sev-handle-vc.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3#include "misc.h"
  4#include "error.h"
  5#include "sev.h"
  6
  7#include <linux/kernel.h>
  8#include <linux/string.h>
  9#include <asm/insn.h>
 10#include <asm/pgtable_types.h>
 11#include <asm/ptrace.h>
 12#include <asm/sev.h>
 13#include <asm/trapnr.h>
 14#include <asm/trap_pf.h>
 15#include <asm/fpu/xcr.h>
 16
 17#define __BOOT_COMPRESSED
 18#undef __init
 19#define __init
 20
 21/* Basic instruction decoding support needed */
 22#include "../../lib/inat.c"
 23#include "../../lib/insn.c"
 24
 25/*
 26 * Copy a version of this function here - insn-eval.c can't be used in
 27 * pre-decompression code.
 28 */
 29bool insn_has_rep_prefix(struct insn *insn)
 30{
 31	insn_byte_t p;
 32
 33	insn_get_prefixes(insn);
 34
 35	for_each_insn_prefix(insn, p) {
 36		if (p == 0xf2 || p == 0xf3)
 37			return true;
 38	}
 39
 40	return false;
 41}
 42
 43enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
 44{
 45	char buffer[MAX_INSN_SIZE];
 46	int ret;
 47
 48	memcpy(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE);
 49
 50	ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64);
 51	if (ret < 0)
 52		return ES_DECODE_FAILED;
 53
 54	return ES_OK;
 55}
 56
 57extern void sev_insn_decode_init(void) __alias(inat_init_tables);
 58
 59/*
 60 * Only a dummy for insn_get_seg_base() - Early boot-code is 64bit only and
 61 * doesn't use segments.
 62 */
 63static unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx)
 64{
 65	return 0UL;
 66}
 67
 68static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
 69				   void *dst, char *buf, size_t size)
 70{
 71	memcpy(dst, buf, size);
 72
 73	return ES_OK;
 74}
 75
 76static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 77				  void *src, char *buf, size_t size)
 78{
 79	memcpy(buf, src, size);
 80
 81	return ES_OK;
 82}
 83
 84static enum es_result vc_ioio_check(struct es_em_ctxt *ctxt, u16 port, size_t size)
 85{
 86	return ES_OK;
 87}
 88
 89static bool fault_in_kernel_space(unsigned long address)
 90{
 91	return false;
 92}
 93
 94#define sev_printk(fmt, ...)
 95
 96#include "../../coco/sev/vc-shared.c"
 97
 98void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 99{
100	struct es_em_ctxt ctxt;
101	enum es_result result;
102
103	if (!boot_ghcb && !early_setup_ghcb())
104		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
105
106	vc_ghcb_invalidate(boot_ghcb);
107	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
108	if (result != ES_OK)
109		goto finish;
110
111	result = vc_check_opcode_bytes(&ctxt, exit_code);
112	if (result != ES_OK)
113		goto finish;
114
115	switch (exit_code) {
116	case SVM_EXIT_RDTSC:
117	case SVM_EXIT_RDTSCP:
118		result = vc_handle_rdtsc(boot_ghcb, &ctxt, exit_code);
119		break;
120	case SVM_EXIT_IOIO:
121		result = vc_handle_ioio(boot_ghcb, &ctxt);
122		break;
123	case SVM_EXIT_CPUID:
124		result = vc_handle_cpuid(boot_ghcb, &ctxt);
125		break;
126	default:
127		result = ES_UNSUPPORTED;
128		break;
129	}
130
131finish:
132	if (result == ES_OK)
133		vc_finish_insn(&ctxt);
134	else if (result != ES_RETRY)
135		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
136}