[Qemu-devel] [Bug 1783437] [NEW] read-modify-write page faults error code has write bit unset

[Qemu-devel] [Bug 1783437] [NEW] read-modify-write page faults error code has write bit unset

[Fabian Hemmer]

Public bug reported:

Consider the attached C file, which does a read-modify-write of the form
`add [mem], reg`, where `mem` points to a non-present page. In the
resulting page fault, the W/R bit is not set, while real hardware does
set this bit.

% gcc -m32 qemu-bug1.c&& ./a.out && qemu-i386 ./a.out
page fault: addr=0x70000000 err=0x6
page fault: addr=0x70000000 err=0x4

Tested on the qemu-3.0.0-rc1 release.

** Affects: qemu
     Importance: Undecided
         Status: New

** Attachment added: "qemu-bug1.c"
   https://bugs.launchpad.net/bugs/1783437/+attachment/5167345/+files/qemu-bug1.c

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https://bugs.launchpad.net/bugs/1783437

Title:
  read-modify-write page faults error code has write bit unset

Status in QEMU:
  New

Bug description:
  Consider the attached C file, which does a read-modify-write of the
  form `add [mem], reg`, where `mem` points to a non-present page. In
  the resulting page fault, the W/R bit is not set, while real hardware
  does set this bit.

  % gcc -m32 qemu-bug1.c&& ./a.out && qemu-i386 ./a.out
  page fault: addr=0x70000000 err=0x6
  page fault: addr=0x70000000 err=0x4

  Tested on the qemu-3.0.0-rc1 release.

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[Bug 1783437] Re: read-modify-write page faults error code has write bit unset

[Thomas Huth]

The QEMU project is currently considering to move its bug tracking to
another system. For this we need to know which bugs are still valid
and which could be closed already. Thus we are setting older bugs to
"Incomplete" now.

If you still think this bug report here is valid, then please switch
the state back to "New" within the next 60 days, otherwise this report
will be marked as "Expired". Or please mark it as "Fix Released" if
the problem has been solved with a newer version of QEMU already.

Thank you and sorry for the inconvenience.


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

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You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1783437

Title:
  read-modify-write page faults error code has write bit unset

Status in QEMU:
  Incomplete

Bug description:
  Consider the attached C file, which does a read-modify-write of the
  form `add [mem], reg`, where `mem` points to a non-present page. In
  the resulting page fault, the W/R bit is not set, while real hardware
  does set this bit.

  % gcc -m32 qemu-bug1.c&& ./a.out && qemu-i386 ./a.out
  page fault: addr=0x70000000 err=0x6
  page fault: addr=0x70000000 err=0x4

  Tested on the qemu-3.0.0-rc1 release.

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[Bug 1783437] Re: read-modify-write page faults error code has write bit unset

[Launchpad Bug Tracker]

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

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

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1783437

Title:
  read-modify-write page faults error code has write bit unset

Status in QEMU:
  Expired

Bug description:
  Consider the attached C file, which does a read-modify-write of the
  form `add [mem], reg`, where `mem` points to a non-present page. In
  the resulting page fault, the W/R bit is not set, while real hardware
  does set this bit.

  % gcc -m32 qemu-bug1.c&& ./a.out && qemu-i386 ./a.out
  page fault: addr=0x70000000 err=0x6
  page fault: addr=0x70000000 err=0x4

  Tested on the qemu-3.0.0-rc1 release.

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https://bugs.launchpad.net/qemu/+bug/1783437/+subscriptions