docs, xen/arm: Introduce static heap memory

This commit introduces the static heap memory, which is parts of RAM
reserved in the beginning of the boot time for heap.

Firstly, since a new type of memory bank is needed for marking the
memory bank solely as the heap, this commit defines `enum membank_type`
and use this enum in function device_tree_get_meminfo(). Changes of
code are done accordingly following the introduction of this enum.

Also, this commit introduces the logic to parse the static heap
configuration in device tree. If the memory bank is reserved as heap
through `xen,static-heap` property in device tree `chosen` node, the
memory will be marked as static heap type.

A documentation section is added, describing the definition of static
heap memory and the method of enabling the static heap memory through
device tree at boot time.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>

diff --git a/SUPPORT.md b/SUPPORT.md
index 8e040d1c1ef50cfe06f851d5dd0abe1910ec0cbc..b02a5d25ca31a8601e8f0b79883a29eeed32720d 100644 (file)
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -293,6 +293,13 @@ pre-defined by configuration using physical address ranges.
 
     Status, ARM: Tech Preview
 
+### Static Heap
+
+Allow reserving parts of RAM through the device tree using physical
+address ranges as heap.
+
+    Status, ARM: Tech Preview
+
 ### Memory Sharing
 
 Allow sharing of identical pages between guests

diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt
index e03e5e9e4cc29ac43b2daf74b526bc5d01e798d3..5395a1077c1f728ba189e1833abeef89fd51d4d3 100644 (file)
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -425,6 +425,49 @@ The static event channel node has the following properties:
     link-to-foreign-evtchn is a single phandle to a remote evtchn to which
     local-evtchn will be connected.
 
+Static Heap Memory
+==================
+
+The static heap memory refers to parts of RAM reserved in the beginning of
+boot time for heap. The memory is reserved by configuration in the device
+tree using physical address ranges.
+
+The static heap memory declared in the device tree defines the memory areas
+that will be reserved to be used exclusively as heap.
+
+- For Arm32, since there are separated heaps, the static heap will be used
+for both domheap and xenheap. The admin should make sure that the static
+heap region should contain enough memory below 4GB to cater 32-bit DMA.
+
+- For Arm64, since there is a single heap, the defined static heap areas
+shall always go to the heap allocator.
+
+The static heap memory is an optional feature and can be enabled by adding
+below device tree property.
+
+- xen,static-heap
+
+    Property under the top-level "chosen" node. It specifies the address
+    and size of Xen static heap memory. Number of address and size cells
+    for the "xen,static-heap" property is determined by the root node
+    "#address-cells" and "#size-cells". Note that at least a 64KB alignment
+    is required.
+
+Below is an example on how to specify the static heap in device tree:
+
+    / {
+        #address-cells = <0x2>;
+        #size-cells = <0x2>;
+        ...
+        chosen {
+            xen,static-heap = <0x0 0x30000000 0x0 0x40000000>;
+            ...
+        };
+    };
+
+RAM starting from the host physical address 0x30000000 of 1GB size will
+be reserved as static heap.
+
 Example
 =======
 

diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 1a79b969af4f43329a94e0cdedd2d4f0cd06fcaa..0ca7b4444642e5bdc9e32f6ffee21d20e01ed0c3 100644 (file)
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -64,7 +64,7 @@ void __init device_tree_get_reg(const __be32 **cell, u32 address_cells,
 static int __init device_tree_get_meminfo(const void *fdt, int node,
                                           const char *prop_name,
                                           u32 address_cells, u32 size_cells,
-                                          void *data, bool xen_domain)
+                                          void *data, enum membank_type type)
 {
     const struct fdt_property *prop;
     unsigned int i, banks;
@@ -95,7 +95,7 @@ static int __init device_tree_get_meminfo(const void *fdt, int node,
             continue;
         mem->bank[mem->nr_banks].start = start;
         mem->bank[mem->nr_banks].size = size;
-        mem->bank[mem->nr_banks].xen_domain = xen_domain;
+        mem->bank[mem->nr_banks].type = type;
         mem->nr_banks++;
     }
 
@@ -185,7 +185,7 @@ static int __init process_memory_node(const void *fdt, int node,
                                       void *data)
 {
     return device_tree_get_meminfo(fdt, node, "reg", address_cells, size_cells,
-                                   data, false);
+                                   data, MEMBANK_DEFAULT);
 }
 
 static int __init process_reserved_memory_node(const void *fdt, int node,
@@ -301,6 +301,20 @@ static int __init process_chosen_node(const void *fdt, int node,
     paddr_t start, end;
     int len;
 
+    if ( fdt_get_property(fdt, node, "xen,static-heap", NULL) )
+    {
+        int rc;
+
+        printk("Checking for static heap in /chosen\n");
+
+        rc = device_tree_get_meminfo(fdt, node, "xen,static-heap",
+                                     address_cells, size_cells,
+                                     &bootinfo.reserved_mem,
+                                     MEMBANK_STATIC_HEAP);
+        if ( rc )
+            return rc;
+    }
+
     printk("Checking for initrd in /chosen\n");
 
     prop = fdt_get_property(fdt, node, "linux,initrd-start", &len);
@@ -360,7 +374,8 @@ static int __init process_domain_node(const void *fdt, int node,
                                      "#xen,static-mem-size-cells", 0);
 
     return device_tree_get_meminfo(fdt, node, "xen,static-mem", address_cells,
-                                   size_cells, &bootinfo.reserved_mem, true);
+                                   size_cells, &bootinfo.reserved_mem,
+                                   MEMBANK_STATIC_DOMAIN);
 }
 
 static int __init early_scan_node(const void *fdt,

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 1d6b414c73a7efe7ccf28b1bda63297054ed184c..7412303d2058a4b33d672c22ec5683d0b5102870 100644 (file)
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1040,9 +1040,11 @@ static int __init make_memory_node(const struct domain *d,
     if ( mem->nr_banks == 0 )
         return -ENOENT;
 
-    /* find first memory range not bound to a Xen domain */
-    for ( i = 0; i < mem->nr_banks && mem->bank[i].xen_domain; i++ )
+    /* find the first memory range that is reserved for device (or firmware) */
+    for ( i = 0; i < mem->nr_banks &&
+                 (mem->bank[i].type != MEMBANK_DEFAULT); i++ )
         ;
+
     if ( i == mem->nr_banks )
         return 0;
 
@@ -1064,7 +1066,7 @@ static int __init make_memory_node(const struct domain *d,
         u64 start = mem->bank[i].start;
         u64 size = mem->bank[i].size;
 
-        if ( mem->bank[i].xen_domain )
+        if ( mem->bank[i].type == MEMBANK_STATIC_DOMAIN )
             continue;
 
         dt_dprintk("  Bank %d: %#"PRIx64"->%#"PRIx64"\n",

diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
index 5ee28b270fad6272afa721b20b10de1dfb9ba644..94b7e74b4d2ffd9b3bf171a46f904c3626f2df03 100644 (file)
--- a/xen/arch/arm/include/asm/setup.h
+++ b/xen/arch/arm/include/asm/setup.h
@@ -22,11 +22,31 @@ typedef enum {
     BOOTMOD_UNKNOWN
 }  bootmodule_kind;
 
+enum membank_type {
+    /*
+     * The MEMBANK_DEFAULT type refers to either reserved memory for the
+     * device/firmware (when the bank is in 'reserved_mem') or any RAM (when
+     * the bank is in 'mem').
+     */
+    MEMBANK_DEFAULT,
+    /*
+     * The MEMBANK_STATIC_DOMAIN type is used to indicate whether the memory
+     * bank is bound to a static Xen domain. It is only valid when the bank
+     * is in reserved_mem.
+     */
+    MEMBANK_STATIC_DOMAIN,
+    /*
+     * The MEMBANK_STATIC_HEAP type is used to indicate whether the memory
+     * bank is reserved as static heap. It is only valid when the bank is
+     * in reserved_mem.
+     */
+    MEMBANK_STATIC_HEAP,
+};
 
 struct membank {
     paddr_t start;
     paddr_t size;
-    bool xen_domain; /* whether the memory bank is bound to a Xen domain. */
+    enum membank_type type;
 };
 
 struct meminfo {

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 909013992e3689d5cb7513f5f4f28f0ee332fbc7..5b7602fdac716688c3823c061c514d2e35ffdd54 100644 (file)
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -644,7 +644,7 @@ static void __init init_staticmem_pages(void)
 
     for ( bank = 0 ; bank < bootinfo.reserved_mem.nr_banks; bank++ )
     {
-        if ( bootinfo.reserved_mem.bank[bank].xen_domain )
+        if ( bootinfo.reserved_mem.bank[bank].type == MEMBANK_STATIC_DOMAIN )
         {
             mfn_t bank_start = _mfn(PFN_UP(bootinfo.reserved_mem.bank[bank].start));
             unsigned long bank_pages = PFN_DOWN(bootinfo.reserved_mem.bank[bank].size);