[kvm-unit-tests PATCH v2 3/6] x86: efi_main: Get EFI memory map and exit boot services

[Varad Gautam <varadgautam@gmail.com>]

The largest EFI_CONVENTIONAL_MEMORY chunk is passed over to
alloc_phys for the testcase.

Signed-off-by: Varad Gautam <varad.gautam@suse.com>
---
 x86/efi_main.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/x86/efi_main.c b/x86/efi_main.c
index 00e7086..237d4e7 100644
--- a/x86/efi_main.c
+++ b/x86/efi_main.c
@@ -1,11 +1,103 @@
+#include <alloc_phys.h>
 #include <linux/uefi.h>
 
 unsigned long __efiapi efi_main(efi_handle_t handle, efi_system_table_t *sys_tab);
 efi_system_table_t *efi_system_table = NULL;
 
+static void efi_free_pool(void *ptr)
+{
+	efi_bs_call(free_pool, ptr);
+}
+
+static efi_status_t efi_get_memory_map(struct efi_boot_memmap *map)
+{
+	efi_memory_desc_t *m = NULL;
+	efi_status_t status;
+	unsigned long key = 0, map_size = 0, desc_size = 0;
+
+	status = efi_bs_call(get_memory_map, &map_size,
+			     NULL, &key, &desc_size, NULL);
+	if (status != EFI_BUFFER_TOO_SMALL || map_size == 0)
+		goto out;
+
+	/* Pad map_size with additional descriptors so we don't need to
+	 * retry. */
+	map_size += 4 * desc_size;
+	*map->buff_size = map_size;
+	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
+			     map_size, (void **)&m);
+	if (status != EFI_SUCCESS)
+		goto out;
+
+	/* Get the map. */
+	status = efi_bs_call(get_memory_map, &map_size,
+			     m, &key, &desc_size, NULL);
+	if (status != EFI_SUCCESS) {
+		efi_free_pool(m);
+		goto out;
+	}
+
+	*map->desc_size = desc_size;
+	*map->map_size = map_size;
+	*map->key_ptr = key;
+out:
+	*map->map = m;
+	return status;
+}
+
+static efi_status_t efi_exit_boot_services(void *handle,
+					   struct efi_boot_memmap *map)
+{
+	return efi_bs_call(exit_boot_services, handle, *map->key_ptr);
+}
+
+static efi_status_t exit_efi(void *handle)
+{
+	unsigned long map_size = 0, key = 0, desc_size = 0, buff_size;
+	efi_memory_desc_t *mem_map, *md, *conventional = NULL;
+	efi_status_t status;
+	unsigned num_ents, i;
+	unsigned long pages = 0;
+	struct efi_boot_memmap map;
+
+	map.map = &mem_map;
+	map.map_size = &map_size;
+	map.desc_size = &desc_size;
+	map.desc_ver = NULL;
+	map.key_ptr = &key;
+	map.buff_size = &buff_size;
+
+	status = efi_get_memory_map(&map);
+	if (status != EFI_SUCCESS)
+		return status;
+
+	status = efi_exit_boot_services(handle, &map);
+	if (status != EFI_SUCCESS) {
+		efi_free_pool(mem_map);
+		return status;
+	}
+
+	/* Use the largest EFI_CONVENTIONAL_MEMORY range for phys_alloc_init. */
+	num_ents = map_size / desc_size;
+	for (i = 0; i < num_ents; i++) {
+		md = (efi_memory_desc_t *) (((u8 *) mem_map) + i * (desc_size));
+
+		if (md->type == EFI_CONVENTIONAL_MEMORY && md->num_pages > pages) {
+			conventional = md;
+			pages = md->num_pages;
+		}
+	}
+	phys_alloc_init(conventional->phys_addr,
+			conventional->num_pages << EFI_PAGE_SHIFT);
+
+	return EFI_SUCCESS;
+}
+
 unsigned long __efiapi efi_main(efi_handle_t handle, efi_system_table_t *sys_tab)
 {
 	efi_system_table = sys_tab;
 
+	exit_efi(handle);
+
 	return 0;
 }
-- 
2.30.2