xref: /linux/arch/x86/boot/compressed/mem.c (revision 9e56ff53b4115875667760445b028357848b4748)
1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include "error.h"
4 #include "misc.h"
5 #include "tdx.h"
6 #include "sev.h"
7 #include <asm/shared/tdx.h>
8 
9 /*
10  * accept_memory() and process_unaccepted_memory() called from EFI stub which
11  * runs before decompressor and its early_tdx_detect().
12  *
13  * Enumerate TDX directly from the early users.
14  */
15 static bool early_is_tdx_guest(void)
16 {
17 	static bool once;
18 	static bool is_tdx;
19 
20 	if (!IS_ENABLED(CONFIG_INTEL_TDX_GUEST))
21 		return false;
22 
23 	if (!once) {
24 		u32 eax, sig[3];
25 
26 		cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax,
27 			    &sig[0], &sig[2],  &sig[1]);
28 		is_tdx = !memcmp(TDX_IDENT, sig, sizeof(sig));
29 		once = true;
30 	}
31 
32 	return is_tdx;
33 }
34 
35 void arch_accept_memory(phys_addr_t start, phys_addr_t end)
36 {
37 	/* Platform-specific memory-acceptance call goes here */
38 	if (early_is_tdx_guest()) {
39 		if (!tdx_accept_memory(start, end))
40 			panic("TDX: Failed to accept memory\n");
41 	} else if (sev_snp_enabled()) {
42 		snp_accept_memory(start, end);
43 	} else {
44 		error("Cannot accept memory: unknown platform\n");
45 	}
46 }
47 
48 bool init_unaccepted_memory(void)
49 {
50 	guid_t guid = LINUX_EFI_UNACCEPTED_MEM_TABLE_GUID;
51 	struct efi_unaccepted_memory *table;
52 	unsigned long cfg_table_pa;
53 	unsigned int cfg_table_len;
54 	enum efi_type et;
55 	int ret;
56 
57 	et = efi_get_type(boot_params_ptr);
58 	if (et == EFI_TYPE_NONE)
59 		return false;
60 
61 	ret = efi_get_conf_table(boot_params_ptr, &cfg_table_pa, &cfg_table_len);
62 	if (ret) {
63 		warn("EFI config table not found.");
64 		return false;
65 	}
66 
67 	table = (void *)efi_find_vendor_table(boot_params_ptr, cfg_table_pa,
68 					      cfg_table_len, guid);
69 	if (!table)
70 		return false;
71 
72 	if (table->version != 1)
73 		error("Unknown version of unaccepted memory table\n");
74 
75 	/*
76 	 * In many cases unaccepted_table is already set by EFI stub, but it
77 	 * has to be initialized again to cover cases when the table is not
78 	 * allocated by EFI stub or EFI stub copied the kernel image with
79 	 * efi_relocate_kernel() before the variable is set.
80 	 *
81 	 * It must be initialized before the first usage of accept_memory().
82 	 */
83 	unaccepted_table = table;
84 
85 	return true;
86 }
87