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  1. May 18, 2023
    • Paolo Bonzini's avatar
      target/i386: fix operand size for VCOMI/VUCOMI instructions · 2b55e479
      Paolo Bonzini authored
      
      Compared to other SSE instructions, VUCOMISx and VCOMISx are different:
      the single and double precision versions are distinguished through a
      prefix, however they use no-prefix and 0x66 for SS and SD respectively.
      Scalar values usually are associated with 0xF2 and 0xF3.
      
      Because of these, they incorrectly perform a 128-bit memory load instead
      of a 32- or 64-bit load.  Fix this by writing a custom decoding function.
      
      I tested that the reproducer is fixed and the test-avx output does not
      change.
      
      Reported-by: default avatarGabriele Svelto <gsvelto@mozilla.com>
      Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1637
      
      
      Fixes: f8d19eec ("target/i386: reimplement 0x0f 0x28-0x2f, add AVX", 2022-10-18)
      Cc: qemu-stable@nongnu.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      2b55e479
    • Emanuele Giuseppe Esposito's avatar
      target/i386: add support for FB_CLEAR feature · 22e1094c
      Emanuele Giuseppe Esposito authored
      
      As reported by the Intel's doc:
      "FB_CLEAR: The processor will overwrite fill buffer values as part of
      MD_CLEAR operations with the VERW instruction.
      On these processors, L1D_FLUSH does not overwrite fill buffer values."
      
      If this cpu feature is present in host, allow QEMU to choose whether to
      show it to the guest too.
      One disadvantage of not exposing it is that the guest will report
      a non existing vulnerability in
      /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
      because the mitigation is present only when the cpu has
              (FLUSH_L1D and MD_CLEAR) or FB_CLEAR
      features enabled.
      
      Signed-off-by: default avatarEmanuele Giuseppe Esposito <eesposit@redhat.com>
      Message-Id: <20230201135759.555607-3-eesposit@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      22e1094c
    • Emanuele Giuseppe Esposito's avatar
      target/i386: add support for FLUSH_L1D feature · 0e7e3bf1
      Emanuele Giuseppe Esposito authored
      
      As reported by Intel's doc:
      "L1D_FLUSH: Writeback and invalidate the L1 data cache"
      
      If this cpu feature is present in host, allow QEMU to choose whether to
      show it to the guest too.
      One disadvantage of not exposing it is that the guest will report
      a non existing vulnerability in
      /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
      because the mitigation is present only when the cpu has
      	(FLUSH_L1D and MD_CLEAR) or FB_CLEAR
      features enabled.
      
      Signed-off-by: default avatarEmanuele Giuseppe Esposito <eesposit@redhat.com>
      Message-Id: <20230201135759.555607-2-eesposit@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      0e7e3bf1
  2. May 17, 2023
  3. May 16, 2023
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