[PATCH v4 02/11] xen: introduce CDF_directmap

[Penny Zheng <penny.zheng@xxxxxxx>]

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>

This commit introduces a new arm-specific flag CDF_directmap to specify
that a domain should have its memory direct-map(guest physical address
== physical address) at domain creation.

Also, add a directmap flag under struct arch_domain and use it to
reimplement is_domain_direct_mapped.

For now, direct-map is only available when statically allocated memory is
used for the domain, that is, "xen,static-mem" must be also defined in the
domain configuration.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
---
v2 changes
- remove the introduce of internal flag
- remove flag direct_map since we already store this flag in d->options
- Refine is_domain_direct_mapped to check whether the flag
XEN_DOMCTL_CDF_directmap is set
- reword "1:1 direct-map" to just "direct-map"
---
v3 changes
- move flag back to xen/include/xen/domain.h, to let it be only available for
domain created by XEN.
- name it with extra "INTERNAL" and add comments to warn developers not
to accidently use its bitfield when introducing new XEN_DOMCTL_CDF_xxx flag.
- reject this flag in x86'es arch_sanitise_domain_config()
---
v4 changes
- introduce new internal flag CDF_directmap
- add a directmap flag under struct arch_domain and use it to
reimplement is_domain_direct_mapped.
- expand arch_domain_create to include internal-only parameter "const unsigned
int flags" for domain creation
---
 docs/misc/arm/device-tree/booting.txt |  6 ++++++
 xen/arch/arm/domain.c                 |  5 ++++-
 xen/arch/arm/domain_build.c           | 14 ++++++++++++--
 xen/arch/arm/include/asm/domain.h     |  5 +++--
 xen/arch/x86/domain.c                 |  3 ++-
 xen/common/domain.c                   |  2 +-
 xen/include/xen/domain.h              |  5 ++++-
 7 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/docs/misc/arm/device-tree/booting.txt 
b/docs/misc/arm/device-tree/booting.txt
index 71895663a4..a94125394e 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -182,6 +182,12 @@ with the following properties:
     Both #address-cells and #size-cells need to be specified because
     both sub-nodes (described shortly) have reg properties.
 
+- direct-map
+
+    Only available when statically allocated memory is used for the domain.
+    An empty property to request the memory of the domain to be
+    direct-map (guest physical address == physical address).
+
 Under the "xen,domain" compatible node, one or more sub-nodes are present
 for the DomU kernel and ramdisk.
 
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 92a6c509e5..fa18dfa544 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -692,7 +692,8 @@ int arch_sanitise_domain_config(struct 
xen_domctl_createdomain *config)
 }
 
 int arch_domain_create(struct domain *d,
-                       struct xen_domctl_createdomain *config)
+                       struct xen_domctl_createdomain *config,
+                       const unsigned int flags)
 {
     int rc, count = 0;
 
@@ -708,6 +709,8 @@ int arch_domain_create(struct domain *d,
     ioreq_domain_init(d);
 #endif
 
+    d->arch.directmap = flags & CDF_directmap;
+
     /* p2m_init relies on some value initialized by the IOMMU subsystem */
     if ( (rc = iommu_domain_init(d, config->iommu_opts)) != 0 )
         goto fail;
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 0fab8604de..9b1a5e38d3 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -3029,10 +3029,20 @@ void __init create_domUs(void)
             .max_maptrack_frames = -1,
             .grant_opts = XEN_DOMCTL_GRANT_version(opt_gnttab_max_version),
         };
+        unsigned int flags = 0U;
 
         if ( !dt_device_is_compatible(node, "xen,domain") )
             continue;
 
+        if ( dt_property_read_bool(node, "direct-map") )
+        {
+            if ( !IS_ENABLED(CONFIG_STATIC_MEMORY) )
+                panic("direct-map is not valid for domain %s without 
CONFIG_STATIC_MEMORY\n",
+                      dt_node_name(node));
+
+            flags |= CDF_directmap;
+        }
+
         if ( !dt_property_read_u32(node, "cpus", &d_cfg.max_vcpus) )
             panic("Missing property 'cpus' for domain %s\n",
                   dt_node_name(node));
@@ -3058,7 +3068,7 @@ void __init create_domUs(void)
          * very important to use the pre-increment operator to call
          * domain_create() with a domid > 0. (domid == 0 is reserved for Dom0)
          */
-        d = domain_create(++max_init_domid, &d_cfg, 0);
+        d = domain_create(++max_init_domid, &d_cfg, flags);
         if ( IS_ERR(d) )
             panic("Error creating domain %s\n", dt_node_name(node));
 
@@ -3160,7 +3170,7 @@ void __init create_dom0(void)
     if ( iommu_enabled )
         dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
 
-    dom0 = domain_create(0, &dom0_cfg, CDF_privileged);
+    dom0 = domain_create(0, &dom0_cfg, CDF_privileged | CDF_directmap);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
         panic("Error creating domain 0\n");
 
diff --git a/xen/arch/arm/include/asm/domain.h 
b/xen/arch/arm/include/asm/domain.h
index 9b3647587a..cb37ce89ec 100644
--- a/xen/arch/arm/include/asm/domain.h
+++ b/xen/arch/arm/include/asm/domain.h
@@ -29,8 +29,7 @@ enum domain_type {
 #define is_64bit_domain(d) (0)
 #endif
 
-/* The hardware domain has always its memory direct mapped. */
-#define is_domain_direct_mapped(d) is_hardware_domain(d)
+#define is_domain_direct_mapped(d) (d->arch.directmap)
 
 struct vtimer {
     struct vcpu *v;
@@ -89,6 +88,8 @@ struct arch_domain
 #ifdef CONFIG_TEE
     void *tee;
 #endif
+
+    bool directmap;
 }  __cacheline_aligned;
 
 struct arch_vcpu
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index ef1812dc14..f6de7a9697 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -722,7 +722,8 @@ static bool emulation_flags_ok(const struct domain *d, 
uint32_t emflags)
 }
 
 int arch_domain_create(struct domain *d,
-                       struct xen_domctl_createdomain *config)
+                       struct xen_domctl_createdomain *config,
+                       const unsigned int flags)
 {
     bool paging_initialised = false;
     uint32_t emflags;
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 023c89c0ea..c9bcd77e00 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -659,7 +659,7 @@ struct domain *domain_create(domid_t domid,
         radix_tree_init(&d->pirq_tree);
     }
 
-    if ( (err = arch_domain_create(d, config)) != 0 )
+    if ( (err = arch_domain_create(d, config, flags)) != 0 )
         goto fail;
     init_status |= INIT_arch;
 
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index cfb0b47f13..2f1e172957 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -31,6 +31,8 @@ void arch_get_domain_info(const struct domain *d,
 /* CDF_* constant. Internal flags for domain creation. */
 /* Is this a privileged domain? */
 #define CDF_privileged           (1U << 0)
+/* Should domain memory be directly mapped? */
+#define CDF_directmap            (1U << 1)
 
 /*
  * Arch-specifics.
@@ -65,7 +67,8 @@ int map_vcpu_info(struct vcpu *v, unsigned long gfn, unsigned 
offset);
 void unmap_vcpu_info(struct vcpu *v);
 
 int arch_domain_create(struct domain *d,
-                       struct xen_domctl_createdomain *config);
+                       struct xen_domctl_createdomain *config,
+                       const unsigned int flags);
 
 void arch_domain_destroy(struct domain *d);
 
-- 
2.25.1