[PATCH 01/10] xen/arm: introduce domain on Static Allocation

[Penny Zheng <penny.zheng@xxxxxxx>]

Static Allocation refers to system or sub-system(domains) for which memory
areas are pre-defined by configuration using physical address ranges.
Those pre-defined memory, -- Static Momery, as parts of RAM reserved in the
beginning, shall never go to heap allocator or boot allocator for any use.

Domains on Static Allocation is supported through device tree property
`xen,static-mem` specifying reserved RAM banks as this domain's guest RAM.
By default, they shall be mapped to the fixed guest RAM address
`GUEST_RAM0_BASE`, `GUEST_RAM1_BASE`.

This patch introduces this new `xen,static-mem` property to define static
memory nodes in device tree file.
This patch also documents and parses this new attribute at boot time and
stores related info in static_mem for later initialization.

Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
---
 docs/misc/arm/device-tree/booting.txt | 33 +++++++++++++++++
 xen/arch/arm/bootfdt.c                | 52 +++++++++++++++++++++++++++
 xen/include/asm-arm/setup.h           |  2 ++
 3 files changed, 87 insertions(+)

diff --git a/docs/misc/arm/device-tree/booting.txt 
b/docs/misc/arm/device-tree/booting.txt
index 5243bc7fd3..d209149d71 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -268,3 +268,36 @@ The DTB fragment is loaded at 0xc000000 in the example 
above. It should
 follow the convention explained in docs/misc/arm/passthrough.txt. The
 DTB fragment will be added to the guest device tree, so that the guest
 kernel will be able to discover the device.
+
+
+Static Allocation
+=============
+
+Static Allocation refers to system or sub-system(domains) for which memory
+areas are pre-defined by configuration using physical address ranges.
+Those pre-defined memory, -- Static Momery, as parts of RAM reserved in the
+beginning, shall never go to heap allocator or boot allocator for any use.
+
+Domains on Static Allocation is supported through device tree property
+`xen,static-mem` specifying reserved RAM banks as this domain's guest RAM.
+By default, they shall be mapped to the fixed guest RAM address
+`GUEST_RAM0_BASE`, `GUEST_RAM1_BASE`.
+
+Static Allocation is only supported on AArch64 for now.
+
+The dtb property should look like as follows:
+
+        chosen {
+            domU1 {
+                compatible = "xen,domain";
+                #address-cells = <0x2>;
+                #size-cells = <0x2>;
+                cpus = <2>;
+                xen,static-mem = <0x0 0x30000000 0x0 0x20000000>;
+
+                ...
+            };
+        };
+
+DOMU1 on Static Allocation has reserved RAM bank at 0x30000000 of 512MB size
+as guest RAM.
diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index dcff512648..e9f14e6a44 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -327,6 +327,55 @@ static void __init process_chosen_node(const void *fdt, 
int node,
     add_boot_module(BOOTMOD_RAMDISK, start, end-start, false);
 }
 
+static int __init process_static_memory(const void *fdt, int node,
+                                        const char *name,
+                                        u32 address_cells, u32 size_cells,
+                                        void *data)
+{
+    int i;
+    int banks;
+    const __be32 *cell;
+    paddr_t start, size;
+    u32 reg_cells = address_cells + size_cells;
+    struct meminfo *mem = data;
+    const struct fdt_property *prop;
+
+    if ( address_cells < 1 || size_cells < 1 )
+    {
+        printk("fdt: invalid #address-cells or #size-cells for static memory");
+        return -EINVAL;
+    }
+
+    /*
+     * Check if static memory property belongs to a specific domain, that is,
+     * its node `domUx` has compatible string "xen,domain".
+     */
+    if ( fdt_node_check_compatible(fdt, node, "xen,domain") != 0 )
+        printk("xen,static-mem property can only locate under /domUx node.\n");
+
+    prop = fdt_get_property(fdt, node, name, NULL);
+    if ( !prop )
+        return -ENOENT;
+
+    cell = (const __be32 *)prop->data;
+    banks = fdt32_to_cpu(prop->len) / (reg_cells * sizeof (u32));
+
+    for ( i = 0; i < banks && mem->nr_banks < NR_MEM_BANKS; i++ )
+    {
+        device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
+        /* Some DT may describe empty bank, ignore them */
+        if ( !size )
+            continue;
+        mem->bank[mem->nr_banks].start = start;
+        mem->bank[mem->nr_banks].size = size;
+        mem->nr_banks++;
+    }
+
+    if ( i < banks )
+        return -ENOSPC;
+    return 0;
+}
+
 static int __init early_scan_node(const void *fdt,
                                   int node, const char *name, int depth,
                                   u32 address_cells, u32 size_cells,
@@ -345,6 +394,9 @@ static int __init early_scan_node(const void *fdt,
         process_multiboot_node(fdt, node, name, address_cells, size_cells);
     else if ( depth == 1 && device_tree_node_matches(fdt, node, "chosen") )
         process_chosen_node(fdt, node, name, address_cells, size_cells);
+    else if ( depth == 2 && fdt_get_property(fdt, node, "xen,static-mem", 
NULL) )
+        process_static_memory(fdt, node, "xen,static-mem", address_cells,
+                              size_cells, &bootinfo.static_mem);
 
     if ( rc < 0 )
         printk("fdt: node `%s': parsing failed\n", name);
diff --git a/xen/include/asm-arm/setup.h b/xen/include/asm-arm/setup.h
index 5283244015..5e9f296760 100644
--- a/xen/include/asm-arm/setup.h
+++ b/xen/include/asm-arm/setup.h
@@ -74,6 +74,8 @@ struct bootinfo {
 #ifdef CONFIG_ACPI
     struct meminfo acpi;
 #endif
+    /* Static Memory */
+    struct meminfo static_mem;
 };
 
 extern struct bootinfo bootinfo;
-- 
2.25.1