[Qemu-devel] [Bug 1245543] [NEW] Wrong implementation of SSE4.1 pmovzxbw and similar instructions

[Qemu-devel] [Bug 1245543] [NEW] Wrong implementation of SSE4.1 pmovzxbw and similar instructions

[p12]

Public bug reported:

QEMU 1.5.0 (and git version, as far as I can tell from the source code)
has incorrect implementation of pmovzxbw and similar SSE4.1
instructions. The instruction zero-extends the first 8 8-bit elements of
a vector to 16bit vector and puts them to another vector. The current
implementation applies this operation only to the first element and
zeros out the rest.

To verify, compile the attached program for SSE4.1 (g++ -msse4.1
cvtint.cc). On real hardware, it produces the following output:

$ ./a.out
1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0

On QEMU, the output is as follows:

$ ./a.out
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

QEMU is invoked as:

qemu-system-x86_64 \
    -M pc -cpu Haswell,+sse4.1,+avx,+avx2,+fma,enforce -m 512 \
    -serial stdio -no-reboot \
    -kernel vmlinuz -initrd initrd.img \
    -netdev user,id=user.0 -device rtl8139,netdev=user.0  -redir tcp:2222::22 \
    -hda ubuntu-amd64.ext3 \
    --append "rw console=tty root=/dev/sda"

** Affects: qemu
     Importance: Undecided
         Status: New

** Attachment added: "Program to verify this bug"
   https://bugs.launchpad.net/bugs/1245543/+attachment/3893823/+files/cvtint.cc

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Title:
  Wrong implementation of SSE4.1 pmovzxbw and similar instructions

Status in QEMU:
  New

Bug description:
  QEMU 1.5.0 (and git version, as far as I can tell from the source
  code) has incorrect implementation of pmovzxbw and similar SSE4.1
  instructions. The instruction zero-extends the first 8 8-bit elements
  of a vector to 16bit vector and puts them to another vector. The
  current implementation applies this operation only to the first
  element and zeros out the rest.

  To verify, compile the attached program for SSE4.1 (g++ -msse4.1
  cvtint.cc). On real hardware, it produces the following output:

  $ ./a.out
  1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0

  On QEMU, the output is as follows:

  $ ./a.out
  1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

  QEMU is invoked as:

  qemu-system-x86_64 \
      -M pc -cpu Haswell,+sse4.1,+avx,+avx2,+fma,enforce -m 512 \
      -serial stdio -no-reboot \
      -kernel vmlinuz -initrd initrd.img \
      -netdev user,id=user.0 -device rtl8139,netdev=user.0  -redir tcp:2222::22 \
      -hda ubuntu-amd64.ext3 \
      --append "rw console=tty root=/dev/sda"

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[Bug 1245543] Re: Wrong implementation of SSE4.1 pmovzxbw and similar instructions

[Thomas Huth]

Looking through old bug tickets... is this still an issue with the
latest version of QEMU? Or could we close this ticket nowadays?

** Changed in: qemu
       Status: New => Incomplete

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Title:
  Wrong implementation of SSE4.1 pmovzxbw and similar instructions

Status in QEMU:
  Incomplete

Bug description:
  QEMU 1.5.0 (and git version, as far as I can tell from the source
  code) has incorrect implementation of pmovzxbw and similar SSE4.1
  instructions. The instruction zero-extends the first 8 8-bit elements
  of a vector to 16bit vector and puts them to another vector. The
  current implementation applies this operation only to the first
  element and zeros out the rest.

  To verify, compile the attached program for SSE4.1 (g++ -msse4.1
  cvtint.cc). On real hardware, it produces the following output:

  $ ./a.out
  1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0

  On QEMU, the output is as follows:

  $ ./a.out
  1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

  QEMU is invoked as:

  qemu-system-x86_64 \
      -M pc -cpu Haswell,+sse4.1,+avx,+avx2,+fma,enforce -m 512 \
      -serial stdio -no-reboot \
      -kernel vmlinuz -initrd initrd.img \
      -netdev user,id=user.0 -device rtl8139,netdev=user.0  -redir tcp:2222::22 \
      -hda ubuntu-amd64.ext3 \
      --append "rw console=tty root=/dev/sda"

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https://bugs.launchpad.net/qemu/+bug/1245543/+subscriptions

[Bug 1245543] Re: Wrong implementation of SSE4.1 pmovzxbw and similar instructions

[Launchpad Bug Tracker]

[Expired for QEMU because there has been no activity for 60 days.]

** Changed in: qemu
       Status: Incomplete => Expired

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Title:
  Wrong implementation of SSE4.1 pmovzxbw and similar instructions

Status in QEMU:
  Expired

Bug description:
  QEMU 1.5.0 (and git version, as far as I can tell from the source
  code) has incorrect implementation of pmovzxbw and similar SSE4.1
  instructions. The instruction zero-extends the first 8 8-bit elements
  of a vector to 16bit vector and puts them to another vector. The
  current implementation applies this operation only to the first
  element and zeros out the rest.

  To verify, compile the attached program for SSE4.1 (g++ -msse4.1
  cvtint.cc). On real hardware, it produces the following output:

  $ ./a.out
  1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0

  On QEMU, the output is as follows:

  $ ./a.out
  1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

  QEMU is invoked as:

  qemu-system-x86_64 \
      -M pc -cpu Haswell,+sse4.1,+avx,+avx2,+fma,enforce -m 512 \
      -serial stdio -no-reboot \
      -kernel vmlinuz -initrd initrd.img \
      -netdev user,id=user.0 -device rtl8139,netdev=user.0  -redir tcp:2222::22 \
      -hda ubuntu-amd64.ext3 \
      --append "rw console=tty root=/dev/sda"

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https://bugs.launchpad.net/qemu/+bug/1245543/+subscriptions