qemu/target/i386/tcg/excp_helper.c
Paolo Bonzini 958e1dd130 target/i386: Raise #GP on unaligned m128 accesses when required.
Many instructions which load/store 128-bit values are supposed to
raise #GP when the memory operand isn't 16-byte aligned. This includes:
 - Instructions explicitly requiring memory alignment (Exceptions Type 1
   in the "AVX and SSE Instruction Exception Specification" section of
   the SDM)
 - Legacy SSE instructions that load/store 128-bit values (Exceptions
   Types 2 and 4).

This change sets MO_ALIGN_16 on 128-bit memory accesses that require
16-byte alignment. It adds cpu_record_sigbus and cpu_do_unaligned_access
hooks that simulate a #GP exception in qemu-user and qemu-system,
respectively.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/217
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Ricky Zhou <ricky@rzhou.org>
Message-Id: <20220830034816.57091-2-ricky@rzhou.org>
[Do not bother checking PREFIX_VEX, since AVX is not supported. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-18 09:17:40 +02:00

156 lines
5.1 KiB
C

/*
* x86 exception helpers
*
* Copyright (c) 2003 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "qemu/log.h"
#include "sysemu/runstate.h"
#include "exec/helper-proto.h"
#include "helper-tcg.h"
G_NORETURN void helper_raise_interrupt(CPUX86State *env, int intno,
int next_eip_addend)
{
raise_interrupt(env, intno, 1, 0, next_eip_addend);
}
G_NORETURN void helper_raise_exception(CPUX86State *env, int exception_index)
{
raise_exception(env, exception_index);
}
/*
* Check nested exceptions and change to double or triple fault if
* needed. It should only be called, if this is not an interrupt.
* Returns the new exception number.
*/
static int check_exception(CPUX86State *env, int intno, int *error_code,
uintptr_t retaddr)
{
int first_contributory = env->old_exception == 0 ||
(env->old_exception >= 10 &&
env->old_exception <= 13);
int second_contributory = intno == 0 ||
(intno >= 10 && intno <= 13);
qemu_log_mask(CPU_LOG_INT, "check_exception old: 0x%x new 0x%x\n",
env->old_exception, intno);
#if !defined(CONFIG_USER_ONLY)
if (env->old_exception == EXCP08_DBLE) {
if (env->hflags & HF_GUEST_MASK) {
cpu_vmexit(env, SVM_EXIT_SHUTDOWN, 0, retaddr); /* does not return */
}
qemu_log_mask(CPU_LOG_RESET, "Triple fault\n");
qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
return EXCP_HLT;
}
#endif
if ((first_contributory && second_contributory)
|| (env->old_exception == EXCP0E_PAGE &&
(second_contributory || (intno == EXCP0E_PAGE)))) {
intno = EXCP08_DBLE;
*error_code = 0;
}
if (second_contributory || (intno == EXCP0E_PAGE) ||
(intno == EXCP08_DBLE)) {
env->old_exception = intno;
}
return intno;
}
/*
* Signal an interruption. It is executed in the main CPU loop.
* is_int is TRUE if coming from the int instruction. next_eip is the
* env->eip value AFTER the interrupt instruction. It is only relevant if
* is_int is TRUE.
*/
static G_NORETURN
void raise_interrupt2(CPUX86State *env, int intno,
int is_int, int error_code,
int next_eip_addend,
uintptr_t retaddr)
{
CPUState *cs = env_cpu(env);
if (!is_int) {
cpu_svm_check_intercept_param(env, SVM_EXIT_EXCP_BASE + intno,
error_code, retaddr);
intno = check_exception(env, intno, &error_code, retaddr);
} else {
cpu_svm_check_intercept_param(env, SVM_EXIT_SWINT, 0, retaddr);
}
cs->exception_index = intno;
env->error_code = error_code;
env->exception_is_int = is_int;
env->exception_next_eip = env->eip + next_eip_addend;
cpu_loop_exit_restore(cs, retaddr);
}
/* shortcuts to generate exceptions */
G_NORETURN void raise_interrupt(CPUX86State *env, int intno, int is_int,
int error_code, int next_eip_addend)
{
raise_interrupt2(env, intno, is_int, error_code, next_eip_addend, 0);
}
G_NORETURN void raise_exception_err(CPUX86State *env, int exception_index,
int error_code)
{
raise_interrupt2(env, exception_index, 0, error_code, 0, 0);
}
G_NORETURN void raise_exception_err_ra(CPUX86State *env, int exception_index,
int error_code, uintptr_t retaddr)
{
raise_interrupt2(env, exception_index, 0, error_code, 0, retaddr);
}
G_NORETURN void raise_exception(CPUX86State *env, int exception_index)
{
raise_interrupt2(env, exception_index, 0, 0, 0, 0);
}
G_NORETURN void raise_exception_ra(CPUX86State *env, int exception_index,
uintptr_t retaddr)
{
raise_interrupt2(env, exception_index, 0, 0, 0, retaddr);
}
G_NORETURN void handle_unaligned_access(CPUX86State *env, vaddr vaddr,
MMUAccessType access_type,
uintptr_t retaddr)
{
/*
* Unaligned accesses are currently only triggered by SSE/AVX
* instructions that impose alignment requirements on memory
* operands. These instructions raise #GP(0) upon accessing an
* unaligned address.
*/
raise_exception_ra(env, EXCP0D_GPF, retaddr);
}