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

[Mark Cave-Ayland <mark.caveayland@nutanix.com>]

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@linaro.org>
> ---
>   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@nutanix.com/20250618112828.235087-13-mark.caveayland@nutanix.com/#91b96b24-af60-4a89-91ec-d0e660a76a0a@nutanix.com) 
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 :/


ATB,

Mark.