[Qemu-devel] [Bug 1078892] Re: qemu doesn't general protection fault if there are reserved bits set in page-directory-pointer table entries

[Thomas Huth]

Triaging old bug tickets ... can you still reproduce this issue with the
latest version of QEMU (version 2.9)?

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

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https://bugs.launchpad.net/bugs/1078892

Title:
  qemu doesn't general protection fault if there are reserved bits set
  in page-directory-pointer table entries

Status in QEMU:
  Incomplete

Bug description:
  While working on implementing 32-bit PAE mode in a custom operating
  system, which I was testing in QEMU, I noticed that my OS worked
  correctly, but resulted in a general protection fault when booted on
  VMware, VirtualBox, or bochs.

  According to the Intel Architecture Manual, Volume 3A, Section 4.4.1
  "PDPTE Registers", "If any of the PDPTEs sets both the P flag (bit 0)
  and any reserved bit, the MOV to CR instruction causes a general-
  protection exception (#GP(0)) and the PDPTEs are not loaded." QEMU
  does not emulate this behavior.

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