[Minios-devel] [UNIKRAFT PATCHv4 32/43] plat/kvm: Parse memory info from device tree for Arm64

[Wei Chen <Wei.Chen@xxxxxxx>]

QEMU/KVM will store the memory informations like memory
region, memory base address and memory size to device
tree. We parse these informations for memory allocater and
new stack setting.

Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
---
 plat/kvm/arm/setup.c | 59 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/plat/kvm/arm/setup.c b/plat/kvm/arm/setup.c
index a881152..685308c 100644
--- a/plat/kvm/arm/setup.c
+++ b/plat/kvm/arm/setup.c
@@ -35,10 +35,15 @@
 #include <uk/plat/console.h>
 #include <uk/assert.h>
 #include <uk/essentials.h>
+#include <arm/cpu_defs.h>
 
 #define MAX_CMDLINE_SIZE 1024
 static char cmdline[MAX_CMDLINE_SIZE];
 
+void *_libkvmplat_pagetable;
+void *_libkvmplat_heap_start;
+void *_libkvmplat_stack_top;
+void *_libkvmplat_mem_end;
 void *_libkvmplat_dtb;
 
 static void _init_dtb(void *dtb_pointer)
@@ -78,6 +83,53 @@ enocmdl:
        strcpy(cmdline, CONFIG_UK_NAME);
 }
 
+static void _init_dtb_mem(void)
+{
+       extern char _text[];
+       extern char _end[];
+       int memory, prop_len = 0;
+       const uint64_t *regs;
+       uint64_t mem_base, mem_size, max_addr;
+
+       /* search for assigned VM memory in DTB */
+       if (fdt_num_mem_rsv(_libkvmplat_dtb) != 0)
+               uk_printd(DLVL_WARN, "Reserved memory is not supported\n");
+
+       memory = fdt_node_offset_by_prop_value(_libkvmplat_dtb, -1,
+                                                  "device_type",
+                                                  "memory", sizeof("memory"));
+       if (memory < 0) {
+               uk_printd(DLVL_WARN, "No memory found in DTB\n");
+               return;
+       }
+
+       /*
+        * QEMU will always provide us at least one bank of memory.
+        * unikraft will use the first bank for the time-being.
+        */
+       regs = fdt_getprop(_libkvmplat_dtb, memory, "reg", &prop_len);
+
+       /*
+        * The property must contain at least the start address
+        * and size, each of which is 8-bytes.
+        */
+       if (regs == NULL && prop_len < 16)
+               UK_CRASH("Bad 'reg' property: %p %d\n", regs, prop_len);
+
+       mem_base = fdt64_to_cpu(regs[0]);
+       mem_size = fdt64_to_cpu(regs[1]);
+       if (mem_base > (uint64_t)&_text)
+               UK_CRASH("Fatal: Image outside of RAM\n");
+
+       max_addr = mem_base + mem_size;
+       _libkvmplat_pagetable =(void *) ALIGN_UP((size_t)&_end, __PAGE_SIZE);
+       _libkvmplat_heap_start = _libkvmplat_pagetable + PAGE_TABLE_SIZE;
+       _libkvmplat_mem_end = (void *) max_addr;
+
+       /* AArch64 require stack be 16-bytes alignment by default */
+       _libkvmplat_stack_top = (void *) ALIGN_UP(max_addr, __STACK_ALIGN_SIZE);
+}
+
 static void _init_cpufeatures(void)
 {
        /* TODO */
@@ -93,4 +145,11 @@ void _libkvmplat_start(void *dtb_pointer)
 
        /* Get command line from DTB */
        _dtb_get_cmdline(cmdline, sizeof(cmdline));
+
+       /* Initialize memory from DTB */
+       _init_dtb_mem();
+
+       uk_printd(DLVL_INFO, "pagetable start: %p\n", _libkvmplat_pagetable);
+       uk_printd(DLVL_INFO, "     heap start: %p\n", _libkvmplat_heap_start);
+       uk_printd(DLVL_INFO, "      stack top: %p\n", _libkvmplat_stack_top);
 }
-- 
2.17.1


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