Re: [Dosemu-devel] Is DOSEMU2 intended running on kernels like 3.2 ?

[Andrew B. <aj...@sp...>]

On Tue, 22 Dec 2015 11:34:26 +0100
bo...@ge... wrote:

> Hello
> 
> I've compiled the DOSEMU2 devel branch (2.0pre4, 1893) on an Ubuntu 
> 12.04 LTS (x86 / 32-bit / PAE). This fails due to the usage of 
> "X86_EFLAGS_FIXED" in the file "src/emu-i386/kvm.c".
> 
> I believe that the define of "X86_EFLAGS_FIXED" is missing in the kernel 
> 3.2 of my Ubuntu version. There has been a rename of "X86_EFLAGS_BIT1" 
> to "X86_EFLAGS_FIXED" some time ago:
> 
> https://www.kernel.org/pub/linux/kernel/v3.0/ChangeLog-3.10.60
> 
> 
> In the meantime, I added the following line to "kvm.c" and could compile 
> successfully DOSEMU2:
> 
> #define X86_EFLAGS_FIXED                0x00000002
> 
> But I believe, this is NOT the right thing... DOSEMU2 runs, but I use 
> "vm86" and not "kvm".
> 
> 
> So, coming back to the subject of this message:
> 
> Is DOSEMU2 supposed to work on older Linux Kernels ? If not, then this 
> message can be sent to device null.
> 
> Andreas
> 
> 

Hi Andreas,
    Firstly you should raise an issue at https://github.com/stsp/dosemu2/issues as it'll get tracked properly there and Stas / Bart won't miss it. Regarding use of vm86, I think on 386 kernels it's still the default, so are you forcing it to try kvm? There's a new dosemu.conf variable called $_cpu_vm since kvm support got added. Here's the section from the default dosemu.conf. 

# Usage of cpu emulation: "off" (default on x86),                               
# "vm86" only (default on x86-64) or "full" (vm86 and DPMI, experimental!).     
# Use "vm86sim" or "fullsim" to use simulation instead of JIT code generation.  
                                                                                
# $_cpu_emu = "off"                                                             
                                                                                
# Select cpu virtualization mode.                                               
# "vm86" - use v86 mode via vm86() syscall. Only available on x86-32.           
# "kvm" - use KVM, hardware-assisted in-kernel virtual machine.                 
# "emulated" - use CPU emulator                                                 
# "auto" - select whatever works                                                
                                                                                
# $_cpu_vm = "auto"

Remember that kvm support requires a certain processor type to work, but in any case you should raise the issue because dosemu2 should definitely compile on kernel 3.2 without changes.


-- 
Andrew Bird <aj...@sp...>