From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH 10/10] KVM: arm/arm64: vgic: Allow non-shared device HW interrupts Date: Tue, 30 Jun 2015 22:19:03 +0200 Message-ID: <20150630201903.GX11332@cbox> References: <1433783045-8002-1-git-send-email-marc.zyngier@arm.com> <1433783045-8002-11-git-send-email-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Eric Auger , Alex =?iso-8859-1?Q?Benn=E9e?= , Andre Przywara To: Marc Zyngier Return-path: Received: from mail-la0-f41.google.com ([209.85.215.41]:35134 "EHLO mail-la0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323AbbF3UTF (ORCPT ); Tue, 30 Jun 2015 16:19:05 -0400 Received: by lagh6 with SMTP id h6so27373255lag.2 for ; Tue, 30 Jun 2015 13:19:03 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1433783045-8002-11-git-send-email-marc.zyngier@arm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Jun 08, 2015 at 06:04:05PM +0100, Marc Zyngier wrote: > So far, the only use of the HW interrupt facility is the timer, > implying that the active state is context-switched for each vcpu, > as the device is is shared across all vcpus. > > This does not work for a device that has been assigned to a VM, > as the guest is entierely in control of that device (the HW is > not shared). In that case, it makes sense to bypass the whole > active state switchint, and only track the deactivation of the > interrupt. > The discinction here between shared and non-shared feels a bit arbitrary (it may not be, but just feel that way) and I can't easily convince myself that this is the logical/correct/all-encompassing word to describe the nature of the two devices. Meh, not the most productive comment, I know... -Christoffer From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Tue, 30 Jun 2015 22:19:03 +0200 Subject: [PATCH 10/10] KVM: arm/arm64: vgic: Allow non-shared device HW interrupts In-Reply-To: <1433783045-8002-11-git-send-email-marc.zyngier@arm.com> References: <1433783045-8002-1-git-send-email-marc.zyngier@arm.com> <1433783045-8002-11-git-send-email-marc.zyngier@arm.com> Message-ID: <20150630201903.GX11332@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jun 08, 2015 at 06:04:05PM +0100, Marc Zyngier wrote: > So far, the only use of the HW interrupt facility is the timer, > implying that the active state is context-switched for each vcpu, > as the device is is shared across all vcpus. > > This does not work for a device that has been assigned to a VM, > as the guest is entierely in control of that device (the HW is > not shared). In that case, it makes sense to bypass the whole > active state switchint, and only track the deactivation of the > interrupt. > The discinction here between shared and non-shared feels a bit arbitrary (it may not be, but just feel that way) and I can't easily convince myself that this is the logical/correct/all-encompassing word to describe the nature of the two devices. Meh, not the most productive comment, I know... -Christoffer