[Spice-commits] 2 commits - exec-all.h qemu-img.c qemu-io.c tcg/ppc
Gerd Hoffmann
kraxel at kemper.freedesktop.org
Thu Nov 8 10:59:06 PST 2012
exec-all.h | 2 +-
qemu-img.c | 3 +--
qemu-io.c | 3 +--
tcg/ppc/tcg-target.c | 32 ++++++++++++++++++++++++--------
4 files changed, 27 insertions(+), 13 deletions(-)
New commits:
commit 2592c59a66d456fe98fe96cb5787b356c40ee66f
Author: Paolo Bonzini <pbonzini at redhat.com>
Date: Sat Nov 3 18:10:17 2012 +0100
tools: initialize main loop before block layer
Tools were broken because they initialized the block layer while
qemu_aio_context was still NULL.
Reported-by: malc <av1474 at comtv.ru>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Signed-off-by: malc <av1474 at comtv.ru>
diff --git a/qemu-img.c b/qemu-img.c
index b17bddd..e29e01b 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2001,14 +2001,13 @@ int main(int argc, char **argv)
error_set_progname(argv[0]);
+ qemu_init_main_loop();
bdrv_init();
if (argc < 2)
help();
cmdname = argv[1];
argc--; argv++;
- qemu_init_main_loop();
-
/* find the command */
for(cmd = img_cmds; cmd->name != NULL; cmd++) {
if (!strcmp(cmdname, cmd->name)) {
diff --git a/qemu-io.c b/qemu-io.c
index d0f4fb7..1ad7d3a 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -1892,9 +1892,8 @@ int main(int argc, char **argv)
exit(1);
}
- bdrv_init();
-
qemu_init_main_loop();
+ bdrv_init();
/* initialize commands */
quit_init();
commit c878da3b27ceeed953c9f9a1eb002d59e9dcb4c6
Author: malc <av1474 at comtv.ru>
Date: Mon Nov 5 21:47:04 2012 +0400
tcg/ppc32: Use trampolines to trim the code size for mmu slow path accessors
mmu access looks something like:
<check tlb>
if miss goto slow_path
<fast path>
done:
...
; end of the TB
slow_path:
<pre process>
mr r3, r27 ; move areg0 to r3
; (r3 holds the first argument for all the PPC32 ABIs)
<call mmu_helper>
b $+8
.long done
<post process>
b done
On ppc32 <call mmu_helper> is:
(SysV and Darwin)
mmu_helper is most likely not within direct branching distance from
the call site, necessitating
a. moving 32 bit offset of mmu_helper into a GPR ; 8 bytes
b. moving GPR to CTR/LR ; 4 bytes
c. (finally) branching to CTR/LR ; 4 bytes
r3 setting - 4 bytes
call - 16 bytes
dummy jump over retaddr - 4 bytes
embedded retaddr - 4 bytes
Total overhead - 28 bytes
(PowerOpen (AIX))
a. moving 32 bit offset of mmu_helper's TOC into a GPR1 ; 8 bytes
b. loading 32 bit function pointer into GPR2 ; 4 bytes
c. moving GPR2 to CTR/LR ; 4 bytes
d. loading 32 bit small area pointer into R2 ; 4 bytes
e. (finally) branching to CTR/LR ; 4 bytes
r3 setting - 4 bytes
call - 24 bytes
dummy jump over retaddr - 4 bytes
embedded retaddr - 4 bytes
Total overhead - 36 bytes
Following is done to trim the code size of slow path sections:
In tcg_target_qemu_prologue trampolines are emitted that look like this:
trampoline:
mfspr r3, LR
addi r3, 4
mtspr LR, r3 ; fixup LR to point over embedded retaddr
mr r3, r27
<jump mmu_helper> ; tail call of sorts
And slow path becomes:
slow_path:
<pre process>
<call trampoline>
.long done
<post process>
b done
call - 4 bytes (trampoline is within code gen buffer
and most likely accessible via
direct branch)
embedded retaddr - 4 bytes
Total overhead - 8 bytes
In the end the icache pressure is decreased by 20/28 bytes at the cost
of an extra jump to trampoline and adjusting LR (to skip over embedded
retaddr) once inside.
Signed-off-by: malc <av1474 at comtv.ru>
diff --git a/exec-all.h b/exec-all.h
index 94ed613..6b3272a 100644
--- a/exec-all.h
+++ b/exec-all.h
@@ -337,7 +337,7 @@ extern uintptr_t tci_tb_ptr;
*(int32_t *)((void *)GETRA() + 3) - 1))
# elif defined (_ARCH_PPC) && !defined (_ARCH_PPC64)
# define GETRA() ((uintptr_t)__builtin_return_address(0))
-# define GETPC_LDST() ((uintptr_t) ((*(int32_t *)(GETRA() + 4)) - 1))
+# define GETPC_LDST() ((uintptr_t) ((*(int32_t *)(GETRA() - 4)) - 1))
# else
# error "CONFIG_QEMU_LDST_OPTIMIZATION needs GETPC_LDST() implementation!"
# endif
diff --git a/tcg/ppc/tcg-target.c b/tcg/ppc/tcg-target.c
index a1c74ce..34a0693 100644
--- a/tcg/ppc/tcg-target.c
+++ b/tcg/ppc/tcg-target.c
@@ -569,6 +569,9 @@ static const void * const qemu_st_helpers[4] = {
helper_stq_mmu,
};
+static void *ld_trampolines[4];
+static void *st_trampolines[4];
+
static void tcg_out_tlb_check (TCGContext *s, int r0, int r1, int r2,
int addr_reg, int addr_reg2, int s_bits,
int offset1, int offset2, uint8_t **label_ptr)
@@ -848,8 +851,7 @@ static void tcg_out_qemu_ld_slow_path (TCGContext *s, TCGLabelQemuLdst *label)
reloc_pc14 (label_ptr[0], (tcg_target_long) s->code_ptr);
/* slow path */
- ir = 3;
- tcg_out_mov (s, TCG_TYPE_I32, ir++, TCG_AREG0);
+ ir = 4;
#if TARGET_LONG_BITS == 32
tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
#else
@@ -860,8 +862,7 @@ static void tcg_out_qemu_ld_slow_path (TCGContext *s, TCGLabelQemuLdst *label)
tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
#endif
tcg_out_movi (s, TCG_TYPE_I32, ir, mem_index);
- tcg_out_call (s, (tcg_target_long) qemu_ld_helpers[s_bits], 1);
- tcg_out32 (s, B | 8);
+ tcg_out_call (s, (tcg_target_long) ld_trampolines[s_bits], 1);
tcg_out32 (s, (tcg_target_long) raddr);
switch (opc) {
case 0|4:
@@ -916,8 +917,7 @@ static void tcg_out_qemu_st_slow_path (TCGContext *s, TCGLabelQemuLdst *label)
reloc_pc14 (label_ptr[0], (tcg_target_long) s->code_ptr);
/* slow path */
- ir = 3;
- tcg_out_mov (s, TCG_TYPE_I32, ir++, TCG_AREG0);
+ ir = 4;
#if TARGET_LONG_BITS == 32
tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
#else
@@ -959,8 +959,7 @@ static void tcg_out_qemu_st_slow_path (TCGContext *s, TCGLabelQemuLdst *label)
ir++;
tcg_out_movi (s, TCG_TYPE_I32, ir, mem_index);
- tcg_out_call (s, (tcg_target_long) qemu_st_helpers[opc], 1);
- tcg_out32 (s, B | 8);
+ tcg_out_call (s, (tcg_target_long) st_trampolines[opc], 1);
tcg_out32 (s, (tcg_target_long) raddr);
tcg_out_b (s, 0, (tcg_target_long) raddr);
}
@@ -983,6 +982,15 @@ void tcg_out_tb_finalize(TCGContext *s)
}
#endif
+static void emit_ldst_trampoline (TCGContext *s, const void *ptr)
+{
+ tcg_out32 (s, MFSPR | RT (3) | LR);
+ tcg_out32 (s, ADDI | RT (3) | RA (3) | 4);
+ tcg_out32 (s, MTSPR | RS (3) | LR);
+ tcg_out_mov (s, TCG_TYPE_I32, 3, TCG_AREG0);
+ tcg_out_b (s, 0, (tcg_target_long) ptr);
+}
+
static void tcg_target_qemu_prologue (TCGContext *s)
{
int i, frame_size;
@@ -1043,6 +1051,14 @@ static void tcg_target_qemu_prologue (TCGContext *s)
tcg_out32 (s, MTSPR | RS (0) | LR);
tcg_out32 (s, ADDI | RT (1) | RA (1) | frame_size);
tcg_out32 (s, BCLR | BO_ALWAYS);
+
+ for (i = 0; i < 4; ++i) {
+ ld_trampolines[i] = s->code_ptr;
+ emit_ldst_trampoline (s, qemu_ld_helpers[i]);
+
+ st_trampolines[i] = s->code_ptr;
+ emit_ldst_trampoline (s, qemu_st_helpers[i]);
+ }
}
static void tcg_out_ld (TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1,
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