diff mbox series

[v3,6/6] hw/i386/pc_sysfw: Alias rather than copy isa-bios region

Message ID 20240508175507.22270-7-shentey@gmail.com
State New
Headers show
Series X86: Alias isa-bios area and clean up | expand

Commit Message

Bernhard Beschow May 8, 2024, 5:55 p.m. UTC 
In the -bios case the "isa-bios" memory region is an alias to the BIOS mapped
to the top of the 4G memory boundary. Do the same in the -pflash case, but only
for new machine versions for migration compatibility. This establishes common
behavior and makes pflash commands work in the "isa-bios" region which some
real-world legacy bioses rely on.

Note that in the sev_enabled() case, the "isa-bios" memory region in the -pflash
case will now also point to encrypted memory, just like it already does in the
-bios case.

When running `info mtree` before and after this commit with
`qemu-system-x86_64 -S -drive \
if=pflash,format=raw,readonly=on,file=/usr/share/qemu/bios-256k.bin` and running
`diff -u before.mtree after.mtree` results in the following changes in the
memory tree:

   --- before.mtree
   +++ after.mtree
   @@ -71,7 +71,7 @@
        0000000000000000-ffffffffffffffff (prio -1, i/o): pci
        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
        00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
   -      00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
   +      00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
        00000000000a0000-00000000000bffff (prio 1, i/o): alias smram-region @pci 00000000000a0000-00000000000bffff
        00000000000c0000-00000000000c3fff (prio 1, i/o): alias pam-pci @pci 00000000000c0000-00000000000c3fff
        00000000000c4000-00000000000c7fff (prio 1, i/o): alias pam-pci @pci 00000000000c4000-00000000000c7fff
   @@ -108,7 +108,7 @@
        0000000000000000-ffffffffffffffff (prio -1, i/o): pci
        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
        00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
   -      00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
   +      00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
        00000000000a0000-00000000000bffff (prio 1, i/o): alias smram-region @pci 00000000000a0000-00000000000bffff
        00000000000c0000-00000000000c3fff (prio 1, i/o): alias pam-pci @pci 00000000000c0000-00000000000c3fff
        00000000000c4000-00000000000c7fff (prio 1, i/o): alias pam-pci @pci 00000000000c4000-00000000000c7fff
   @@ -131,11 +131,14 @@
   memory-region: pc.ram
   0000000000000000-0000000007ffffff (prio 0, ram): pc.ram

   +memory-region: system.flash0
   +  00000000fffc0000-00000000ffffffff (prio 0, romd): system.flash0
   +
   memory-region: pci
   0000000000000000-ffffffffffffffff (prio -1, i/o): pci
        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
        00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
   -    00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
   +    00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff

   memory-region: smram
        00000000000a0000-00000000000bffff (prio 0, ram): alias smram-low @pc.ram 00000000000a0000-00000000000bffff

Note that in both cases the "system" memory region contains the entry

  00000000fffc0000-00000000ffffffff (prio 0, romd): system.flash0

but the "system.flash0" memory region only appears standalone when "isa-bios" is
an alias.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 include/hw/i386/pc.h | 1 +
 hw/i386/pc.c         | 1 +
 hw/i386/pc_piix.c    | 3 +++
 hw/i386/pc_q35.c     | 2 ++
 hw/i386/pc_sysfw.c   | 8 +++++++-
 5 files changed, 14 insertions(+), 1 deletion(-)

Comments

Bernhard Beschow May 21, 2024, 7:10 a.m. UTC | #1 
Am 8. Mai 2024 17:55:07 UTC schrieb Bernhard Beschow <shentey@gmail.com>:
>In the -bios case the "isa-bios" memory region is an alias to the BIOS mapped
>to the top of the 4G memory boundary. Do the same in the -pflash case, but only
>for new machine versions for migration compatibility. This establishes common
>behavior and makes pflash commands work in the "isa-bios" region which some
>real-world legacy bioses rely on.
>
>Note that in the sev_enabled() case, the "isa-bios" memory region in the -pflash
>case will now also point to encrypted memory, just like it already does in the
>-bios case.
>
>When running `info mtree` before and after this commit with
>`qemu-system-x86_64 -S -drive \
>if=pflash,format=raw,readonly=on,file=/usr/share/qemu/bios-256k.bin` and running
>`diff -u before.mtree after.mtree` results in the following changes in the
>memory tree:
>
>   --- before.mtree
>   +++ after.mtree
>   @@ -71,7 +71,7 @@
>        0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
>        00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
>   -      00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
>   +      00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
>        00000000000a0000-00000000000bffff (prio 1, i/o): alias smram-region @pci 00000000000a0000-00000000000bffff
>        00000000000c0000-00000000000c3fff (prio 1, i/o): alias pam-pci @pci 00000000000c0000-00000000000c3fff
>        00000000000c4000-00000000000c7fff (prio 1, i/o): alias pam-pci @pci 00000000000c4000-00000000000c7fff
>   @@ -108,7 +108,7 @@
>        0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
>        00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
>   -      00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
>   +      00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
>        00000000000a0000-00000000000bffff (prio 1, i/o): alias smram-region @pci 00000000000a0000-00000000000bffff
>        00000000000c0000-00000000000c3fff (prio 1, i/o): alias pam-pci @pci 00000000000c0000-00000000000c3fff
>        00000000000c4000-00000000000c7fff (prio 1, i/o): alias pam-pci @pci 00000000000c4000-00000000000c7fff
>   @@ -131,11 +131,14 @@
>   memory-region: pc.ram
>   0000000000000000-0000000007ffffff (prio 0, ram): pc.ram
>
>   +memory-region: system.flash0
>   +  00000000fffc0000-00000000ffffffff (prio 0, romd): system.flash0
>   +
>   memory-region: pci
>   0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
>        00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
>   -    00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
>   +    00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
>
>   memory-region: smram
>        00000000000a0000-00000000000bffff (prio 0, ram): alias smram-low @pc.ram 00000000000a0000-00000000000bffff
>
>Note that in both cases the "system" memory region contains the entry
>
>  00000000fffc0000-00000000ffffffff (prio 0, romd): system.flash0
>
>but the "system.flash0" memory region only appears standalone when "isa-bios" is
>an alias.
>
>Signed-off-by: Bernhard Beschow <shentey@gmail.com>

Ping

This is the only patch in this series which hasn't got an R-b tag yet (the others are already in master) and I'm not aware of any open issues.

Best regards,
Bernhard
Paolo Bonzini May 21, 2024, 7:13 a.m. UTC | #2 
Il mar 21 mag 2024, 09:10 Bernhard Beschow <shentey@gmail.com> ha scritto:

> This is the only patch in this series which hasn't got an R-b tag yet (the
> others are already in master) and I'm not aware of any open issues.
>

I will queue it then.

Paolo


> Best regards,
> Bernhard
>
>
Michael S. Tsirkin May 21, 2024, 7:42 a.m. UTC | #3 
On Wed, May 08, 2024 at 07:55:07PM +0200, Bernhard Beschow wrote:
> In the -bios case the "isa-bios" memory region is an alias to the BIOS mapped
> to the top of the 4G memory boundary. Do the same in the -pflash case, but only
> for new machine versions for migration compatibility. This establishes common
> behavior and makes pflash commands work in the "isa-bios" region which some
> real-world legacy bioses rely on.
> 
> Note that in the sev_enabled() case, the "isa-bios" memory region in the -pflash
> case will now also point to encrypted memory, just like it already does in the
> -bios case.
> 
> When running `info mtree` before and after this commit with
> `qemu-system-x86_64 -S -drive \
> if=pflash,format=raw,readonly=on,file=/usr/share/qemu/bios-256k.bin` and running
> `diff -u before.mtree after.mtree` results in the following changes in the
> memory tree:
> 
>    --- before.mtree
>    +++ after.mtree
>    @@ -71,7 +71,7 @@
>         0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>         00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
>         00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
>    -      00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
>    +      00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
>         00000000000a0000-00000000000bffff (prio 1, i/o): alias smram-region @pci 00000000000a0000-00000000000bffff
>         00000000000c0000-00000000000c3fff (prio 1, i/o): alias pam-pci @pci 00000000000c0000-00000000000c3fff
>         00000000000c4000-00000000000c7fff (prio 1, i/o): alias pam-pci @pci 00000000000c4000-00000000000c7fff
>    @@ -108,7 +108,7 @@
>         0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>         00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
>         00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
>    -      00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
>    +      00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
>         00000000000a0000-00000000000bffff (prio 1, i/o): alias smram-region @pci 00000000000a0000-00000000000bffff
>         00000000000c0000-00000000000c3fff (prio 1, i/o): alias pam-pci @pci 00000000000c0000-00000000000c3fff
>         00000000000c4000-00000000000c7fff (prio 1, i/o): alias pam-pci @pci 00000000000c4000-00000000000c7fff
>    @@ -131,11 +131,14 @@
>    memory-region: pc.ram
>    0000000000000000-0000000007ffffff (prio 0, ram): pc.ram
> 
>    +memory-region: system.flash0
>    +  00000000fffc0000-00000000ffffffff (prio 0, romd): system.flash0
>    +
>    memory-region: pci
>    0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>         00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
>         00000000000c0000-00000000000dffff (prio 1, rom): pc.rom
>    -    00000000000e0000-00000000000fffff (prio 1, rom): isa-bios
>    +    00000000000e0000-00000000000fffff (prio 1, romd): alias isa-bios @system.flash0 0000000000020000-000000000003ffff
> 
>    memory-region: smram
>         00000000000a0000-00000000000bffff (prio 0, ram): alias smram-low @pc.ram 00000000000a0000-00000000000bffff
> 
> Note that in both cases the "system" memory region contains the entry
> 
>   00000000fffc0000-00000000ffffffff (prio 0, romd): system.flash0
> 
> but the "system.flash0" memory region only appears standalone when "isa-bios" is
> an alias.
> 
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

feel free to queue

> ---
>  include/hw/i386/pc.h | 1 +
>  hw/i386/pc.c         | 1 +
>  hw/i386/pc_piix.c    | 3 +++
>  hw/i386/pc_q35.c     | 2 ++
>  hw/i386/pc_sysfw.c   | 8 +++++++-
>  5 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index e52290916c..ad9c3d9ba8 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -119,6 +119,7 @@ struct PCMachineClass {
>      bool enforce_aligned_dimm;
>      bool broken_reserved_end;
>      bool enforce_amd_1tb_hole;
> +    bool isa_bios_alias;
>  
>      /* generate legacy CPU hotplug AML */
>      bool legacy_cpu_hotplug;
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 46235466d7..4878705af7 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1812,6 +1812,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
>      pcmc->has_reserved_memory = true;
>      pcmc->enforce_aligned_dimm = true;
>      pcmc->enforce_amd_1tb_hole = true;
> +    pcmc->isa_bios_alias = true;
>      /* BIOS ACPI tables: 128K. Other BIOS datastructures: less than 4K reported
>       * to be used at the moment, 32K should be enough for a while.  */
>      pcmc->acpi_data_size = 0x20000 + 0x8000;
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 8850c49c66..d4e9deb509 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -525,12 +525,15 @@ DEFINE_I440FX_MACHINE(v9_1, "pc-i440fx-9.1", NULL,
>  
>  static void pc_i440fx_9_0_machine_options(MachineClass *m)
>  {
> +    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_9_1_machine_options(m);
>      m->alias = NULL;
>      m->is_default = false;
>  
>      compat_props_add(m->compat_props, hw_compat_9_0, hw_compat_9_0_len);
>      compat_props_add(m->compat_props, pc_compat_9_0, pc_compat_9_0_len);
> +    pcmc->isa_bios_alias = false;
>  }
>  
>  DEFINE_I440FX_MACHINE(v9_0, "pc-i440fx-9.0", NULL,
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index bb53a51ac1..bd7db4abac 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -378,10 +378,12 @@ DEFINE_Q35_MACHINE(v9_1, "pc-q35-9.1", NULL,
>  
>  static void pc_q35_9_0_machine_options(MachineClass *m)
>  {
> +    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pc_q35_9_1_machine_options(m);
>      m->alias = NULL;
>      compat_props_add(m->compat_props, hw_compat_9_0, hw_compat_9_0_len);
>      compat_props_add(m->compat_props, pc_compat_9_0, pc_compat_9_0_len);
> +    pcmc->isa_bios_alias = false;
>  }
>  
>  DEFINE_Q35_MACHINE(v9_0, "pc-q35-9.0", NULL,
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index 82d37cb376..ac88ad4eb9 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -135,6 +135,7 @@ static void pc_system_flash_map(PCMachineState *pcms,
>                                  MemoryRegion *rom_memory)
>  {
>      X86MachineState *x86ms = X86_MACHINE(pcms);
> +    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
>      hwaddr total_size = 0;
>      int i;
>      BlockBackend *blk;
> @@ -184,7 +185,12 @@ static void pc_system_flash_map(PCMachineState *pcms,
>  
>          if (i == 0) {
>              flash_mem = pflash_cfi01_get_memory(system_flash);
> -            pc_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem);
> +            if (pcmc->isa_bios_alias) {
> +                x86_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem,
> +                                  true);
> +            } else {
> +                pc_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem);
> +            }
>  
>              /* Encrypt the pflash boot ROM */
>              if (sev_enabled()) {
> -- 
> 2.45.0
diff mbox series

Patch

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index e52290916c..ad9c3d9ba8 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -119,6 +119,7 @@  struct PCMachineClass {
     bool enforce_aligned_dimm;
     bool broken_reserved_end;
     bool enforce_amd_1tb_hole;
+    bool isa_bios_alias;
 
     /* generate legacy CPU hotplug AML */
     bool legacy_cpu_hotplug;
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 46235466d7..4878705af7 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1812,6 +1812,7 @@  static void pc_machine_class_init(ObjectClass *oc, void *data)
     pcmc->has_reserved_memory = true;
     pcmc->enforce_aligned_dimm = true;
     pcmc->enforce_amd_1tb_hole = true;
+    pcmc->isa_bios_alias = true;
     /* BIOS ACPI tables: 128K. Other BIOS datastructures: less than 4K reported
      * to be used at the moment, 32K should be enough for a while.  */
     pcmc->acpi_data_size = 0x20000 + 0x8000;
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 8850c49c66..d4e9deb509 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -525,12 +525,15 @@  DEFINE_I440FX_MACHINE(v9_1, "pc-i440fx-9.1", NULL,
 
 static void pc_i440fx_9_0_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
+
     pc_i440fx_9_1_machine_options(m);
     m->alias = NULL;
     m->is_default = false;
 
     compat_props_add(m->compat_props, hw_compat_9_0, hw_compat_9_0_len);
     compat_props_add(m->compat_props, pc_compat_9_0, pc_compat_9_0_len);
+    pcmc->isa_bios_alias = false;
 }
 
 DEFINE_I440FX_MACHINE(v9_0, "pc-i440fx-9.0", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index bb53a51ac1..bd7db4abac 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -378,10 +378,12 @@  DEFINE_Q35_MACHINE(v9_1, "pc-q35-9.1", NULL,
 
 static void pc_q35_9_0_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_9_1_machine_options(m);
     m->alias = NULL;
     compat_props_add(m->compat_props, hw_compat_9_0, hw_compat_9_0_len);
     compat_props_add(m->compat_props, pc_compat_9_0, pc_compat_9_0_len);
+    pcmc->isa_bios_alias = false;
 }
 
 DEFINE_Q35_MACHINE(v9_0, "pc-q35-9.0", NULL,
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index 82d37cb376..ac88ad4eb9 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -135,6 +135,7 @@  static void pc_system_flash_map(PCMachineState *pcms,
                                 MemoryRegion *rom_memory)
 {
     X86MachineState *x86ms = X86_MACHINE(pcms);
+    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
     hwaddr total_size = 0;
     int i;
     BlockBackend *blk;
@@ -184,7 +185,12 @@  static void pc_system_flash_map(PCMachineState *pcms,
 
         if (i == 0) {
             flash_mem = pflash_cfi01_get_memory(system_flash);
-            pc_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem);
+            if (pcmc->isa_bios_alias) {
+                x86_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem,
+                                  true);
+            } else {
+                pc_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem);
+            }
 
             /* Encrypt the pflash boot ROM */
             if (sev_enabled()) {