linux/arch/x86/boot/compressed/sev-handle-vc.c

// SPDX-License-Identifier: GPL-2.0

#include "misc.h"
#include "sev.h"

#include <linux/kernel.h>
#include <linux/string.h>
#include <asm/insn.h>
#include <asm/pgtable_types.h>
#include <asm/ptrace.h>
#include <asm/sev.h>
#include <asm/trapnr.h>
#include <asm/trap_pf.h>
#include <asm/fpu/xcr.h>

#define __BOOT_COMPRESSED

/* Basic instruction decoding support needed */
#include "../../lib/inat.c"
#include "../../lib/insn.c"

/*
 * Copy a version of this function here - insn-eval.c can't be used in
 * pre-decompression code.
 */
bool insn_has_rep_prefix(struct insn *insn)
{
	insn_byte_t p;
	int i;

	insn_get_prefixes(insn);

	for_each_insn_prefix(insn, i, p) {
		if (p == 0xf2 || p == 0xf3)
			return true;
	}

	return false;
}

enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
{
	char buffer[MAX_INSN_SIZE];
	int ret;

	memcpy(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE);

	ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64);
	if (ret < 0)
		return ES_DECODE_FAILED;

	return ES_OK;
}

extern void sev_insn_decode_init(void) __alias(inat_init_tables);

/*
 * Only a dummy for insn_get_seg_base() - Early boot-code is 64bit only and
 * doesn't use segments.
 */
static unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx)
{
	return 0UL;
}

static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
				   void *dst, char *buf, size_t size)
{
	memcpy(dst, buf, size);

	return ES_OK;
}

static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
				  void *src, char *buf, size_t size)
{
	memcpy(buf, src, size);

	return ES_OK;
}

static enum es_result vc_ioio_check(struct es_em_ctxt *ctxt, u16 port, size_t size)
{
	return ES_OK;
}

static bool fault_in_kernel_space(unsigned long address)
{
	return false;
}

#define sev_printk(fmt, ...)

#include "../../coco/sev/vc-shared.c"

void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
{
	struct es_em_ctxt ctxt;
	enum es_result result;

	if (!boot_ghcb && !early_setup_ghcb())
		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);

	vc_ghcb_invalidate(boot_ghcb);
	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
	if (result != ES_OK)
		goto finish;

	result = vc_check_opcode_bytes(&ctxt, exit_code);
	if (result != ES_OK)
		goto finish;

	switch (exit_code) {
	case SVM_EXIT_RDTSC:
	case SVM_EXIT_RDTSCP:
		result = vc_handle_rdtsc(boot_ghcb, &ctxt, exit_code);
		break;
	case SVM_EXIT_IOIO:
		result = vc_handle_ioio(boot_ghcb, &ctxt);
		break;
	case SVM_EXIT_CPUID:
		result = vc_handle_cpuid(boot_ghcb, &ctxt);
		break;
	default:
		result = ES_UNSUPPORTED;
		break;
	}

finish:
	if (result == ES_OK)
		vc_finish_insn(&ctxt);
	else if (result != ES_RETRY)
		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
}