[Bug 1902267] [NEW] CPU not support 32-bit stack in 32-bit unreal mode

[Bug 1902267] [NEW] CPU not support 32-bit stack in 32-bit unreal mode

[CandyMan]

Public bug reported:

QEMU version 5.0.0 supports 32-bit and 16-bit unreal mode. Great!
Unfortunately, QEMU does not support 32-bit stack in unreal 32-bit mode.
After the INT instruction, the stack is switched to 16-bit, which should not be the case. 
At BOCHS, my code works 100%. At QEMU not works.

Sample code to find out:

use32
cli
mov ax,cs
shl eax,16
mov ax,NewInt80h
mov [IDT32+4*80h],eax
mov edx,esp
mov esp,0x10000
int 80h
NewInt80h:
xchg esp,edx
cmp edx,0x10000-6
jnz IsStack16Bit

Stack selector loaded from GDT:
GDT:
real32_GDT            
dq 0
dw 0xFFFF,0x0000,9A00h,0xCF     ; 32-bit code descriptor
dw 0xFFFF,0x0000,9200h,0x8F     ;   4 GB data descriptor
dw 0xFFFF,0x0000,9A00h,0x00     ; 16-bit code descriptor
dw 0xFFFF,0x0000,9200h,0xCF     ; 32-bit data descriptor stack

** Affects: qemu
     Importance: Undecided
         Status: New

** Attachment added: "my operating system"
   https://bugs.launchpad.net/bugs/1902267/+attachment/5429520/+files/FLATDOS.IMG

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https://bugs.launchpad.net/bugs/1902267

Title:
  CPU not support 32-bit stack in 32-bit unreal mode

Status in QEMU:
  New

Bug description:
  QEMU version 5.0.0 supports 32-bit and 16-bit unreal mode. Great!
  Unfortunately, QEMU does not support 32-bit stack in unreal 32-bit mode.
  After the INT instruction, the stack is switched to 16-bit, which should not be the case. 
  At BOCHS, my code works 100%. At QEMU not works.

  Sample code to find out:

  use32
  cli
  mov ax,cs
  shl eax,16
  mov ax,NewInt80h
  mov [IDT32+4*80h],eax
  mov edx,esp
  mov esp,0x10000
  int 80h
  NewInt80h:
  xchg esp,edx
  cmp edx,0x10000-6
  jnz IsStack16Bit

  Stack selector loaded from GDT:
  GDT:
  real32_GDT            
  dq 0
  dw 0xFFFF,0x0000,9A00h,0xCF     ; 32-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0x8F     ;   4 GB data descriptor
  dw 0xFFFF,0x0000,9A00h,0x00     ; 16-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0xCF     ; 32-bit data descriptor stack

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[Bug 1902267] Re: CPU not support 32-bit stack in 32-bit unreal mode

[CandyMan]

** Attachment removed: "my operating system"
   https://bugs.launchpad.net/qemu/+bug/1902267/+attachment/5429520/+files/FLATDOS.IMG

** Attachment added: "my operating system"
   https://bugs.launchpad.net/qemu/+bug/1902267/+attachment/5429530/+files/FLATDOS.IMG

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1902267

Title:
  CPU not support 32-bit stack in 32-bit unreal mode

Status in QEMU:
  New

Bug description:
  QEMU version 5.0.0 supports 32-bit and 16-bit unreal mode. Great!
  Unfortunately, QEMU does not support 32-bit stack in unreal 32-bit mode.
  After the INT instruction, the stack is switched to 16-bit, which should not be the case. 
  At BOCHS, my code works 100%. At QEMU not works.

  Sample code to find out:

  use32
  cli
  mov ax,cs
  shl eax,16
  mov ax,NewInt80h
  mov [IDT32+4*80h],eax
  mov edx,esp
  mov esp,0x10000
  int 80h
  NewInt80h:
  xchg esp,edx
  cmp edx,0x10000-6
  jnz IsStack16Bit

  Stack selector loaded from GDT:
  GDT:
  real32_GDT            
  dq 0
  dw 0xFFFF,0x0000,9A00h,0xCF     ; 32-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0x8F     ;   4 GB data descriptor
  dw 0xFFFF,0x0000,9A00h,0x00     ; 16-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0xCF     ; 32-bit data descriptor stack

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[Bug 1902267] Re: CPU not support 32-bit stack in 32-bit unreal mode

[Thomas Huth]

The QEMU project is currently moving 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 the bug state to "Incomplete" now.

If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".

If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:

1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:

    https://gitlab.com/qemu-project/qemu/-/issues

and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.

2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" or "Confirmed" within the next 60 days (other-
wise it will get closed as "Expired"). We will then eventually migrate
the ticket automatically to the new system (but you won't be the reporter
of the bug in the new system and thus you won't get notified on changes
anymore).

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-
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https://bugs.launchpad.net/bugs/1902267

Title:
  CPU not support 32-bit stack in 32-bit unreal mode

Status in QEMU:
  Incomplete

Bug description:
  QEMU version 5.0.0 supports 32-bit and 16-bit unreal mode. Great!
  Unfortunately, QEMU does not support 32-bit stack in unreal 32-bit mode.
  After the INT instruction, the stack is switched to 16-bit, which should not be the case. 
  At BOCHS, my code works 100%. At QEMU not works.

  Sample code to find out:

  use32
  cli
  mov ax,cs
  shl eax,16
  mov ax,NewInt80h
  mov [IDT32+4*80h],eax
  mov edx,esp
  mov esp,0x10000
  int 80h
  NewInt80h:
  xchg esp,edx
  cmp edx,0x10000-6
  jnz IsStack16Bit

  Stack selector loaded from GDT:
  GDT:
  real32_GDT            
  dq 0
  dw 0xFFFF,0x0000,9A00h,0xCF     ; 32-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0x8F     ;   4 GB data descriptor
  dw 0xFFFF,0x0000,9A00h,0x00     ; 16-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0xCF     ; 32-bit data descriptor stack

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[Bug 1902267] Re: CPU not support 32-bit stack in 32-bit unreal mode

[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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https://bugs.launchpad.net/bugs/1902267

Title:
  CPU not support 32-bit stack in 32-bit unreal mode

Status in QEMU:
  Expired

Bug description:
  QEMU version 5.0.0 supports 32-bit and 16-bit unreal mode. Great!
  Unfortunately, QEMU does not support 32-bit stack in unreal 32-bit mode.
  After the INT instruction, the stack is switched to 16-bit, which should not be the case. 
  At BOCHS, my code works 100%. At QEMU not works.

  Sample code to find out:

  use32
  cli
  mov ax,cs
  shl eax,16
  mov ax,NewInt80h
  mov [IDT32+4*80h],eax
  mov edx,esp
  mov esp,0x10000
  int 80h
  NewInt80h:
  xchg esp,edx
  cmp edx,0x10000-6
  jnz IsStack16Bit

  Stack selector loaded from GDT:
  GDT:
  real32_GDT            
  dq 0
  dw 0xFFFF,0x0000,9A00h,0xCF     ; 32-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0x8F     ;   4 GB data descriptor
  dw 0xFFFF,0x0000,9A00h,0x00     ; 16-bit code descriptor
  dw 0xFFFF,0x0000,9200h,0xCF     ; 32-bit data descriptor stack

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