HV: added memory allocation functions for AP trampoline code relocation

V2->V3: Fixed the booting issue on MRB board and removed the restriction
        of allocate memory from address 0

1) Fix the booting from MRB issue
-#define    CONFIG_LOW_RAM_SIZE 0x000CF000
+#define    CONFIG_LOW_RAM_SIZE 0x00010000

2) changed e820_alloc_low_memory() to handle corner case of unaligned e820 entries
  and enable it to allocate memory at address 0
+		a length = end > start ? (end - start) : 0;

-       /* We don't want the first page */
-       if ((length == size) && (start == 0))
-           continue;

3) changed emalloc_for_low_mem() to enable to allocate memory at address 0
-       /* We don't want the first page */
-       if (start == 0)
-           start = EFI_PAGE_SIZE;

V1->V2: moved e820_alloc_low_memory() to guest.c and added the logic to
        handle unaligned E820 entries

emalloc_for_low_mem() is used if CONFIG_EFI_STUB is defined.
e820_alloc_low_memory() is used for other cases

In either case, the allocated memory will be marked with E820_TYPE_RESERVED

Signed-off-by: Zheng, Gen <gen.zheng@intel.com>
Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong>
Acked-by: Xu, Anthony <anthony.xu@intel.com>

hypervisor/bsp/sbl/include/bsp/bsp_cfg.h

@@ -41,7 +41,7 @@
 #define HEAP_SIZE	0x100000
 #define CONSOLE_LOGLEVEL_DEFAULT	2
 #define MEM_LOGLEVEL_DEFAULT		4
-#define	CONFIG_LOW_RAM_SIZE	0x000CF000
+#define	CONFIG_LOW_RAM_SIZE	0x00010000
 #define	CONFIG_RAM_START	0x6E000000
 #define	CONFIG_RAM_SIZE		0x02000000	/* 32M */
 #define CONFIG_CMA

hypervisor/bsp/uefi/efi/malloc.c

@@ -164,6 +164,67 @@ fail:
 	return err;
 }
 
+EFI_STATUS emalloc_for_low_mem(EFI_PHYSICAL_ADDRESS *addr, UINTN size)
+{
+	UINTN map_size, map_key, desc_size;
+	EFI_MEMORY_DESCRIPTOR *map_buf;
+	UINTN d, map_end;
+	UINT32 desc_version;
+	EFI_STATUS err;
+	UINTN nr_pages = EFI_SIZE_TO_PAGES(size);
+
+	err = memory_map(&map_buf, &map_size, &map_key,
+			 &desc_size, &desc_version);
+
+   if (err != EFI_SUCCESS)
+		goto fail;
+
+	d = (UINTN)map_buf;
+	map_end = (UINTN)map_buf + map_size;
+
+	for (; d < map_end; d += desc_size) {
+		EFI_MEMORY_DESCRIPTOR *desc;
+		EFI_PHYSICAL_ADDRESS start, end, aligned;
+
+		desc = (EFI_MEMORY_DESCRIPTOR *)d;
+		if (desc->Type != EfiConventionalMemory)
+			continue;
+
+	   if (desc->NumberOfPages < nr_pages)
+			continue;
+
+		start = desc->PhysicalStart;
+		end = start + (desc->NumberOfPages << EFI_PAGE_SHIFT);
+		size = (size + EFI_PAGE_SIZE - 1) & ~(EFI_PAGE_SIZE - 1);
+
+		/* allocate in low memory only */
+		if (start >= 1 << 20)
+			continue;
+
+		if (end > 1 << 20) {
+			size -= end - (1 << 20);
+			end = (1 << 20);
+		}
+
+		if (end - start >= size) {
+			aligned = end - size;
+			err = allocate_pages(AllocateAddress, EfiReservedMemoryType,
+						 nr_pages, &aligned);
+			if (err == EFI_SUCCESS) {
+				*addr = aligned;
+				break;
+			}
+		}
+	}
+
+  if (d == map_end)
+		err = EFI_OUT_OF_RESOURCES;
+
+	free_pool(map_buf);
+fail:
+	return err;
+}
+
 /* FIXME: This function cannot guarantee to return address under 4G,
  * and the hypervisor cannot handle params, which address is above 4G,
  * delivered from efi stub.

hypervisor/bsp/uefi/efi/stdlib.h

@@ -50,6 +50,7 @@ extern void *calloc(UINTN nmemb, UINTN size);
 
 extern EFI_STATUS emalloc(UINTN, UINTN, EFI_PHYSICAL_ADDRESS *);
 extern EFI_STATUS __emalloc(UINTN, UINTN, EFI_PHYSICAL_ADDRESS *, EFI_MEMORY_TYPE);
+extern EFI_STATUS emalloc_for_low_mem(EFI_PHYSICAL_ADDRESS *addr, UINTN size);
 extern void efree(EFI_PHYSICAL_ADDRESS, UINTN);
 
 static inline void memset(void *dstv, char ch, UINTN size)