[Patch] [BIOS] support BCV for rombios

[Patch] [BIOS] support BCV for rombios

[Akio Takebe]

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Hi,

This patch supports BCV for PCI device.
If we use this patch in Xen, we would need some more fixes.
This patch just support BCV.
We could boot a full virtualize guest from a Pass through device
with VT-d on Xen.

Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com>
Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>

Ref:
- XenSummit Asia 2008
  http://www.xen.org/files/xensummit_tokyo/24_Hitoshi%20Matsumoto_en.pdf
- BIOS Boot Specification
  http://www.phoenix.com/NR/rdonlyres/56E38DE2-3E6F-4743-835F-B4A53726ABED/0/specsbbs101.pdf

Best Regards,

Akio Takebe

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Index: rombios.c
===================================================================
RCS file: /cvsroot/bochs/bochs/bios/rombios.c,v
retrieving revision 1.209
diff -c -r1.209 rombios.c
*** rombios.c	2 Jun 2008 20:08:10 -0000	1.209
--- rombios.c	8 Dec 2008 10:09:53 -0000
***************
*** 10194,10199 ****
--- 10194,10223 ----
    mov  ax, 2[bx]
    cmp  ax, #0x506e
    jne  no_bev
+ 
+   mov  ax, 0x16[bx] ;; 0x16 is the offset of Boot Connection Vector
+   cmp  ax, #0x0000
+   je   no_bcv
+ 
+   ;; Option ROM has BCV. Run it now.
+   push cx       ;; Push seg
+   push ax       ;; Push offset
+ 
+   ;; Point ES:DI at "$PnP", which tells the ROM that we are a PnP BIOS.
+   mov  bx, #0xf000
+   mov  es, bx
+   lea  di, pnp_string
+   /* jump to BCV function entry pointer */
+   mov  bp, sp   ;; Call ROM BCV routine using seg:off on stack
+   db   0xff     ;; call_far ss:[bp+0]
+   db   0x5e
+   db   0
+   cli           ;; In case expansion ROM BIOS turns IF on
+   add  sp, #2   ;; Pop offset value
+   pop  cx       ;; Pop seg value (restore CX)
+   ja   no_bev
+ 
+ no_bcv:
    mov  ax, 0x1a[bx] ;; 0x1A is also the offset into the expansion header of...
    cmp  ax, #0x0000  ;; the Bootstrap Entry Vector, or zero if there is none.
    je   no_bev

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Re: [Patch] [BIOS] support BCV for rombios

[Sebastian Herbszt]

Akio Takebe wrote:
> Hi,
> 
> This patch supports BCV for PCI device.
> If we use this patch in Xen, we would need some more fixes.
> This patch just support BCV.
> We could boot a full virtualize guest from a Pass through device
> with VT-d on Xen.
> 
> Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com>
> Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>
> 
> Ref:
> - XenSummit Asia 2008
>  http://www.xen.org/files/xensummit_tokyo/24_Hitoshi%20Matsumoto_en.pdf
> - BIOS Boot Specification
>  http://www.phoenix.com/NR/rdonlyres/56E38DE2-3E6F-4743-835F-B4A53726ABED/0/specsbbs101.pdf
> 
> Best Regards,
> 
> Akio Takebe
> 
> Index: rombios.c
> ===================================================================
> RCS file: /cvsroot/bochs/bochs/bios/rombios.c,v
> retrieving revision 1.209
> diff -c -r1.209 rombios.c
> *** rombios.c 2 Jun 2008 20:08:10 -0000 1.209
> --- rombios.c 8 Dec 2008 10:09:53 -0000
> ***************
> *** 10194,10199 ****
> --- 10194,10223 ----
>     mov  ax, 2[bx]
>     cmp  ax, #0x506e
>     jne  no_bev
> + 
> +   mov  ax, 0x16[bx] ;; 0x16 is the offset of Boot Connection Vector
> +   cmp  ax, #0x0000
> +   je   no_bcv
> + 
> +   ;; Option ROM has BCV. Run it now.
> +   push cx       ;; Push seg
> +   push ax       ;; Push offset
> + 
> +   ;; Point ES:DI at "$PnP", which tells the ROM that we are a PnP BIOS.
> +   mov  bx, #0xf000
> +   mov  es, bx
> +   lea  di, pnp_string

Should ax, bx and dx get set to some sane value, e.g. 0? Those are only needed
for PnP ISA devices, but some broken option rom might expect something there.

> +   /* jump to BCV function entry pointer */
> +   mov  bp, sp   ;; Call ROM BCV routine using seg:off on stack
> +   db   0xff     ;; call_far ss:[bp+0]
> +   db   0x5e
> +   db   0
> +   cli           ;; In case expansion ROM BIOS turns IF on
> +   add  sp, #2   ;; Pop offset value
> +   pop  cx       ;; Pop seg value (restore CX)
> +   ja   no_bev

ja? not jmp?

> + no_bcv:
>     mov  ax, 0x1a[bx] ;; 0x1A is also the offset into the expansion header of...
>     cmp  ax, #0x0000  ;; the Bootstrap Entry Vector, or zero if there is none.
>     je   no_bev

- Sebastian


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Re: [Patch] [BIOS] support BCV for rombios

[Michael Brown]

On Thursday 11 December 2008 00:02:40 Sebastian Herbszt wrote:
> > +   ;; Point ES:DI at "$PnP", which tells the ROM that we are a PnP BIOS.
> > +   mov  bx, #0xf000
> > +   mov  es, bx
> > +   lea  di, pnp_string
>
> Should ax, bx and dx get set to some sane value, e.g. 0? Those are only
> needed for PnP ISA devices, but some broken option rom might expect
> something there.

I haven't checked the spec, but if the parameters are meant to match the 
initialisation vector or other similar entry points (e.g. the UNDI loader 
entry point for PXE ROMs) then %ax should contain the PCI bus:dev.fn number.

Michael

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Re: [Bochs-developers] [Patch] [BIOS] support BCV for rombios

[Akio Takebe]

Hi,

Thank you for your comments.

>On Thursday 11 December 2008 00:02:40 Sebastian Herbszt wrote:
>> > +   ;; Point ES:DI at "$PnP", which tells the ROM that we are a PnP BIOS.
>> > +   mov  bx, #0xf000
>> > +   mov  es, bx
>> > +   lea  di, pnp_string
>>
>> Should ax, bx and dx get set to some sane value, e.g. 0? Those are only
>> needed for PnP ISA devices, but some broken option rom might expect
>> something there.
>
Hmm. I don't find specification in the BBS spec.
But as you said, we may need to add preserving registers.
The patch is for PCI devices.
For ISA device, we would need to check if it is a PCI or ISA device.

>I haven't checked the spec, but if the parameters are meant to match the 
>initialisation vector or other similar entry points (e.g. the UNDI loader 
>entry point for PXE ROMs) then %ax should contain the PCI bus:dev.fn number.
>
>Michael

The BBS spec says:
"Note that for PCI cards, AX will not contain the PFA. PCI devices that 
need their PFA during execution of their BCV should store the PFA passed 
earlier when their option ROM’s initialization vector was called."

Best Regards,

Akio Takebe

Re: [Bochs-developers] [Patch] [BIOS] support BCV for rombios

[Akio Takebe]

Hi,

>> +   /* jump to BCV function entry pointer */
>> +   mov  bp, sp   ;; Call ROM BCV routine using seg:off on stack
>> +   db   0xff     ;; call_far ss:[bp+0]
>> +   db   0x5e
>> +   db   0
>> +   cli           ;; In case expansion ROM BIOS turns IF on
>> +   add  sp, #2   ;; Pop offset value
>> +   pop  cx       ;; Pop seg value (restore CX)
>> +   ja   no_bev
>
>ja? not jmp?
>
Oops. yes jmp.

>> + no_bcv:
>>     mov  ax, 0x1a[bx] ;; 0x1A is also the offset into the expansion header 
>> of...
>>     cmp  ax, #0x0000  ;; the Bootstrap Entry Vector, or zero if there is 
>> none.
>>     je   no_bev
>

Best Regards,

Akio Takebe

Re: [Patch] [BIOS] support BCV for rombios

[Sebastian Herbszt]

Akio Takebe wrote:
> Hi,
> 
>>> +   /* jump to BCV function entry pointer */
>>> +   mov  bp, sp   ;; Call ROM BCV routine using seg:off on stack
>>> +   db   0xff     ;; call_far ss:[bp+0]
>>> +   db   0x5e
>>> +   db   0
>>> +   cli           ;; In case expansion ROM BIOS turns IF on
>>> +   add  sp, #2   ;; Pop offset value
>>> +   pop  cx       ;; Pop seg value (restore CX)
>>> +   ja   no_bev
>>
>>ja? not jmp?
>>
> Oops. yes jmp.

Can you please resend a fixed version?

Thanks
Sebastian


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Re: [Bochs-developers] [Patch] [BIOS] support BCV for rombios

[Akio Takebe]

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Sebastian Herbszt wrote:
> Akio Takebe wrote:
>> Hi,
>>
>>>> +   /* jump to BCV function entry pointer */
>>>> +   mov  bp, sp   ;; Call ROM BCV routine using seg:off on stack
>>>> +   db   0xff     ;; call_far ss:[bp+0]
>>>> +   db   0x5e
>>>> +   db   0
>>>> +   cli           ;; In case expansion ROM BIOS turns IF on
>>>> +   add  sp, #2   ;; Pop offset value
>>>> +   pop  cx       ;; Pop seg value (restore CX)
>>>> +   ja   no_bev
>>>
>>> ja? not jmp?
>>>
>> Oops. yes jmp.
> 
> Can you please resend a fixed version?
> 
> Thanks
> Sebastian
> 
> 
Sorry, and thank you for your review. I updeted our patch.

Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com>
Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>

Best Regards,

Akio Takebe

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Index: bios/rombios.c
===================================================================
RCS file: /cvsroot/bochs/bochs/bios/rombios.c,v
retrieving revision 1.222
diff -u -r1.222 rombios.c
--- bios/rombios.c	15 Dec 2008 06:05:52 -0000	1.222
+++ bios/rombios.c	18 Dec 2008 06:15:52 -0000
@@ -10251,6 +10251,30 @@
   mov  ax, 2[bx]
   cmp  ax, #0x506e
   jne  no_bev
+
+  mov  ax, 0x16[bx] ;; 0x16 is the offset of Boot Connection Vector
+  cmp  ax, #0x0000
+  je   no_bcv
+
+  ;; Option ROM has BCV. Run it now.
+  push cx       ;; Push seg
+  push ax       ;; Push offset
+
+  ;; Point ES:DI at "$PnP", which tells the ROM that we are a PnP BIOS.
+  mov  bx, #0xf000
+  mov  es, bx
+  lea  di, pnp_string
+  /* jump to BCV function entry pointer */
+  mov  bp, sp   ;; Call ROM BCV routine using seg:off on stack
+  db   0xff     ;; call_far ss:[bp+0]
+  db   0x5e
+  db   0
+  cli           ;; In case expansion ROM BIOS turns IF on
+  add  sp, #2   ;; Pop offset value
+  pop  cx       ;; Pop seg value (restore CX)
+  jmp   no_bev
+
+no_bcv:
   mov  ax, 0x1a[bx] ;; 0x1A is also the offset into the expansion header of...
   cmp  ax, #0x0000  ;; the Bootstrap Entry Vector, or zero if there is none.
   je   no_bev

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