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From: Mingye Wang <1912107@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1912107] [NEW] Option to constrain linux-user exec() to emulated CPU only
Date: Sun, 17 Jan 2021 18:37:00 -0000	[thread overview]
Message-ID: <161090862069.30717.14713485848942415507.malonedeb@chaenomeles.canonical.com> (raw)

Public bug reported:

When trying to reproduce a bug someone reported on an actual AMD K10[1], ​I tried to directly throw `qemu_x86-64 -cpu 
​phenom path/to/wrongly-labelled-instruction-set/gcc 1.c` at the problem, but failed to get an "illegal instruction" as expected. A quick investigation reveals that the error is actually caused by one of gcc's child processess, and that the said process is being ran directly on the host. A similar problem happens with trying to call stuff with /usr/bin/env.

 ​[1]: https://github.com/Homebrew/brew/issues/1034

Since both the host and the guest are x86_64, I deemed binfmt
inapplicable to my case. I believe that QEMU should offer a way to
modify exec() and other spawning syscalls so that execution remains on
an emulated CPU in such a case. Call it an extra layer of binfmt, if you
must.

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1912107

Title:
  Option to constrain linux-user exec() to emulated CPU only

Status in QEMU:
  New

Bug description:
  When trying to reproduce a bug someone reported on an actual AMD K10[1], ​I tried to directly throw `qemu_x86-64 -cpu 
  ​phenom path/to/wrongly-labelled-instruction-set/gcc 1.c` at the problem, but failed to get an "illegal instruction" as expected. A quick investigation reveals that the error is actually caused by one of gcc's child processess, and that the said process is being ran directly on the host. A similar problem happens with trying to call stuff with /usr/bin/env.

   ​[1]: https://github.com/Homebrew/brew/issues/1034

  Since both the host and the guest are x86_64, I deemed binfmt
  inapplicable to my case. I believe that QEMU should offer a way to
  modify exec() and other spawning syscalls so that execution remains on
  an emulated CPU in such a case. Call it an extra layer of binfmt, if
  you must.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912107/+subscriptions


             reply	other threads:[~2021-01-17 18:47 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-17 18:37 Mingye Wang [this message]
2021-05-12 11:24 ` [Bug 1912107] Re: Option to constrain linux-user exec() to emulated CPU only Thomas Huth
2021-05-13 13:23 ` Mingye Wang
2021-05-14 19:28 ` Thomas Huth

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