Re: [PATCH v2 4/4] hw/display: Remove "rombar" hack from vga-pci and vmware_vga

[Thomas Huth <thuth@redhat.com>]

On 09/12/2019 14.30, Paolo Bonzini wrote:
> On 09/12/19 14:12, Philippe Mathieu-Daudé wrote:
>> On 12/9/19 1:52 PM, Thomas Huth wrote:
>>> Now that the old pc-0.x machine types have been removed, we do not need
>>> the old "rombar" hacks anymore.
>>>
>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>> ---
>>>   hw/display/vga-pci.c    | 5 -----
>>>   hw/display/vga.c        | 4 +---
>>>   hw/display/vmware_vga.c | 5 -----
>>>   3 files changed, 1 insertion(+), 13 deletions(-)
>>>
>>> diff --git a/hw/display/vga-pci.c b/hw/display/vga-pci.c
>>> index a27b88122d..cfe095713e 100644
>>> --- a/hw/display/vga-pci.c
>>> +++ b/hw/display/vga-pci.c
>>> @@ -264,11 +264,6 @@ static void pci_std_vga_realize(PCIDevice *dev,
>>> Error **errp)
>>>             pci_register_bar(&d->dev, 2,
>>> PCI_BASE_ADDRESS_SPACE_MEMORY, &d->mmio);
>>>       }
>>> -
>>> -    if (!dev->rom_bar) {
>>> -        /* compatibility with pc-0.13 and older */
>>> -        vga_init_vbe(s, OBJECT(dev), pci_address_space(dev));
>>> -    }
>>>   }
>>>     static void pci_std_vga_init(Object *obj)
>>> diff --git a/hw/display/vga.c b/hw/display/vga.c
>>> index 82ebe53610..636586a476 100644
>>> --- a/hw/display/vga.c
>>> +++ b/hw/display/vga.c
>>> @@ -2304,9 +2304,7 @@ void vga_init(VGACommonState *s, Object *obj,
>>> MemoryRegion *address_space,
>>>     void vga_init_vbe(VGACommonState *s, Object *obj, MemoryRegion
>>> *system_memory)
>>>   {
>>> -    /* With pc-0.12 and below we map both the PCI BAR and the fixed
>>> VBE region,
>>> -     * so use an alias to avoid double-mapping the same region.
>>> -     */
>>> +    /* Use an alias to avoid double-mapping the same region */
>>
>> If I understand the comment correctly, we can now revert commit
>> 8294a64d7f9 and and remove the alias, isn't it?
> 
> Yes, even inline vga_init_vbe and remove vbe_mapped.

Sounds like a good idea!

> ----------------- 8< ----------------
> From: Paolo Bonzini <pbonzini@redhat.com>
> Subject: [PATCH] vga: cleanup mapping of VRAM for non-PCI VGA
> 
> vga_init_vbe is now used only from ISA VGA cards.  Since the alias is
> not needed anymore, remove it (effectively reverting commit 8294a64d7f,
> "vga: fix vram double-mapping with -vga std and -M pc-0.12", 2012-05-29)
> and the new unused vbe_mapped field of VGACommonState.  The function now
> consists of a single memory_region_add_subregion call, so we can inline
> it and avoid incorrect usage from PCI cards.
> 
> Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> diff --git a/hw/display/vga-isa-mm.c b/hw/display/vga-isa-mm.c
> index e9c43e5530..06f93c4ef5 100644
> --- a/hw/display/vga-isa-mm.c
> +++ b/hw/display/vga-isa-mm.c
> @@ -106,6 +106,9 @@ int isa_vga_mm_init(hwaddr vram_base,
>  
>      s->vga.con = graphic_console_init(NULL, 0, s->vga.hw_ops, s);
>  
> -    vga_init_vbe(&s->vga, NULL, address_space);
> +    memory_region_add_subregion(system_memory,

Use address_space instead of system_memory ?

> +                                VBE_DISPI_LFB_PHYSICAL_ADDRESS,
> +                                &s->vram);
> +
>      return 0;
>  }
> diff --git a/hw/display/vga-isa.c b/hw/display/vga-isa.c
> index 873e5e9706..5b0b567835 100644
> --- a/hw/display/vga-isa.c
> +++ b/hw/display/vga-isa.c
> @@ -76,7 +76,9 @@ static void vga_isa_realizefn(DeviceState *dev, Error **errp)
>      memory_region_set_coalescing(vga_io_memory);
>      s->con = graphic_console_init(DEVICE(dev), 0, s->hw_ops, s);
>  
> -    vga_init_vbe(s, OBJECT(dev), isa_address_space(isadev));
> +    memory_region_add_subregion(system_memory,

isa_address_space(isadev) instead of system_memory ?

> +                                VBE_DISPI_LFB_PHYSICAL_ADDRESS,
> +                                &s->vram);
>      /* ROM BIOS */
>      rom_add_vga(VGABIOS_FILENAME);
>  }
> diff --git a/hw/display/vga.c b/hw/display/vga.c
> index 636586a476..061fd9ab8f 100644
> --- a/hw/display/vga.c
> +++ b/hw/display/vga.c
> @@ -2301,15 +2301,3 @@ void vga_init(VGACommonState *s, Object *obj, MemoryRegion *address_space,
>          portio_list_add(&s->vbe_port_list, address_space_io, 0x1ce);
>      }
>  }
> -
> -void vga_init_vbe(VGACommonState *s, Object *obj, MemoryRegion *system_memory)
> -{
> -    /* Use an alias to avoid double-mapping the same region */
> -    memory_region_init_alias(&s->vram_vbe, obj, "vram.vbe",
> -                             &s->vram, 0, memory_region_size(&s->vram));
> -    /* XXX: use optimized standard vga accesses */
> -    memory_region_add_subregion(system_memory,
> -                                VBE_DISPI_LFB_PHYSICAL_ADDRESS,
> -                                &s->vram_vbe);
> -    s->vbe_mapped = 1;
> -}
> diff --git a/hw/display/vga_int.h b/hw/display/vga_int.h
> index 55c418eab5..3081be445d 100644
> --- a/hw/display/vga_int.h
> +++ b/hw/display/vga_int.h
> @@ -106,7 +106,6 @@ typedef struct VGACommonState {
>      uint32_t vbe_start_addr;
>      uint32_t vbe_line_offset;
>      uint32_t vbe_bank_mask;
> -    int vbe_mapped;
I think you can now also remove "vram_vbe" from this file.

 Thomas