[PATCH v3 5/9] xen/arm: add support for cache coloring configuration via device-tree

[Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>]

This commit adds the "colors" Device Tree attribute that can be used for
DomUs and Dom0less color configurations. The syntax is the same used
for every color config.

Based on original work from: Luca Miccio <lucmiccio@xxxxxxxxx>

Signed-off-by: Carlo Nonato <carlo.nonato@xxxxxxxxxxxxxxx>
Signed-off-by: Marco Solieri <marco.solieri@xxxxxxxxxxxxxxx>
---
 docs/misc/arm/cache-coloring.rst      | 45 +++++++++++++++++++++++++++
 docs/misc/arm/device-tree/booting.txt |  4 +++
 xen/arch/arm/coloring.c               | 17 ++++++++++
 xen/arch/arm/domain_build.c           | 13 ++++++++
 xen/arch/arm/include/asm/coloring.h   |  5 +++
 5 files changed, 84 insertions(+)

diff --git a/docs/misc/arm/cache-coloring.rst b/docs/misc/arm/cache-coloring.rst
index e8ee8fafde..dd2e851a26 100644
--- a/docs/misc/arm/cache-coloring.rst
+++ b/docs/misc/arm/cache-coloring.rst
@@ -114,6 +114,51 @@ LLC way size (as previously discussed) and Dom0 colors can 
be set using the
 appropriate command line parameters. See the relevant documentation in
 "docs/misc/xen-command-line.pandoc".
 
+DomUs colors can be set either in the xl configuration file (relative
+documentation at "docs/man/xl.cfg.pod.5.in") or via Device Tree, also for
+Dom0less configurations, as in the following example:
+
+.. raw:: html
+
+    <pre>
+        xen,xen-bootargs = "console=dtuart dtuart=serial0 dom0_mem=1G 
dom0_max_vcpus=1 sched=null llc-way-size=64K xen-colors=0-1 dom0-colors=2-6";
+        xen,dom0-bootargs "console=hvc0 earlycon=xen earlyprintk=xen 
root=/dev/ram0"
+
+        dom0 {
+            compatible = "xen,linux-zimage" "xen,multiboot-module";
+            reg = <0x0 0x1000000 0x0 15858176>;
+        };
+
+        dom0-ramdisk {
+            compatible = "xen,linux-initrd" "xen,multiboot-module";
+            reg = <0x0 0x2000000 0x0 20638062>;
+        };
+
+        domU0 {
+            #address-cells = <0x1>;
+            #size-cells = <0x1>;
+            compatible = "xen,domain";
+            memory = <0x0 0x40000>;
+            colors = "4-8,10,11,12";
+            cpus = <0x1>;
+            vpl011 = <0x1>;
+
+            module@2000000 {
+                compatible = "multiboot,kernel", "multiboot,module";
+                reg = <0x2000000 0xffffff>;
+                bootargs = "console=ttyAMA0";
+            };
+
+            module@30000000 {
+                compatible = "multiboot,ramdisk", "multiboot,module";
+                reg = <0x3000000 0xffffff>;
+            };
+        };
+    </pre>
+
+Please refer to the relative documentation in
+"docs/misc/arm/device-tree/booting.txt".
+
 Note that if no color configuration is provided for domains, they fallback to
 the default one, which corresponds simply to all available colors.
 
diff --git a/docs/misc/arm/device-tree/booting.txt 
b/docs/misc/arm/device-tree/booting.txt
index c47a05e0da..3aa493c66d 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -162,6 +162,10 @@ with the following properties:
 
     An integer specifying the number of vcpus to allocate to the guest.
 
+- colors
+    A string specifying the color configuration for the guest. Refer to
+    "docs/misc/arm/cache_coloring.rst" for syntax.
+
 - vpl011
 
     An empty property to enable/disable a virtual pl011 for the guest to
diff --git a/xen/arch/arm/coloring.c b/xen/arch/arm/coloring.c
index cf8aa8a2ca..685a431c3d 100644
--- a/xen/arch/arm/coloring.c
+++ b/xen/arch/arm/coloring.c
@@ -273,8 +273,11 @@ int domain_coloring_init(struct domain *d,
         if ( config->from_guest )
             copy_from_guest(d->arch.colors, config->colors, 
config->num_colors);
         else
+        {
             memcpy(d->arch.colors, config->colors.p,
                    sizeof(unsigned int) * config->num_colors);
+            xfree(config->colors.p);
+        }
     }
 
     if ( !d->arch.colors )
@@ -305,6 +308,20 @@ void domain_dump_coloring_info(struct domain *d)
     print_colors(d->arch.colors, d->arch.num_colors);
 }
 
+void prepare_color_domain_config(struct xen_arch_domainconfig *config,
+                                 const char *colors_str)
+{
+    unsigned int num_colors;
+
+    config->colors.p = xzalloc_array(unsigned int, max_colors);
+    if ( !config->colors.p )
+        panic("Unable to allocate cache colors\n");
+
+    if ( parse_color_config(colors_str, config->colors.p, &num_colors) )
+        panic("Error parsing the color configuration\n");
+    config->num_colors = (uint16_t)num_colors;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 97f2060007..b95e655331 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -25,6 +25,7 @@
 #include <asm/platform.h>
 #include <asm/psci.h>
 #include <asm/setup.h>
+#include <asm/coloring.h>
 #include <asm/cpufeature.h>
 #include <asm/domain_build.h>
 #include <xen/event.h>
@@ -3826,6 +3827,7 @@ void __init create_domUs(void)
     struct dt_device_node *node;
     const struct dt_device_node *cpupool_node,
                                 *chosen = dt_find_node_by_path("/chosen");
+    const char *colors_str;
 
     BUG_ON(chosen == NULL);
     dt_for_each_child_node(chosen, node)
@@ -3914,6 +3916,17 @@ void __init create_domUs(void)
             d_cfg.cpupool_id = pool_id;
         }
 
+        if ( !dt_property_read_string(node, "colors", &colors_str) )
+        {
+            if ( !IS_ENABLED(CONFIG_CACHE_COLORING) )
+                printk(XENLOG_WARNING
+                       "Property 'colors' found, but coloring is disabled\n");
+            else if ( dt_find_property(node, "xen,static-mem", NULL) )
+                panic("static-mem isn't allowed when coloring is enabled\n");
+            else
+                prepare_color_domain_config(&d_cfg.arch, colors_str);
+        }
+
         /*
          * The variable max_init_domid is initialized with zero, so here it's
          * very important to use the pre-increment operator to call
diff --git a/xen/arch/arm/include/asm/coloring.h 
b/xen/arch/arm/include/asm/coloring.h
index a16736819e..549eb408a3 100644
--- a/xen/arch/arm/include/asm/coloring.h
+++ b/xen/arch/arm/include/asm/coloring.h
@@ -38,6 +38,9 @@ int domain_coloring_init(struct domain *d,
 void domain_coloring_free(struct domain *d);
 void domain_dump_coloring_info(struct domain *d);
 
+void prepare_color_domain_config(struct xen_arch_domainconfig *config,
+                                 const char *colors_str);
+
 #else /* !CONFIG_CACHE_COLORING */
 
 static inline bool __init coloring_init(void) { return true; }
@@ -45,6 +48,8 @@ static inline int domain_coloring_init(
     struct domain *d, const struct xen_arch_domainconfig *config) { return 0; }
 static inline void domain_coloring_free(struct domain *d) {}
 static inline void domain_dump_coloring_info(struct domain *d) {}
+static inline void prepare_color_domain_config(
+    struct xen_arch_domainconfig *config, const char *colors_str) {}
 
 #endif /* CONFIG_CACHE_COLORING */
 #endif /* __ASM_ARM_COLORING_H__ */
-- 
2.34.1