From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] KVM: x86: Kick VCPU outside PIC lock again Date: Wed, 24 Feb 2010 11:28:44 +0100 Message-ID: <4B84FF5C.5090603@siemens.com> References: <20100217135901.331576359@linutronix.de> <4B842A1F.50601@siemens.com> <4B84F466.2080009@siemens.com> <4B84F5D4.5020202@redhat.com> <4B84F765.5040209@siemens.com> <4B84F9AF.8060804@redhat.com> <4B84FBDB.1070006@siemens.com> <4B84FCBB.8070702@redhat.com> <4B84FDF5.5080106@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Thomas Gleixner , KVM , Gleb Natapov , RT , Linux Kernel Mailing List To: Avi Kivity Return-path: In-Reply-To: <4B84FDF5.5080106@siemens.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Jan Kiszka wrote: > Avi Kivity wrote: >> On 02/24/2010 12:13 PM, Jan Kiszka wrote: >>> >>>> I see. Won't we hit the same issue when we call pic functions from >>>> atomic context during the guest entry sequence? >>>> >>>> >>> If there are such call paths, for sure. What concrete path(s) do you >>> have in mind? >>> >>> >> vcpu_enter_guest() -> inject_pending_event() -> >> kvm_cpu_{has,get}_interrupt() -> various pic functions if you're unlucky. > > But do they kick anyone or just check/pull information? Never saw any > warnings during my tests last year (granted: with older -rt and kvm > versions). Mmh, they could if there is > 1 IRQ pending. Guess this just never triggered in real life due to typical APIC use and low IRQ load during PIC times in my tests. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux