[PATCH v4 18/18] hw/i386/isapc.c: replace rom_memory with system_memory

Mark Cave-Ayland posted 18 patches 4 months, 1 week ago
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>
There is a newer version of this series
[PATCH v4 18/18] hw/i386/isapc.c: replace rom_memory with system_memory
Posted by Mark Cave-Ayland 4 months, 1 week ago
Now that we can guarantee the isapc machine will never have a PCI bus, any
instances of rom_memory can be replaced by system_memory and rom_memory
removed completely.

Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
---
 hw/i386/isapc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
index bb22083821..27c075b5f3 100644
--- a/hw/i386/isapc.c
+++ b/hw/i386/isapc.c
@@ -35,7 +35,6 @@ static void pc_init_isa(MachineState *machine)
     ISABus *isa_bus;
     GSIState *gsi_state;
     MemoryRegion *ram_memory;
-    MemoryRegion *rom_memory = system_memory;
     DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
     uint32_t irq;
     int i;
@@ -73,7 +72,7 @@ static void pc_init_isa(MachineState *machine)
 
     /* allocate ram and load rom/bios */
     if (!xen_enabled()) {
-        pc_memory_init(pcms, system_memory, rom_memory, 0);
+        pc_memory_init(pcms, system_memory, system_memory, 0);
     } else {
         assert(machine->ram_size == x86ms->below_4g_mem_size +
                                     x86ms->above_4g_mem_size);
-- 
2.43.0
Re: [PATCH v4 18/18] hw/i386/isapc.c: replace rom_memory with system_memory
Posted by Philippe Mathieu-Daudé 4 months, 1 week ago
On 10/7/25 10:52, Mark Cave-Ayland wrote:
> Now that we can guarantee the isapc machine will never have a PCI bus, any
> instances of rom_memory can be replaced by system_memory and rom_memory
> removed completely.
> 
> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
> ---
>   hw/i386/isapc.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
> index bb22083821..27c075b5f3 100644
> --- a/hw/i386/isapc.c
> +++ b/hw/i386/isapc.c
> @@ -35,7 +35,6 @@ static void pc_init_isa(MachineState *machine)
>       ISABus *isa_bus;
>       GSIState *gsi_state;
>       MemoryRegion *ram_memory;
> -    MemoryRegion *rom_memory = system_memory;
>       DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
>       uint32_t irq;
>       int i;
> @@ -73,7 +72,7 @@ static void pc_init_isa(MachineState *machine)
>   
>       /* allocate ram and load rom/bios */
>       if (!xen_enabled()) {
> -        pc_memory_init(pcms, system_memory, rom_memory, 0);
> +        pc_memory_init(pcms, system_memory, system_memory, 0);

I'd prefer just call here:

   x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);

and in pc_system_firmware_init(): assert(pcmc->pci_enabled).

WDYT?

>       } else {
>           assert(machine->ram_size == x86ms->below_4g_mem_size +
>                                       x86ms->above_4g_mem_size);
Re: [PATCH v4 18/18] hw/i386/isapc.c: replace rom_memory with system_memory
Posted by Philippe Mathieu-Daudé 4 months, 1 week ago
On 10/7/25 12:53, Philippe Mathieu-Daudé wrote:
> On 10/7/25 10:52, Mark Cave-Ayland wrote:
>> Now that we can guarantee the isapc machine will never have a PCI bus, 
>> any
>> instances of rom_memory can be replaced by system_memory and rom_memory
>> removed completely.
>>
>> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
>> ---
>>   hw/i386/isapc.c | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
>> index bb22083821..27c075b5f3 100644
>> --- a/hw/i386/isapc.c
>> +++ b/hw/i386/isapc.c
>> @@ -35,7 +35,6 @@ static void pc_init_isa(MachineState *machine)
>>       ISABus *isa_bus;
>>       GSIState *gsi_state;
>>       MemoryRegion *ram_memory;
>> -    MemoryRegion *rom_memory = system_memory;
>>       DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
>>       uint32_t irq;
>>       int i;
>> @@ -73,7 +72,7 @@ static void pc_init_isa(MachineState *machine)
>>       /* allocate ram and load rom/bios */
>>       if (!xen_enabled()) {
>> -        pc_memory_init(pcms, system_memory, rom_memory, 0);
>> +        pc_memory_init(pcms, system_memory, system_memory, 0);
> 
> I'd prefer just call here:
> 
>    x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
> 
> and in pc_system_firmware_init(): assert(pcmc->pci_enabled).
> 
> WDYT?

What I have in mind (untested):

-- >8 --
diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
index 27c075b5f32..a7c2146916c 100644
--- a/hw/i386/isapc.c
+++ b/hw/i386/isapc.c
@@ -74,3 +74,4 @@ static void pc_init_isa(MachineState *machine)
      if (!xen_enabled()) {
-        pc_memory_init(pcms, system_memory, system_memory, 0);
+        pc_memory_init(pcms, system_memory, NULL, 0);
+        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", system_memory, 
true);
      } else {
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index b2116335752..2952d3ee4ff 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -811,3 +811,3 @@ void pc_memory_init(PCMachineState *pcms,
                      MemoryRegion *system_memory,
-                    MemoryRegion *rom_memory,
+                    MemoryRegion *pci_memory,
                      uint64_t pci_hole64_size)
@@ -826,2 +826,3 @@ void pc_memory_init(PCMachineState *pcms,

+    assert(pcmc->pci_enabled ^ !!pci_memory);
      assert(machine->ram_size == x86ms->below_4g_mem_size +
@@ -955,3 +956,5 @@ void pc_memory_init(PCMachineState *pcms,
      /* Initialize PC system firmware */
-    pc_system_firmware_init(pcms, rom_memory);
+    if (pcmc->pci_enabled) {
+        pc_system_firmware_init(pcms, pci_memory);
+    }

@@ -969,3 +972,3 @@ void pc_memory_init(PCMachineState *pcms,
          }
-        memory_region_add_subregion_overlap(rom_memory,
+        memory_region_add_subregion_overlap(pci_memory,
                                              PC_ROM_MIN_VGA,
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 821396c16e9..0c29e4188fc 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -221,6 +221,3 @@ void pc_system_firmware_init(PCMachineState *pcms,

-    if (!pcmc->pci_enabled) {
-        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
-        return;
-    }
+    assert(pcmc->pci_enabled);

---

Re: [PATCH v4 18/18] hw/i386/isapc.c: replace rom_memory with system_memory
Posted by Mark Cave-Ayland 4 months, 1 week ago
On 10/07/2025 12:05, Philippe Mathieu-Daudé wrote:

> On 10/7/25 12:53, Philippe Mathieu-Daudé wrote:
>> On 10/7/25 10:52, Mark Cave-Ayland wrote:
>>> Now that we can guarantee the isapc machine will never have a PCI 
>>> bus, any
>>> instances of rom_memory can be replaced by system_memory and rom_memory
>>> removed completely.
>>>
>>> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
>>> ---
>>>   hw/i386/isapc.c | 3 +--
>>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>>
>>> diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
>>> index bb22083821..27c075b5f3 100644
>>> --- a/hw/i386/isapc.c
>>> +++ b/hw/i386/isapc.c
>>> @@ -35,7 +35,6 @@ static void pc_init_isa(MachineState *machine)
>>>       ISABus *isa_bus;
>>>       GSIState *gsi_state;
>>>       MemoryRegion *ram_memory;
>>> -    MemoryRegion *rom_memory = system_memory;
>>>       DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
>>>       uint32_t irq;
>>>       int i;
>>> @@ -73,7 +72,7 @@ static void pc_init_isa(MachineState *machine)
>>>       /* allocate ram and load rom/bios */
>>>       if (!xen_enabled()) {
>>> -        pc_memory_init(pcms, system_memory, rom_memory, 0);
>>> +        pc_memory_init(pcms, system_memory, system_memory, 0);
>>
>> I'd prefer just call here:
>>
>>    x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
>>
>> and in pc_system_firmware_init(): assert(pcmc->pci_enabled).
>>
>> WDYT?
> 
> What I have in mind (untested):
> 
> -- >8 --
> diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
> index 27c075b5f32..a7c2146916c 100644
> --- a/hw/i386/isapc.c
> +++ b/hw/i386/isapc.c
> @@ -74,3 +74,4 @@ static void pc_init_isa(MachineState *machine)
>       if (!xen_enabled()) {
> -        pc_memory_init(pcms, system_memory, system_memory, 0);
> +        pc_memory_init(pcms, system_memory, NULL, 0);
> +        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", system_memory, 
> true);
>       } else {
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index b2116335752..2952d3ee4ff 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -811,3 +811,3 @@ void pc_memory_init(PCMachineState *pcms,
>                       MemoryRegion *system_memory,
> -                    MemoryRegion *rom_memory,
> +                    MemoryRegion *pci_memory,
>                       uint64_t pci_hole64_size)
> @@ -826,2 +826,3 @@ void pc_memory_init(PCMachineState *pcms,
> 
> +    assert(pcmc->pci_enabled ^ !!pci_memory);
>       assert(machine->ram_size == x86ms->below_4g_mem_size +
> @@ -955,3 +956,5 @@ void pc_memory_init(PCMachineState *pcms,
>       /* Initialize PC system firmware */
> -    pc_system_firmware_init(pcms, rom_memory);
> +    if (pcmc->pci_enabled) {
> +        pc_system_firmware_init(pcms, pci_memory);
> +    }
> 
> @@ -969,3 +972,3 @@ void pc_memory_init(PCMachineState *pcms,
>           }
> -        memory_region_add_subregion_overlap(rom_memory,
> +        memory_region_add_subregion_overlap(pci_memory,
>                                               PC_ROM_MIN_VGA,
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index 821396c16e9..0c29e4188fc 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -221,6 +221,3 @@ void pc_system_firmware_init(PCMachineState *pcms,
> 
> -    if (!pcmc->pci_enabled) {
> -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, 
> true);
> -        return;
> -    }
> +    assert(pcmc->pci_enabled);

I think that's a good idea, however the original aim of this series was 
just to do the basic split and tidy-up work (hopefully in time for 10.1).

There is certainly more tidy-up that is possible w.r.t. pc.c, but I 
didn't want to start unraveling that thread right now for fear of this 
series getting too large :/


ATB,

Mark.


Re: [PATCH v4 18/18] hw/i386/isapc.c: replace rom_memory with system_memory
Posted by Philippe Mathieu-Daudé 4 months, 1 week ago
On 10/7/25 17:35, Mark Cave-Ayland wrote:
> On 10/07/2025 12:05, Philippe Mathieu-Daudé wrote:
> 
>> On 10/7/25 12:53, Philippe Mathieu-Daudé wrote:
>>> On 10/7/25 10:52, Mark Cave-Ayland wrote:
>>>> Now that we can guarantee the isapc machine will never have a PCI 
>>>> bus, any
>>>> instances of rom_memory can be replaced by system_memory and rom_memory
>>>> removed completely.
>>>>
>>>> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
>>>> ---
>>>>   hw/i386/isapc.c | 3 +--
>>>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>> diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
>>>> index bb22083821..27c075b5f3 100644
>>>> --- a/hw/i386/isapc.c
>>>> +++ b/hw/i386/isapc.c
>>>> @@ -35,7 +35,6 @@ static void pc_init_isa(MachineState *machine)
>>>>       ISABus *isa_bus;
>>>>       GSIState *gsi_state;
>>>>       MemoryRegion *ram_memory;
>>>> -    MemoryRegion *rom_memory = system_memory;
>>>>       DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
>>>>       uint32_t irq;
>>>>       int i;
>>>> @@ -73,7 +72,7 @@ static void pc_init_isa(MachineState *machine)
>>>>       /* allocate ram and load rom/bios */
>>>>       if (!xen_enabled()) {
>>>> -        pc_memory_init(pcms, system_memory, rom_memory, 0);
>>>> +        pc_memory_init(pcms, system_memory, system_memory, 0);
>>>
>>> I'd prefer just call here:
>>>
>>>    x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, true);
>>>
>>> and in pc_system_firmware_init(): assert(pcmc->pci_enabled).
>>>
>>> WDYT?
>>
>> What I have in mind (untested):
>>
>> -- >8 --
>> diff --git a/hw/i386/isapc.c b/hw/i386/isapc.c
>> index 27c075b5f32..a7c2146916c 100644
>> --- a/hw/i386/isapc.c
>> +++ b/hw/i386/isapc.c
>> @@ -74,3 +74,4 @@ static void pc_init_isa(MachineState *machine)
>>       if (!xen_enabled()) {
>> -        pc_memory_init(pcms, system_memory, system_memory, 0);
>> +        pc_memory_init(pcms, system_memory, NULL, 0);
>> +        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", 
>> system_memory, true);
>>       } else {
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index b2116335752..2952d3ee4ff 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -811,3 +811,3 @@ void pc_memory_init(PCMachineState *pcms,
>>                       MemoryRegion *system_memory,
>> -                    MemoryRegion *rom_memory,
>> +                    MemoryRegion *pci_memory,
>>                       uint64_t pci_hole64_size)
>> @@ -826,2 +826,3 @@ void pc_memory_init(PCMachineState *pcms,
>>
>> +    assert(pcmc->pci_enabled ^ !!pci_memory);
>>       assert(machine->ram_size == x86ms->below_4g_mem_size +
>> @@ -955,3 +956,5 @@ void pc_memory_init(PCMachineState *pcms,
>>       /* Initialize PC system firmware */
>> -    pc_system_firmware_init(pcms, rom_memory);
>> +    if (pcmc->pci_enabled) {
>> +        pc_system_firmware_init(pcms, pci_memory);
>> +    }
>>
>> @@ -969,3 +972,3 @@ void pc_memory_init(PCMachineState *pcms,
>>           }
>> -        memory_region_add_subregion_overlap(rom_memory,
>> +        memory_region_add_subregion_overlap(pci_memory,
>>                                               PC_ROM_MIN_VGA,
>> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
>> index 821396c16e9..0c29e4188fc 100644
>> --- a/hw/i386/pc_sysfw.c
>> +++ b/hw/i386/pc_sysfw.c
>> @@ -221,6 +221,3 @@ void pc_system_firmware_init(PCMachineState *pcms,
>>
>> -    if (!pcmc->pci_enabled) {
>> -        x86_bios_rom_init(X86_MACHINE(pcms), "bios.bin", rom_memory, 
>> true);
>> -        return;
>> -    }
>> +    assert(pcmc->pci_enabled);
> 
> I think that's a good idea, however the original aim of this series was 
> just to do the basic split and tidy-up work (hopefully in time for 10.1).
> 
> There is certainly more tidy-up that is possible w.r.t. pc.c, but I 
> didn't want to start unraveling that thread right now for fear of this 
> series getting too large :/

Fair enough.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>