From: Julien Grall <julien.grall@citrix.com>
To: David Vrabel <david.vrabel@citrix.com>, xen-devel@lists.xenproject.org
Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com,
Catalin Marinas <catalin.marinas@arm.com>,
x86@kernel.org, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] xen/events: Support event channel rebind on ARM
Date: Mon, 27 Jul 2015 13:43:46 +0100 [thread overview]
Message-ID: <55B62782.9050701__8390.05320235646$1438001155$gmane$org@citrix.com> (raw)
In-Reply-To: <55B62588.3050502@citrix.com>
On 27/07/15 13:35, David Vrabel wrote:
> On 27/07/15 12:35, Julien Grall wrote:
>> Currently, the event channel rebind code is gated with the presence of
>> the vector callback.
>>
>> The virtual interrupt controller on ARM has the concept of per-CPU
>> interrupt (PPI) which allow us to support per-VCPU event channel.
>> Therefore there is no need of vector callback for ARM.
>>
>> Xen is already using a free PPI to notify the guest VCPU of an event.
>> Furthermore, the xen code initialization in Linux (see
>> arch/arm/xen/enlighten.c) is requesting correctly a per-CPU IRQ.
>>
>> Introduce new helper xen_support_evtchn_rebind to allow architecture
>> decide whether rebind an event is support or not. It will always return
>> 1 on ARM and keep the same behavior on x86.
>>
>> This is also allow us to drop the usage of xen_have_vector_callback
>> entirely in the ARM code.
>
> This did not apply cleanly. Please always base patches on Linus's
> master branch.
My patch is based on Linus's master branch. Although, it has a
pre-requisite of [1] which I sent a few seconds before it. Though it's
only for applying because the 2 patches are not related.
I should have mentioned it in the mail, sorry.
> This also breaks the x86 build.
I forgot to test this new version when I turned the macro into a static
inline.
> /local/davidvr/work/k.org/tip/arch/x86/include/asm/xen/events.h: In
> function ‘xen_support_evtchn_rebind’:
> /local/davidvr/work/k.org/tip/arch/x86/include/asm/xen/events.h:29:85:
> error: ‘xen_have_vector_callback’ undeclared (first use in this function)
> return (!xen_hvm_domain() || xen_have_vector_callback);
>
>> --- a/arch/arm/include/asm/xen/events.h
>> +++ b/arch/arm/include/asm/xen/events.h
>> @@ -20,4 +20,10 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
>> atomic64_t, \
>> counter), (val))
>>
>> +/* Rebind event channel is supported by default */
>> +static inline bool xen_support_evtchn_rebind(void)
>> +{
>> + return 1;
>
> This should be true (similarly for arm64).
Will resend a new version, and remove the dependency on [1].
Regards,
[1] http://permalink.gmane.org/gmane.linux.kernel/2004690
--
Julien Grall
next prev parent reply other threads:[~2015-07-27 12:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1437996911-18985-1-git-send-email-julien.grall@citrix.com>
2015-07-27 12:35 ` [PATCH v2] xen/events: Support event channel rebind on ARM David Vrabel
[not found] ` <55B62588.3050502@citrix.com>
2015-07-27 12:43 ` Julien Grall [this message]
2015-07-27 11:35 Julien Grall
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