)
 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 3f48f74226..f87437915e 100644
--- a/xen/arch/arm/dom0less-build.c
+++ b/xen/arch/arm/dom0less-build.c
@@ -23,6 +23,7 @@
 #include <asm/arm64/sve.h>
 #include <asm/domain_build.h>
 #include <asm/firmware/sci.h>
+#include <asm/viommu.h>
 #include <asm/grant_table.h>
 #include <asm/setup.h>
 
@@ -369,6 +370,7 @@ 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 ( domu_dt_sci_parse(node, d_cfg) )
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index a739dd157e..5c411a2310 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -33,6 +33,7 @@
 #include <asm/vgic.h>
 #include <asm/vpci.h>
 #include <asm/vpsci.h>
+#include <asm/viommu.h>
 #include <asm/vtimer.h>
 
 #include "vuart.h"
@@ -663,6 +664,21 @@ 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 sci_domain_sanitise_config(config);
 }
 
@@ -762,6 +778,9 @@ int arch_domain_create(struct domain *d,
     if ( (rc = sci_domain_init(d, config)) != 0 )
         goto fail;
 
+    if ( (rc = domain_viommu_init(d, config->arch.viommu_type)) != 0 )
+        goto fail;
+
     return 0;
 
 fail:
@@ -822,7 +841,8 @@ static void resume_ctx_reset(struct resume_info *ctx)
 void arch_domain_destroy(struct domain *d)
 {
     resume_ctx_reset(&d->arch.resume_ctx);
-
+    if ( viommu_relinquish_resources(d) )
+        printk(XENLOG_INFO "%pd: Domain vIOMMU teardown failed\n", d);
     tee_free_domain_ctx(d);
     /* IOMMU page table is shared with P2M, always call
      * iommu_domain_destroy() before p2m_final_teardown().
@@ -1058,6 +1078,7 @@ static int relinquish_memory(struct domain *d, struct 
page_list_head *list)
  */
 enum {
     PROG_pci = 1,
+    PROG_viommu,
     PROG_sci,
     PROG_tee,
     PROG_xen,
@@ -1105,6 +1126,14 @@ int domain_relinquish_resources(struct domain *d)
         if ( ret )
             return ret;
 #endif
+    /*
+     * PCI devices may rely on the vIOMMU, so its resources
+     * should be relinquished only after the PCI devices are released.
+     */
+    PROGRESS(viommu):
+        ret = viommu_relinquish_resources(d);
+        if (ret )
+            return ret;
 
     PROGRESS(sci):
         ret = sci_relinquish_resources(d);
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 72d5316180..cd2e09f005 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -36,6 +36,7 @@
 #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>
@@ -1964,6 +1965,7 @@ 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..95f82d9cf5
--- /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__
+
+#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
+     */
+    uint8_t viommu_type;
+};
+
+#ifdef CONFIG_ARM_VIRTUAL_IOMMU
+
+int domain_viommu_init(struct domain *d, uint8_t viommu_type);
+int viommu_relinquish_resources(struct domain *d);
+uint8_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, uint8_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_ARM_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..a92cfbea98 100644
--- a/xen/drivers/passthrough/Kconfig
+++ b/xen/drivers/passthrough/Kconfig
@@ -35,6 +35,11 @@ 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 ARM_VIRTUAL_IOMMU
+       bool "Virtual IOMMU Support (UNSUPPORTED)" if UNSUPPORTED
+       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..c3783188e3 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_ARM_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..0c0efd668e
--- /dev/null
+++ b/xen/drivers/passthrough/arm/viommu.c
@@ -0,0 +1,49 @@
+/* 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>
+
+/* Struct to hold the vIOMMU ops and vIOMMU type */
+static const struct viommu_desc __ro_after_init *cur_viommu;
+
+int domain_viommu_init(struct domain *d, uint8_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);
+}
+
+uint8_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 00de30b896..a1491f9cf7 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -334,6 +334,8 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t);
 #define XEN_DOMCTL_CONFIG_ARM_V8R_EL1_MSA_PMSA    1
 #define XEN_DOMCTL_CONFIG_ARM_V8R_EL1_MSA_VMSA    2
 
+#define XEN_DOMCTL_CONFIG_VIOMMU_NONE   0
+
 struct xen_arch_domainconfig {
     /* IN/OUT */
     uint8_t gic_version;
@@ -361,7 +363,9 @@ struct xen_arch_domainconfig {
     uint8_t arm_sci_type;
     /* IN */
     uint8_t v8r_el1_msa;
-    uint16_t pad;
+    /* IN */
+    uint8_t viommu_type;
+    uint8_t pad;
 };
 #endif /* __XEN__ || __XEN_TOOLS__ */
 
-- 
2.43.0