[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PULL 11/16] tcg: Really fix cpu_io_recompile
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 11/16] tcg: Really fix cpu_io_recompile |
Date: |
Mon, 26 Mar 2018 15:36:38 +0200 |
From: Richard Henderson <address@hidden>
We have confused the number of instructions that have been
executed in the TB with the number of instructions needed
to repeat the I/O instruction.
We have used cpu_restore_state_from_tb, which means that
the guest pc is pointing to the I/O instruction. The only
time the answer to the later question is not 1 is when
MIPS or SH4 need to re-execute the branch for the delay
slot as well.
We must rely on cpu->cflags_next_tb to generate the next TB,
as otherwise we have a race condition with other guest cpus
within the TB cache.
Fixes: 0790f86861079b1932679d0f011e431aaf4ee9e2
Signed-off-by: Richard Henderson <address@hidden>
Message-Id: <address@hidden>
Tested-by: Pavel Dovgalyuk <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
accel/tcg/translate-all.c | 37 ++++++++++---------------------------
1 file changed, 10 insertions(+), 27 deletions(-)
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 5ad1b91..d419060 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1728,8 +1728,7 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
CPUArchState *env = cpu->env_ptr;
#endif
TranslationBlock *tb;
- uint32_t n, flags;
- target_ulong pc, cs_base;
+ uint32_t n;
tb_lock();
tb = tb_find_pc(retaddr);
@@ -1737,44 +1736,33 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
cpu_abort(cpu, "cpu_io_recompile: could not find TB for pc=%p",
(void *)retaddr);
}
- n = cpu->icount_decr.u16.low + tb->icount;
cpu_restore_state_from_tb(cpu, tb, retaddr);
- /* Calculate how many instructions had been executed before the fault
- occurred. */
- n = n - cpu->icount_decr.u16.low;
- /* Generate a new TB ending on the I/O insn. */
- n++;
+
/* On MIPS and SH, delay slot instructions can only be restarted if
they were already the first instruction in the TB. If this is not
the first instruction in a TB then re-execute the preceding
branch. */
+ n = 1;
#if defined(TARGET_MIPS)
- if ((env->hflags & MIPS_HFLAG_BMASK) != 0 && n > 1) {
+ if ((env->hflags & MIPS_HFLAG_BMASK) != 0
+ && env->active_tc.PC != tb->pc) {
env->active_tc.PC -= (env->hflags & MIPS_HFLAG_B16 ? 2 : 4);
cpu->icount_decr.u16.low++;
env->hflags &= ~MIPS_HFLAG_BMASK;
+ n = 2;
}
#elif defined(TARGET_SH4)
if ((env->flags & ((DELAY_SLOT | DELAY_SLOT_CONDITIONAL))) != 0
- && n > 1) {
+ && env->pc != tb->pc) {
env->pc -= 2;
cpu->icount_decr.u16.low++;
env->flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
+ n = 2;
}
#endif
- /* This should never happen. */
- if (n > CF_COUNT_MASK) {
- cpu_abort(cpu, "TB too big during recompile");
- }
- pc = tb->pc;
- cs_base = tb->cs_base;
- flags = tb->flags;
- tb_phys_invalidate(tb, -1);
-
- /* Execute one IO instruction without caching
- instead of creating large TB. */
- cpu->cflags_next_tb = curr_cflags() | CF_LAST_IO | CF_NOCACHE | 1;
+ /* Generate a new TB executing the I/O insn. */
+ cpu->cflags_next_tb = curr_cflags() | CF_LAST_IO | n;
if (tb->cflags & CF_NOCACHE) {
if (tb->orig_tb) {
@@ -1785,11 +1773,6 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
tb_remove(tb);
}
- /* Generate new TB instead of the current one. */
- /* FIXME: In theory this could raise an exception. In practice
- we have already translated the block once so it's probably ok. */
- tb_gen_code(cpu, pc, cs_base, flags, curr_cflags() | CF_LAST_IO | n);
-
/* TODO: If env->pc != tb->pc (i.e. the faulting instruction was not
* the first in the TB) then we end up generating a whole new TB and
* repeating the fault, which is horribly inefficient.
--
1.8.3.1
- [Qemu-devel] [PULL 03/16] WHPX fix WHvSetPartitionProperty in PropertyCode, (continued)
- [Qemu-devel] [PULL 03/16] WHPX fix WHvSetPartitionProperty in PropertyCode, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 04/16] WHPX improve vcpu_post_run perf, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 05/16] hw/net/can: Fix segfaults when using the devices without bus, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 01/16] scripts/get_maintainer.pl: Print proper error message for missing $file, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 07/16] hw/audio: Fix crashes when devices are used on ISA bus without DMA, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 06/16] fdc: Exit if ISA controller does not support DMA, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 08/16] scripts/device-crash-test: Remove fixed isapc-with-iommu entry, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 09/16] vhost-user-test: do not hang if chardev creation failed, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 11/16] tcg: Really fix cpu_io_recompile,
Paolo Bonzini <=
- [Qemu-devel] [PULL 12/16] chardev-socket: remove useless if, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 13/16] scsi: turn "is this a SCSI device?" into a conditional hint, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 14/16] iothread: fix breakage on windows, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 15/16] chardev/char-fe: Allow NULL chardev in qemu_chr_fe_init(), Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 10/16] vhost-user-test: add back memfd check, Paolo Bonzini, 2018/03/26
- [Qemu-devel] [PULL 16/16] qemu-pr-helper: Actually allow users to specify pidfile, Paolo Bonzini, 2018/03/26
- Re: [Qemu-devel] [PULL 00/16] Misc fixes for QEMU 2.12.0-rc1, Peter Maydell, 2018/03/27