xref: /openbmc/linux/arch/x86/boot/compressed/tdx.c (revision 7f8256ae)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include "../cpuflags.h"
4 #include "../string.h"
5 #include "../io.h"
6 #include "error.h"
7 
8 #include <vdso/limits.h>
9 #include <uapi/asm/vmx.h>
10 
11 #include <asm/shared/tdx.h>
12 
13 /* Called from __tdx_hypercall() for unrecoverable failure */
14 void __tdx_hypercall_failed(void)
15 {
16 	error("TDVMCALL failed. TDX module bug?");
17 }
18 
19 static inline unsigned int tdx_io_in(int size, u16 port)
20 {
21 	struct tdx_hypercall_args args = {
22 		.r10 = TDX_HYPERCALL_STANDARD,
23 		.r11 = EXIT_REASON_IO_INSTRUCTION,
24 		.r12 = size,
25 		.r13 = 0,
26 		.r14 = port,
27 	};
28 
29 	if (__tdx_hypercall_ret(&args))
30 		return UINT_MAX;
31 
32 	return args.r11;
33 }
34 
35 static inline void tdx_io_out(int size, u16 port, u32 value)
36 {
37 	struct tdx_hypercall_args args = {
38 		.r10 = TDX_HYPERCALL_STANDARD,
39 		.r11 = EXIT_REASON_IO_INSTRUCTION,
40 		.r12 = size,
41 		.r13 = 1,
42 		.r14 = port,
43 		.r15 = value,
44 	};
45 
46 	__tdx_hypercall(&args);
47 }
48 
49 static inline u8 tdx_inb(u16 port)
50 {
51 	return tdx_io_in(1, port);
52 }
53 
54 static inline void tdx_outb(u8 value, u16 port)
55 {
56 	tdx_io_out(1, port, value);
57 }
58 
59 static inline void tdx_outw(u16 value, u16 port)
60 {
61 	tdx_io_out(2, port, value);
62 }
63 
64 void early_tdx_detect(void)
65 {
66 	u32 eax, sig[3];
67 
68 	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);
69 
70 	if (memcmp(TDX_IDENT, sig, sizeof(sig)))
71 		return;
72 
73 	/* Use hypercalls instead of I/O instructions */
74 	pio_ops.f_inb  = tdx_inb;
75 	pio_ops.f_outb = tdx_outb;
76 	pio_ops.f_outw = tdx_outw;
77 }
78