Xen devel - Jan 2012 - [PATCH] xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callback

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 492ade8..d99346e 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -374,7 +374,7 @@ int __init pci_xen_init(void)
 
 int __init pci_xen_hvm_init(void)
 {
-	if (!xen_feature(XENFEAT_hvm_pirqs))
+	if (!xen_have_vector_callback || !xen_feature(XENFEAT_hvm_pirqs))
 		return 0;
 
 #ifdef CONFIG_ACPI

On Mon, Jan 30, 2012 at 02:31:46PM +0000, Stefano Stabellini
wrote:
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
So the xen_have_vector_callback looks to be only set by

1398         if (xen_feature(XENFEAT_hvm_callback_vector))
1399                 xen_have_vector_callback = 1;

So could this be just done via a check for that instead?

> 
> diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
> index 492ade8..d99346e 100644
> --- a/arch/x86/pci/xen.c
> +++ b/arch/x86/pci/xen.c
> @@ -374,7 +374,7 @@ int __init pci_xen_init(void)
>  
>  int __init pci_xen_hvm_init(void)
>  {
> -	if (!xen_feature(XENFEAT_hvm_pirqs))
> +	if (!xen_have_vector_callback || !xen_feature(XENFEAT_hvm_pirqs))
>  		return 0;
>  
>  #ifdef CONFIG_ACPI
> --
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On Tue, 31 Jan 2012, Konrad Rzeszutek Wilk wrote:
> On Mon, Jan 30, 2012 at 02:31:46PM +0000, Stefano Stabellini wrote:
> > 
> > Signed-off-by: Stefano Stabellini
<stefano.stabellini@eu.citrix.com>
> 
> So the xen_have_vector_callback looks to be only set by
> 
> 1398         if (xen_feature(XENFEAT_hvm_callback_vector))
> 1399                 xen_have_vector_callback = 1;
> 
> So could this be just done via a check for that instead?
> 
Sure, but I don''t think it would be better: using
xen_have_vector_callback is more consistent and give us the flexibility
of allowing users to manually override it in the future.

On Tue, Jan 31, 2012 at 04:40:26PM +0000, Stefano Stabellini
wrote:
> On Tue, 31 Jan 2012, Konrad Rzeszutek Wilk wrote:
> > On Mon, Jan 30, 2012 at 02:31:46PM +0000, Stefano Stabellini wrote:
> > > 
> > > Signed-off-by: Stefano Stabellini
<stefano.stabellini@eu.citrix.com>
> > 
> > So the xen_have_vector_callback looks to be only set by
> > 
> > 1398         if (xen_feature(XENFEAT_hvm_callback_vector))
> > 1399                 xen_have_vector_callback = 1;
> > 
> > So could this be just done via a check for that instead?
> > 
> 
> Sure, but I don''t think it would be better: using
> xen_have_vector_callback is more consistent and give us the flexibility
> of allowing users to manually override it in the future.
ok. applied. Hm, I was thinking to put on stable@kernel.org - but how
far back should it go? 2.6.37?
> 
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> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

On Wed, 1 Feb 2012, Konrad Rzeszutek Wilk wrote:
> On Tue, Jan 31, 2012 at 04:40:26PM +0000, Stefano Stabellini wrote:
> > On Tue, 31 Jan 2012, Konrad Rzeszutek Wilk wrote:
> > > On Mon, Jan 30, 2012 at 02:31:46PM +0000, Stefano Stabellini
wrote:
> > > > 
> > > > Signed-off-by: Stefano Stabellini
<stefano.stabellini@eu.citrix.com>
> > > 
> > > So the xen_have_vector_callback looks to be only set by
> > > 
> > > 1398         if (xen_feature(XENFEAT_hvm_callback_vector))
> > > 1399                 xen_have_vector_callback = 1;
> > > 
> > > So could this be just done via a check for that instead?
> > > 
> > 
> > Sure, but I don''t think it would be better: using
> > xen_have_vector_callback is more consistent and give us the
flexibility
> > of allowing users to manually override it in the future.
> 
> ok. applied. Hm, I was thinking to put on stable@kernel.org - but how
> far back should it go? 2.6.37?
Yes, I think is 2.6.37 when we introduced using XENFEAT_hvm_pirqs.