Patchwork [v9,10/12] x86/xen: Bypass intr mode setup in enlighten_pv system

login
register
mail settings
Submitter Dou Liyang
Date Sept. 13, 2017, 9:12 a.m.
Message ID <1505293975-26005-11-git-send-email-douly.fnst@cn.fujitsu.com>
Download mbox | patch
Permalink /patch/9950801/
State New
Headers show

Comments

Dou Liyang - Sept. 13, 2017, 9:12 a.m.
XEN PV overrides smp_prepare_cpus(). xen_pv_smp_prepare_cpus()
initializes interrupts in the XEN PV specific way and does not invoke
native_smp_prepare_cpus(). As a consequence, x86_init.intr_mode_init() is
not invoked either.

The invocation of x86_init.intr_mode_init() will be moved from
native_smp_prepare_cpus() in a follow up patch to solve <INSERT
REASON/PROBLEM>.

That move would cause the invocation of x86_init.intr_mode_init() for XEN
PV platforms. To prevent that, override the default x86_init.intr_mode_init()
callback with a noop().

[Rewrited by Thomas Gleixner <tglx@linutronix.de>]

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Cc: Juergen Gross <jgross@suse.com>
---
 arch/x86/xen/enlighten_pv.c | 1 +
 1 file changed, 1 insertion(+)
Juergen Gross - Sept. 13, 2017, 9:45 a.m.
On 13/09/17 11:12, Dou Liyang wrote:
> XEN PV overrides smp_prepare_cpus(). xen_pv_smp_prepare_cpus()
> initializes interrupts in the XEN PV specific way and does not invoke
> native_smp_prepare_cpus(). As a consequence, x86_init.intr_mode_init() is
> not invoked either.
> 
> The invocation of x86_init.intr_mode_init() will be moved from
> native_smp_prepare_cpus() in a follow up patch to solve <INSERT
> REASON/PROBLEM>.

I asked you to be more specific here before. So: what will be solved?
Can I select a problem I like? ;-)

> That move would cause the invocation of x86_init.intr_mode_init() for XEN
> PV platforms. To prevent that, override the default x86_init.intr_mode_init()
> callback with a noop().
> 
> [Rewrited by Thomas Gleixner <tglx@linutronix.de>]

Rewritten?

> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
> Cc: xen-devel@lists.xenproject.org
> Cc: boris.ostrovsky@oracle.com
> Cc: Juergen Gross <jgross@suse.com>

Regarding the changes below:

Acked-by: Juergen Gross <jgross@suse.com>


Juergen

> ---
>  arch/x86/xen/enlighten_pv.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index ae2a2e2..934dc7f 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -1232,6 +1232,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
>  	x86_platform.get_nmi_reason = xen_get_nmi_reason;
>  
>  	x86_init.resources.memory_setup = xen_memory_setup;
> +	x86_init.irqs.intr_mode_init	= x86_init_noop;
>  	x86_init.oem.arch_setup = xen_arch_setup;
>  	x86_init.oem.banner = xen_banner;
>  
>
Dou Liyang - Sept. 13, 2017, 10:09 a.m.
Hi Juergen,

At 09/13/2017 05:45 PM, Juergen Gross wrote:
> On 13/09/17 11:12, Dou Liyang wrote:
>> XEN PV overrides smp_prepare_cpus(). xen_pv_smp_prepare_cpus()
>> initializes interrupts in the XEN PV specific way and does not invoke
>> native_smp_prepare_cpus(). As a consequence, x86_init.intr_mode_init() is
>> not invoked either.
>>
>> The invocation of x86_init.intr_mode_init() will be moved from
>> native_smp_prepare_cpus() in a follow up patch to solve <INSERT
>> REASON/PROBLEM>.
>
> I asked you to be more specific here before. So: what will be solved?
> Can I select a problem I like? ;-)

Oops, I am sorry I missed it. I will modify it.

...to solve the dump-capture kernel hangs, if there is a notsc option
in its command line.

>
>> That move would cause the invocation of x86_init.intr_mode_init() for XEN
>> PV platforms. To prevent that, override the default x86_init.intr_mode_init()
>> callback with a noop().
>>
>> [Rewrited by Thomas Gleixner <tglx@linutronix.de>]
>
> Rewritten?

Yeah, yeah. poor english skill :-).

>
>> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
>> Cc: xen-devel@lists.xenproject.org
>> Cc: boris.ostrovsky@oracle.com
>> Cc: Juergen Gross <jgross@suse.com>
>
> Regarding the changes below:
>
> Acked-by: Juergen Gross <jgross@suse.com>
>

Thank you for your acked, I will re-post it.

Thanks,
	dou.
>
> Juergen
>
>> ---
>>  arch/x86/xen/enlighten_pv.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
>> index ae2a2e2..934dc7f 100644
>> --- a/arch/x86/xen/enlighten_pv.c
>> +++ b/arch/x86/xen/enlighten_pv.c
>> @@ -1232,6 +1232,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
>>  	x86_platform.get_nmi_reason = xen_get_nmi_reason;
>>
>>  	x86_init.resources.memory_setup = xen_memory_setup;
>> +	x86_init.irqs.intr_mode_init	= x86_init_noop;
>>  	x86_init.oem.arch_setup = xen_arch_setup;
>>  	x86_init.oem.banner = xen_banner;
>>
>>
>
>
>
>

Patch

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index ae2a2e2..934dc7f 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1232,6 +1232,7 @@  asmlinkage __visible void __init xen_start_kernel(void)
 	x86_platform.get_nmi_reason = xen_get_nmi_reason;
 
 	x86_init.resources.memory_setup = xen_memory_setup;
+	x86_init.irqs.intr_mode_init	= x86_init_noop;
 	x86_init.oem.arch_setup = xen_arch_setup;
 	x86_init.oem.banner = xen_banner;