Re: freedos under qemu failure with nvmm

[Ramiro Aceves <ea1abz%gmail.com@localhost>]

El 15/11/25 a las 9:54, Vitaly Shevtsov escribió:
> Oh... I hadn't seen your next message that dosbox is crashing.

Hi

It is crashing only in my i386 system that I have just upgraded to 
11.0_BETA, in amd64 10.1 works fine.

In amd64 I have problems with improved dosbox version, "dosbox-x". It 
fails to start, a workaround I found with the help of Chatgpt is to 
startx at 16 bit this way:

startx -- -depth 16



Regards.


> On Sat, Nov 15, 2025 at 1:52 PM Vitaly Shevtsov <shev.vt1984%gmail.com@localhost> wrote:
> > Hello, Ramiro.
> >
> > I don't know the reason. It looks like FreeDOS uses something that
> > other OSes don't use causing QEMU to crash.
> > But for me it happens only when FreeDOS is being installed. Once it's
> > installed I never face this issue. I'm pretty sure it's a bug in NVMM.
> > Maybe it's worth trying dosbox instead?
> >
> > On Thu, Nov 13, 2025 at 11:29 PM Ramiro Aceves <ea1abz%gmail.com@localhost> wrote:
> > > El 13/11/25 a las 19:19, Vitaly Shevtsov escribió:
> > > > Hello. I faced the same issue with qemu, nvmm and freedos. Tried to
> > > > debug with no luck. I found a workaround - run qemu with no
> > > > acceleration, install freedos, then run it with acceleration turned on.
> > > > This issue only happens when is it is being installed.
> > > >
> > > > чт, 13 нояб. 2025 г., 23:15 Ramiro Aceves <ea1abz%gmail.com@localhost
> > > > <mailto:ea1abz%gmail.com@localhost>>:
> > > >
> > > >
> > > >      Hello,
> > > >
> > > >      I tried to install FreeDOS under Qemu in NetBSD 10.1 using nvmm
> > > >      acceleration driver.
> > > >
> > > >
> > > >      I get an error like this when almost installed on the virtual disk:
> > > >
> > > >      qemu-system-i386: NVMM: Unexpected VM exit code 0xffffffffffffffff
> > > >      [hw=0x9]
> > > >      qemu-system-i386: NVMM: Failed to execute a VCPU.
> > > >      [1]   Abort trap (core dumped) qemu-system-i386 -m 64 -accel nvmm -
> > > >      smp 1
> > > >      -dri...
> > > >
> > > >
> > > >      I removed nvmm acceleration and I was able to end the installation
> > > >      without acceleration but it was painly slow.
> > > >
> > > >      I have been able to virtualize a full Debian GNU/Linux system using
> > > >      nvmm, no problems at all. Why nvmm fails with FreeDOS?
> > > >
> > > >      Thanks so much.
> > > >      Ramiro.
> > >
> > > Hello Vitaly,
> > >
> > > I have started the virtual FreeDOS with nvmm, it starts fast and well.
> > >
> > >
> > > c:\dir (file listing works fine)
> > >
> > > But when I start an editor:
> > >
> > >
> > > c:\EDIT
> > >
> > > qemu-system-i386: NVMM: Failed to execute a VCPU.
> > > [1]   Abort trap (core dumped) qemu-system-i386 -m 64 -accel nvmm -smp 1
> > > -dri...
> > > netbsd-nuc$
> > >
> > >
> > > Regards.
> > > Ramiro.
> > >
> > >
> > > >