[Qemu-devel] [PATCH for-4.1 24/24] icount: clean up cpu_can_io before jumping to the next block

Pavel Dovgalyuk posted 24 patches 6 years, 6 months ago
Maintainers: Josh Durgin <jdurgin@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Peter Lieven <pl@kamp.de>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Ronnie Sahlberg <ronniesahlberg@gmail.com>, Markus Armbruster <armbru@redhat.com>, Richard Henderson <rth@twiddle.net>, Michael Roth <mdroth@linux.vnet.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Thomas Huth <thuth@redhat.com>, Max Reitz <mreitz@redhat.com>, Laurent Vivier <lvivier@redhat.com>, Fam Zheng <fam@euphon.net>, Juan Quintela <quintela@redhat.com>, Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>, Eric Blake <eblake@redhat.com>
[Qemu-devel] [PATCH for-4.1 24/24] icount: clean up cpu_can_io before jumping to the next block
Posted by Pavel Dovgalyuk 6 years, 6 months ago
From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

Most of IO instructions can be executed only at the end of the block in
icount mode. Therefore translator can set cpu_can_io flag when translating
the last instruction.
But when the blocks are chained, then this flag is not reset and may
remain set at the beginning of the next block.
This patch resets the flag before "chaining" the translation blocks.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
---
 accel/tcg/tcg-runtime.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/accel/tcg/tcg-runtime.c b/accel/tcg/tcg-runtime.c
index d0d4484406..5871f5aba2 100644
--- a/accel/tcg/tcg-runtime.c
+++ b/accel/tcg/tcg-runtime.c
@@ -151,6 +151,8 @@ void *HELPER(lookup_tb_ptr)(CPUArchState *env)
     target_ulong cs_base, pc;
     uint32_t flags;
 
+    /* We are going to jump to the next block. can_do_io should be reset */
+    cpu->can_do_io = !use_icount;
     tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, curr_cflags());
     if (tb == NULL) {
         return tcg_ctx->code_gen_epilogue;