Re: [PATCH] hw/i386/isapc: Remove dead Xen code

[Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>]

On 24/11/25 11:27, Mark Cave-Ayland wrote:
> On 23/11/2025 18:58, Philippe Mathieu-Daudé wrote:
>
> > We don't use Xen on the isapc machine: let's remove
> > pointless code.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
> > ---
> >   hw/i386/isapc.c | 27 ++++-----------------------
> >   1 file changed, 4 insertions(+), 23 deletions(-)
> >
> > diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
> > index 1ba9ae22cc3..1e13a30c505 100644
> > --- a/hw/i386/isapc.c
> > +++ b/hw/i386/isapc.c
> > @@ -17,8 +17,6 @@
> >   #include "hw/ide/ide-bus.h"
> >   #include "system/kvm.h"
> >   #include "hw/i386/kvm/clock.h"
> > -#include "hw/xen/xen-x86.h"
> > -#include "system/xen.h"
> >   #include "hw/rtc/mc146818rtc.h"
> >   #include "target/i386/cpu.h"
> > @@ -37,7 +35,6 @@ static void pc_init_isa(MachineState *machine)
> >       ISABus *isa_bus;
> >       uint32_t irq;
> >       GSIState *gsi_state;
> > -    MemoryRegion *ram_memory;
> >       DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
> >       int i;
> > @@ -77,15 +74,9 @@ static void pc_init_isa(MachineState *machine)
> >       /*
> >        * There is no RAM split for the isapc machine
> >        */
> > -    if (xen_enabled()) {
> > -        xen_hvm_init_pc(pcms, &ram_memory);
> > -    } else {
> > -        ram_memory = machine->ram;
> > -
> > -        pcms->max_ram_below_4g = 3.5 * GiB;
> > -        x86ms->above_4g_mem_size = 0;
> > -        x86ms->below_4g_mem_size = machine->ram_size;
> > -    }
> > +    pcms->max_ram_below_4g = 3.5 * GiB;
> > +    x86ms->above_4g_mem_size = 0;
> > +    x86ms->below_4g_mem_size = machine->ram_size;
> >       x86_cpus_init(x86ms, pcmc->default_cpu_version);
> > @@ -94,17 +85,7 @@ static void pc_init_isa(MachineState *machine)
> >       }
> >       /* allocate ram and load rom/bios */
> > -    if (!xen_enabled()) {
> > -        pc_memory_init(pcms, system_memory, system_memory, 0);
> > -    } else {
> > -        assert(machine->ram_size == x86ms->below_4g_mem_size +
> > -                                    x86ms->above_4g_mem_size);
> > -
> > -        if (machine->kernel_filename != NULL) {
> > -            /* For xen HVM direct kernel boot, load linux here */
> > -            xen_load_linux(pcms);
> > -        }
> > -    }
> > +    pc_memory_init(pcms, system_memory, system_memory, 0);
> >       gsi_state = pc_gsi_create(&x86ms->gsi, false);
> FWIW I did contact upstream about this (see https://patchew.org/ 
> QEMU/20250618112828.235087-1- 
> mark.caveayland@xxxxxxxxxxx/20250618112828.235087-13- 
> mark.caveayland@xxxxxxxxxxx/#91b96b24-af60-4a89-91ec- 
> d0e660a76a0a@xxxxxxxxxxx) and they mentioned that it should work, which 
> is why I left it in.
> Unfortunately I don't currently have any way to test it here :/
OK :| IMHO upstream Xen maintainers should provide us a test, otherwise
we can not make our code base evolve.