[Qemu-devel] [Bug 1824768] [NEW] Qemu ARMv7 TCG MultiThreading for i386 guest doesn't work

[TimeMaster]

Public bug reported:

Using any Linux image (in this case Alpine Linux iso) I want to utilise
all cores of my Raspberry with --accel,thread=multi. I know there is a
probably still problem with memory ordering of the host, but I have also
seen some very old commits which could potentially help with it.

But anyway, with version qemu-i386 version 3.1.0 (Debian 1:3.1+dfsg-7)
I can see OpenRC starting up services and then the kernel crash.

With version QEMU emulator version 3.1.93 (v4.0.0-rc3-dirty)
The whole machine crash with this error:
Illegal instruction

Using command:
./qemu-system-i386 -cdrom alpine.iso --accel tcg,thread=multi

Full Console Output:
qemu-system-i386: warning: Guest expects a stronger memory ordering than the 
host provides
This may cause strange/hard to debug errors
Illegal instruction

Kernel:
Linux raspberrypi 4.14.98-v7+ #1200 SMP Tue Feb 12 20:27:48 GMT 2019 armv7l 
GNU/Linux

CPU:
ARMv7 Processor rev 5 (v7l)
Features: half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 
lpae evtstrm
4 cores

** Affects: qemu
     Importance: Undecided
         Status: New


** Tags: multithreading raspberry tcg

** Description changed:

- Using any Linux image (in this case Alpine Linux iso) and want to use
+ Using any Linux image (in this case Alpine Linux iso) I want to utilise
  all cores of my Raspberry with --accel,thread=multi. I know there is a
- probably still problem with memory ordering of the host but I have also
+ probably still problem with memory ordering of the host, but I have also
  seen some very old commits which could potentially help with it.
  
  But anyway, with version qemu-i386 version 3.1.0 (Debian 1:3.1+dfsg-7)
  I can see OpenRC starting up services and then the kernel crash.
  
  With version QEMU emulator version 3.1.93 (v4.0.0-rc3-dirty)
- The whole machine crash with this error: 
+ The whole machine crash with this error:
  Illegal instruction
- 
  
  Using command:
  ./qemu-system-i386 -cdrom alpine.iso --accel tcg,thread=multi
  
  Full Console Output:
  qemu-system-i386: warning: Guest expects a stronger memory ordering than the 
host provides
  This may cause strange/hard to debug errors
  Illegal instruction
  
- 
  Kernel:
  Linux raspberrypi 4.14.98-v7+ #1200 SMP Tue Feb 12 20:27:48 GMT 2019 armv7l 
GNU/Linux
  
  CPU:
  ARMv7 Processor rev 5 (v7l)
- Features: half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt 
vfpd32 lpae evtstrm 
+ Features: half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt 
vfpd32 lpae evtstrm
  4 cores

** Summary changed:

- Qemu ARMv7 TCG MultiThreading doesn't work
+ Qemu ARMv7 TCG MultiThreading for i386 guest doesn't work

-- 
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https://bugs.launchpad.net/bugs/1824768

Title:
  Qemu ARMv7 TCG MultiThreading for i386 guest doesn't work

Status in QEMU:
  New

Bug description:
  Using any Linux image (in this case Alpine Linux iso) I want to
  utilise all cores of my Raspberry with --accel,thread=multi. I know
  there is a probably still problem with memory ordering of the host,
  but I have also seen some very old commits which could potentially
  help with it.

  But anyway, with version qemu-i386 version 3.1.0 (Debian 1:3.1+dfsg-7)
  I can see OpenRC starting up services and then the kernel crash.

  With version QEMU emulator version 3.1.93 (v4.0.0-rc3-dirty)
  The whole machine crash with this error:
  Illegal instruction

  Using command:
  ./qemu-system-i386 -cdrom alpine.iso --accel tcg,thread=multi

  Full Console Output:
  qemu-system-i386: warning: Guest expects a stronger memory ordering than the 
host provides
  This may cause strange/hard to debug errors
  Illegal instruction

  Kernel:
  Linux raspberrypi 4.14.98-v7+ #1200 SMP Tue Feb 12 20:27:48 GMT 2019 armv7l 
GNU/Linux

  CPU:
  ARMv7 Processor rev 5 (v7l)
  Features: half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt 
vfpd32 lpae evtstrm
  4 cores

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