Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755670Ab3J1HZD (ORCPT ); Mon, 28 Oct 2013 03:25:03 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:37846 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753488Ab3J1HZA (ORCPT ); Mon, 28 Oct 2013 03:25:00 -0400 MIME-Version: 1.0 Date: Mon, 28 Oct 2013 12:54:57 +0530 Message-ID: Subject: ARM GIC Virtualization question From: Mj Embd To: "linux-kernel@vger.kernel.org" , linaro-kernel , Simon Glass Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1014 Lines: 27 Hi All, a) As per GIC-400 all Physical interrupts trap into hypervisor b) Hypervisor does ACK, programs Virtual GIC list registers (with PhysIRQ:VIRQ) and does a world switch. c) GIC CPU I/f interrupts Guest with the VIRQ d) Guest does a ACK and EOI to GIC cpu i/f e) Hypervisor gets a maintenance interrupt when Guest Does an EOI f) Hypervisor then clears the Physical Interrupt So for 1 interrupt there are so many context switches ? Is the sequence right. If I am missing anything please let me know .. Also, If a device is private to a guest, so many context switches would reduce the performance if the device interrupts a lot. My question is that a) Is the above flow correct ? b) Is this the only flow or there exists some optimisations Thanks and Regards -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/