[PATCH] RFC: Use CONFIG_HAS_IOPORT around vcpu->pio_data

[PATCH] RFC: Use CONFIG_HAS_IOPORT around vcpu->pio_data

[Hollis Blanchard]

Signed-off-by: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
pio_data is obviously arch-specific, but we might be able to get by with an
ifdef in kvm_vcpu_nopage() rather than needing an arch hook. Thoughts?

1 file changed, 2 insertions(+)
drivers/kvm/kvm_main.c |    2 ++


diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -674,8 +674,10 @@ static struct page *kvm_vcpu_nopage(stru
 	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
 	if (pgoff == 0)
 		page = virt_to_page(vcpu->run);
+#ifdef CONFIG_HAS_IOPORT
 	else if (pgoff == KVM_PIO_PAGE_OFFSET)
 		page = virt_to_page(vcpu->pio_data);
+#endif /* CONFIG_HAS_IOPORT */
 	else
 		return NOPAGE_SIGBUS;
 	get_page(page);

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Re: [PATCH] RFC: Use CONFIG_HAS_IOPORT around vcpu->pio_data

[Hollis Blanchard]

Actually, (now that I try to build with it :) this doesn't work for
PowerPC, which defines (or rather, doesn't not define)
CONFIG_HAS_IOPORT.

So I guess a callout to arch code will do. I'll send a patch sometime.

-- 
Hollis Blanchard
IBM Linux Technology Center

On Mon, 2007-12-03 at 16:14 -0600, Hollis Blanchard wrote:
> Signed-off-by: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> ---
> pio_data is obviously arch-specific, but we might be able to get by with an
> ifdef in kvm_vcpu_nopage() rather than needing an arch hook. Thoughts?
> 
> 1 file changed, 2 insertions(+)
> drivers/kvm/kvm_main.c |    2 ++
> 
> 
> diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
> --- a/drivers/kvm/kvm_main.c
> +++ b/drivers/kvm/kvm_main.c
> @@ -674,8 +674,10 @@ static struct page *kvm_vcpu_nopage(stru
>  	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
>  	if (pgoff == 0)
>  		page = virt_to_page(vcpu->run);
> +#ifdef CONFIG_HAS_IOPORT
>  	else if (pgoff == KVM_PIO_PAGE_OFFSET)
>  		page = virt_to_page(vcpu->pio_data);
> +#endif /* CONFIG_HAS_IOPORT */
>  	else
>  		return NOPAGE_SIGBUS;
>  	get_page(page);
> 
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Re: [kvm-ppc-devel] [PATCH] RFC: Use CONFIG_HAS_IOPORTaround vcpu->pio_data

[Zhang, Xiantao]

Hollis Blanchard wrote:
> Actually, (now that I try to build with it :) this doesn't work for
> PowerPC, which defines (or rather, doesn't not define)
> CONFIG_HAS_IOPORT.

You mean ppc has ioport , but you don't use current kvm io
infrastructure to handle it ? 
Xiantao


> On Mon, 2007-12-03 at 16:14 -0600, Hollis Blanchard wrote:
>> Signed-off-by: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> ---
>> pio_data is obviously arch-specific, but we might be able to get by
>> with an ifdef in kvm_vcpu_nopage() rather than needing an arch hook.
>> Thoughts? 
>> 
>> 1 file changed, 2 insertions(+)
>> drivers/kvm/kvm_main.c |    2 ++
>> 
>> 
>> diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c ---
>> a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c
>> @@ -674,8 +674,10 @@ static struct page *kvm_vcpu_nopage(stru
>>  	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff;
>>  		if (pgoff == 0) page = virt_to_page(vcpu->run);
>> +#ifdef CONFIG_HAS_IOPORT
>>  	else if (pgoff == KVM_PIO_PAGE_OFFSET)
>>  		page = virt_to_page(vcpu->pio_data);
>> +#endif /* CONFIG_HAS_IOPORT */
>>  	else
>>  		return NOPAGE_SIGBUS;
>>  	get_page(page);
>> 
>>
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>> https://lists.sourceforge.net/lists/listinfo/kvm-devel
> 
> 
>
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Re: [kvm-ppc-devel] [PATCH] RFC: Use CONFIG_HAS_IOPORTaround vcpu->pio_data

[Hollis Blanchard]

On Tue, 2007-12-04 at 12:39 +0800, Zhang, Xiantao wrote:
> Hollis Blanchard wrote:
> > Actually, (now that I try to build with it :) this doesn't work for
> > PowerPC, which defines (or rather, doesn't not define)
> > CONFIG_HAS_IOPORT.
> 
> You mean ppc has ioport , but you don't use current kvm io
> infrastructure to handle it ? 

It's a matter of perspective. :)

The PowerPC architecture has no "IO" instructions; therefore all IO
accesses are MMIO.

However, you can place devices with IO ports in a PowerPC system. In
this case, the bridges are configured to translate MMIO accesses coming
from the processor into IO port accesses on the bus. It is quite common
to find standard x86 ISA devices, such as a SuperIO chip, in PowerPC
systems.

In Linux, CONFIG_HAS_IOPORT doesn't really mean "does the architecture
use IO ports," which is what I thought it meant. Instead, it means
"should we track IO resources as well as MMIO resources," and that's
true on PowerPC because we need manage the ISA bus as mentioned above.
(The only current user of the symbol is lib/devres.c.)

In summary, it's an inappropriate ifdef for this situation.

-- 
Hollis Blanchard
IBM Linux Technology Center


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Re: [kvm-ppc-devel] [PATCH] RFC: UseCONFIG_HAS_IOPORTaround vcpu->pio_data

[Zhang, Xiantao]

Hollis Blanchard wrote:
> On Tue, 2007-12-04 at 12:39 +0800, Zhang, Xiantao wrote:
>> Hollis Blanchard wrote:
>>> Actually, (now that I try to build with it :) this doesn't work for
>>> PowerPC, which defines (or rather, doesn't not define)
>>> CONFIG_HAS_IOPORT.
>> 
>> You mean ppc has ioport , but you don't use current kvm io
>> infrastructure to handle it ?
> 
> It's a matter of perspective. :)
> 
> The PowerPC architecture has no "IO" instructions; therefore all IO
> accesses are MMIO.
> However, you can place devices with IO ports in a PowerPC system. In
> this case, the bridges are configured to translate MMIO accesses
> coming from the processor into IO port accesses on the bus. It is
> quite common to find standard x86 ISA devices, such as a SuperIO

Thank you for your elaboration. 
So, bridge emulation in qemu will take over the responsibility of the
translation for ppc? 

> In Linux, CONFIG_HAS_IOPORT doesn't really mean "does the architecture
> use IO ports," which is what I thought it meant. Instead, it means
> "should we track IO resources as well as MMIO resources," and that's
> true on PowerPC because we need manage the ISA bus as mentioned above.
> (The only current user of the symbol is lib/devres.c.)
> 
> In summary, it's an inappropriate ifdef for this situation.

Agree. 

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Re: [kvm-ppc-devel] [PATCH] RFC: UseCONFIG_HAS_IOPORTaround vcpu->pio_data

[Hollis Blanchard]

On Tue, 2007-12-04 at 13:04 +0800, Zhang, Xiantao wrote:
> 
> Hollis Blanchard wrote:
> > On Tue, 2007-12-04 at 12:39 +0800, Zhang, Xiantao wrote:
> >> Hollis Blanchard wrote:
> >>> Actually, (now that I try to build with it :) this doesn't work
> for
> >>> PowerPC, which defines (or rather, doesn't not define)
> >>> CONFIG_HAS_IOPORT.
> >> 
> >> You mean ppc has ioport , but you don't use current kvm io
> >> infrastructure to handle it ?
> > 
> > It's a matter of perspective. :)
> > 
> > The PowerPC architecture has no "IO" instructions; therefore all IO
> > accesses are MMIO.
> > However, you can place devices with IO ports in a PowerPC system. In
> > this case, the bridges are configured to translate MMIO accesses
> > coming from the processor into IO port accesses on the bus. It is
> > quite common to find standard x86 ISA devices, such as a SuperIO
> 
> Thank you for your elaboration. 
> So, bridge emulation in qemu will take over the responsibility of the
> translation for ppc? 

Yup.

-- 
Hollis Blanchard
IBM Linux Technology Center


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Re: [kvm-ppc-devel] [PATCH] RFC:Use CONFIG_HAS_IOPORTaround vcpu->pio_data

[Dong, Eddie]

>It's a matter of perspective. :)
>
>The PowerPC architecture has no "IO" instructions; therefore all IO
>accesses are MMIO.
>
>However, you can place devices with IO ports in a PowerPC system. In
>this case, the bridges are configured to translate MMIO accesses coming
>from the processor into IO port accesses on the bus. It is quite common
>to find standard x86 ISA devices, such as a SuperIO chip, in PowerPC
>systems.
>
That is exactly what IA64 architecture takes.
I guess PIO is X86 historic issue when there as only 16 bits bus 20
years ago.
And it is probably due to 8085 which is for embedded system. 
All other archs may support PIO due to plenty of X86 devices, but do
emulating PIO
in chipset/bridge like PPC/IA64.

Of course except S390 which is really different and doesn't want to take
"open" devices:(

Eddie.

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Re: [PATCH] RFC: Use CONFIG_HAS_IOPORT around vcpu->pio_data

[Avi Kivity]

Hollis Blanchard wrote:
> Actually, (now that I try to build with it :) this doesn't work for
> PowerPC, which defines (or rather, doesn't not define)
> CONFIG_HAS_IOPORT.
>
> So I guess a callout to arch code will do. I'll send a patch sometime.
>
>   

We can also have a CONFIG_KVM_HAS_PIO and define/not define it as 
appropriate.

-- 
error compiling committee.c: too many arguments to function


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