Commit c494eb36 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Dave Hansen
Browse files

x86/sev-es: Use insn_decode_mmio() for MMIO implementation 



Switch SEV implementation to insn_decode_mmio(). The helper is going
to be used by TDX too.

No functional changes.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Tested-by: default avatarJoerg Roedel <jroedel@suse.de>
Acked-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20211130184933.31005-5-kirill.shutemov@linux.intel.com
parent 70a81f99

arch/x86/kernel/sev.c

+41 −131
Original line number Diff line number Diff line
@@ -776,22 +776,6 @@ static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt) 
	do_early_exception(ctxt->regs, trapnr);

}



static long *vc_insn_get_reg(struct es_em_ctxt *ctxt)

{

	long *reg_array;

	int offset;



	reg_array = (long *)ctxt->regs;

	offset    = insn_get_modrm_reg_off(&ctxt->insn, ctxt->regs);



	if (offset < 0)

		return NULL;



	offset /= sizeof(long);



	return reg_array + offset;

}



static long *vc_insn_get_rm(struct es_em_ctxt *ctxt)

{

	long *reg_array;
@@ -839,76 +823,6 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt, 
	return sev_es_ghcb_hv_call(ghcb, true, ctxt, exit_code, exit_info_1, exit_info_2);

}



static enum es_result vc_handle_mmio_twobyte_ops(struct ghcb *ghcb,

						 struct es_em_ctxt *ctxt)

{

	struct insn *insn = &ctxt->insn;

	unsigned int bytes = 0;

	enum es_result ret;

	int sign_byte;

	long *reg_data;



	switch (insn->opcode.bytes[1]) {

		/* MMIO Read w/ zero-extension */

	case 0xb6:

		bytes = 1;

		fallthrough;

	case 0xb7:

		if (!bytes)

			bytes = 2;



		ret = vc_do_mmio(ghcb, ctxt, bytes, true);

		if (ret)

			break;



		/* Zero extend based on operand size */

		reg_data = vc_insn_get_reg(ctxt);

		if (!reg_data)

			return ES_DECODE_FAILED;



		memset(reg_data, 0, insn->opnd_bytes);



		memcpy(reg_data, ghcb->shared_buffer, bytes);

		break;



		/* MMIO Read w/ sign-extension */

	case 0xbe:

		bytes = 1;

		fallthrough;

	case 0xbf:

		if (!bytes)

			bytes = 2;



		ret = vc_do_mmio(ghcb, ctxt, bytes, true);

		if (ret)

			break;



		/* Sign extend based on operand size */

		reg_data = vc_insn_get_reg(ctxt);

		if (!reg_data)

			return ES_DECODE_FAILED;



		if (bytes == 1) {

			u8 *val = (u8 *)ghcb->shared_buffer;



			sign_byte = (*val & 0x80) ? 0xff : 0x00;

		} else {

			u16 *val = (u16 *)ghcb->shared_buffer;



			sign_byte = (*val & 0x8000) ? 0xff : 0x00;

		}

		memset(reg_data, sign_byte, insn->opnd_bytes);



		memcpy(reg_data, ghcb->shared_buffer, bytes);

		break;



	default:

		ret = ES_UNSUPPORTED;

	}



	return ret;

}



/*

 * The MOVS instruction has two memory operands, which raises the

 * problem that it is not known whether the access to the source or the
@@ -976,83 +890,79 @@ static enum es_result vc_handle_mmio_movs(struct es_em_ctxt *ctxt, 
		return ES_RETRY;

}



static enum es_result vc_handle_mmio(struct ghcb *ghcb,

				     struct es_em_ctxt *ctxt)

static enum es_result vc_handle_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt)

{

	struct insn *insn = &ctxt->insn;

	unsigned int bytes = 0;

	enum mmio_type mmio;

	enum es_result ret;

	u8 sign_byte;

	long *reg_data;



	switch (insn->opcode.bytes[0]) {

	/* MMIO Write */

	case 0x88:

		bytes = 1;

		fallthrough;

	case 0x89:

		if (!bytes)

			bytes = insn->opnd_bytes;

	mmio = insn_decode_mmio(insn, &bytes);

	if (mmio == MMIO_DECODE_FAILED)

		return ES_DECODE_FAILED;



		reg_data = vc_insn_get_reg(ctxt);

	if (mmio != MMIO_WRITE_IMM && mmio != MMIO_MOVS) {

		reg_data = insn_get_modrm_reg_ptr(insn, ctxt->regs);

		if (!reg_data)

			return ES_DECODE_FAILED;

	}



	switch (mmio) {

	case MMIO_WRITE:

		memcpy(ghcb->shared_buffer, reg_data, bytes);



		ret = vc_do_mmio(ghcb, ctxt, bytes, false);

		break;



	case 0xc6:

		bytes = 1;

		fallthrough;

	case 0xc7:

		if (!bytes)

			bytes = insn->opnd_bytes;



	case MMIO_WRITE_IMM:

		memcpy(ghcb->shared_buffer, insn->immediate1.bytes, bytes);



		ret = vc_do_mmio(ghcb, ctxt, bytes, false);

		break;



		/* MMIO Read */

	case 0x8a:

		bytes = 1;

		fallthrough;

	case 0x8b:

		if (!bytes)

			bytes = insn->opnd_bytes;



	case MMIO_READ:

		ret = vc_do_mmio(ghcb, ctxt, bytes, true);

		if (ret)

			break;



		reg_data = vc_insn_get_reg(ctxt);

		if (!reg_data)

			return ES_DECODE_FAILED;



		/* Zero-extend for 32-bit operation */

		if (bytes == 4)

			*reg_data = 0;



		memcpy(reg_data, ghcb->shared_buffer, bytes);

		break;

	case MMIO_READ_ZERO_EXTEND:

		ret = vc_do_mmio(ghcb, ctxt, bytes, true);

		if (ret)

			break;



		/* MOVS instruction */

	case 0xa4:

		bytes = 1;

		fallthrough;

	case 0xa5:

		if (!bytes)

			bytes = insn->opnd_bytes;

		/* Zero extend based on operand size */

		memset(reg_data, 0, insn->opnd_bytes);

		memcpy(reg_data, ghcb->shared_buffer, bytes);

		break;

	case MMIO_READ_SIGN_EXTEND:

		ret = vc_do_mmio(ghcb, ctxt, bytes, true);

		if (ret)

			break;



		ret = vc_handle_mmio_movs(ctxt, bytes);

		if (bytes == 1) {

			u8 *val = (u8 *)ghcb->shared_buffer;



			sign_byte = (*val & 0x80) ? 0xff : 0x00;

		} else {

			u16 *val = (u16 *)ghcb->shared_buffer;



			sign_byte = (*val & 0x8000) ? 0xff : 0x00;

		}



		/* Sign extend based on operand size */

		memset(reg_data, sign_byte, insn->opnd_bytes);

		memcpy(reg_data, ghcb->shared_buffer, bytes);

		break;

		/* Two-Byte Opcodes */

	case 0x0f:

		ret = vc_handle_mmio_twobyte_ops(ghcb, ctxt);

	case MMIO_MOVS:

		ret = vc_handle_mmio_movs(ctxt, bytes);

		break;

	default:

		ret = ES_UNSUPPORTED;

		break;

	}



	return ret;