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

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

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@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 :/

OK :| IMHO upstream Xen maintainers should provide us a test, otherwise
we can not make our code base evolve.