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

[Paolo Bonzini <pbonzini@redhat.com>]

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.

----------------- 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,
+                                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,
+                                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;
     /* display refresh support */
     QemuConsole *con;
     uint32_t font_offsets[2];
@@ -178,7 +177,6 @@ void vga_invalidate_scanlines(VGACommonState *s, int y1, int y2);
 
 int vga_ioport_invalid(VGACommonState *s, uint32_t addr);
 
-void vga_init_vbe(VGACommonState *s, Object *obj, MemoryRegion *address_space);
 uint32_t vbe_ioport_read_data(void *opaque, uint32_t addr);
 void vbe_ioport_write_index(void *opaque, uint32_t addr, uint32_t val);
 void vbe_ioport_write_data(void *opaque, uint32_t addr, uint32_t val);