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  1. 12 11月, 2012 1 次提交
    • P
      scsi: do not return short responses for emulated commands · c8dcb531
      由 Paolo Bonzini 提交于 
      The inquiry command, for the case of VPD=1, was returning short
responses; the number of returned bytes was just the number of bytes
in the request, without padding to the specified allocation length
with zero bytes.  This is usually harmless, but it is a violation
of the SCSI specification.

To fix this, always pad with zero bytes to r->cmd.xfer in
scsi_disk_emulate_command, and return at most r->buflen bytes
(the size of the buffer for command data) rather than at most
buflen bytes (the number of bytes that was filled in).

Before this patch, "strace sg_inq -p0x83 /dev/sda" would report a
non-zero resid value.  After this patch, it reports resid=0.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      c8dcb531
  3. 11 11月, 2012 2 次提交
  5. 10 11月, 2012 14 次提交
  7. 09 11月, 2012 1 次提交
  9. 06 11月, 2012 2 次提交
    • P
      tools: initialize main loop before block layer · 2592c59a
      由 Paolo Bonzini 提交于 
      Tools were broken because they initialized the block layer while
qemu_aio_context was still NULL.
Reported-by: Nmalc <av1474@comtv.ru>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nmalc <av1474@comtv.ru>
      2592c59a
    • M
      tcg/ppc32: Use trampolines to trim the code size for mmu slow path accessors · c878da3b
      由 malc 提交于 
      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: Nmalc <av1474@comtv.ru>
      c878da3b
  11. 05 11月, 2012 2 次提交
  13. 04 11月, 2012 1 次提交
  15. 03 11月, 2012 17 次提交