From mboxrd@z Thu Jan 1 00:00:00 1970 From: julien.grall@citrix.com (Julien Grall) Date: Fri, 16 Oct 2015 17:49:35 +0100 Subject: [PATCH v2 3/3] xen/arm: don't try to re-register vcpu_info on cpu_hotplug. In-Reply-To: <1445013301-12624-3-git-send-email-stefano.stabellini@eu.citrix.com> References: <1445013301-12624-3-git-send-email-stefano.stabellini@eu.citrix.com> Message-ID: <56212A9F.5070202@citrix.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Stefano, On 16/10/15 17:35, Stefano Stabellini wrote: > Signed-off-by: Stefano Stabellini > --- > arch/arm/xen/enlighten.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c > index 6c09cc4..b193811 100644 > --- a/arch/arm/xen/enlighten.c > +++ b/arch/arm/xen/enlighten.c > @@ -93,6 +93,16 @@ static void xen_percpu_init(void) > int err; > int cpu = get_cpu(); > > + /* > + * VCPUOP_register_vcpu_info cannot be called twice for the same > + * vcpu, so if vcpu_info is already registered, just get out. This > + * can happen with cpu-hotplug. > + */ > + if (per_cpu(xen_vcpu, cpu) != NULL) { > + put_cpu(); > + return; > + } Not really related to this patch. By side effect this patch is also not calling irq_percpu_enable. Looking around, all the caller of irq_percpu_enable will call irq_percpu_disable when the CPU is dying. Is there any side effect to not doing this? Regards, > + > pr_info("Xen: initializing cpu%d\n", cpu); > vcpup = per_cpu_ptr(xen_vcpu_info, cpu); > > -- Julien Grall