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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 2/4] 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@xxxxxxx>
Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>
---
Changes from v5 to v6:
- Refine doc.
- Drop duplicated code.
- Add Julien's Reviewed-by.
Changes from v4 to v5:
- Use #address-cells and #size-cells for static heap, do not introduce
new address/size cells. Update the dt-binding accordingly.
- Correct a typo in code comments.
- Drop Stefano's acked-by as it is not valid.
Changes from v3 to v4:
- Change of wording in comments.
- Add the static heap feature in SUPPORT.md as tech preview.
Changes from v2 to v3:
- Define `enum membank_type` properly, drop the typedef.
- Rename the feature terminology to static heap.
- Rename MEMBANK_MEMORY to MEMBANK_DEFAULT and MEMBANK_XEN_DOMAIN to
MEMBANK_STATIC_DOMAIN. Add comments to `enum membank_type`.
- Correct typo, add the clarification of the static heap region
should contain enough memory below 4GB to cater 32-bit DMA for Arm32,
and add the 64KB alignment requirement in doc.
- Add Stefano's Acked-by for device tree interface.
Changes from v1 to v2:
- Rename the device tree property to xen,static-heap to avoid confusion.
- Change of commit msg and doc wording, correct typo in commit msg.
- Do not change the process_chosen_node() return type.
- Add an empty line in make_memory_node() memory type check to improve
readability.
- Use enum membank_type to make the memory type cleaner.
Changes from RFC to v1:
- Rename the terminology to reserved heap.
---
SUPPORT.md | 7 +++++
docs/misc/arm/device-tree/booting.txt | 44 +++++++++++++++++++++++++++
xen/arch/arm/bootfdt.c | 23 +++++++++++---
xen/arch/arm/domain_build.c | 8 +++--
xen/arch/arm/include/asm/setup.h | 22 +++++++++++++-
xen/arch/arm/setup.c | 2 +-
6 files changed, 97 insertions(+), 9 deletions(-)
diff --git a/SUPPORT.md b/SUPPORT.md
index 8e040d1c1e..b02a5d25ca 100644
--- 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 98253414b8..d71f59b63c 100644
--- a/docs/misc/arm/device-tree/booting.txt
+++ b/docs/misc/arm/device-tree/booting.txt
@@ -378,3 +378,47 @@ device-tree:
This will reserve a 512MB region starting at the host physical address
0x30000000 to be exclusively used by DomU1.
+
+
+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.
diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 1a79b969af..0ca7b44446 100644
--- 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 b76a84e8f5..cea82374f7 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1038,9 +1038,11 @@ 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;
@@ -1062,7 +1064,7 @@ 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 5815ccf8c5..09188acae8 100644
--- 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 7814fe323d..3c36c050bf 100644
--- 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);
--
2.17.1
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