From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 01 Jul 2015 09:26:59 +0100 Subject: [PATCH 10/10] KVM: arm/arm64: vgic: Allow non-shared device HW interrupts In-Reply-To: <20150630201903.GX11332@cbox> References: <1433783045-8002-1-git-send-email-marc.zyngier@arm.com> <1433783045-8002-11-git-send-email-marc.zyngier@arm.com> <20150630201903.GX11332@cbox> Message-ID: <5593A453.4090903@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 30/06/15 21:19, Christoffer Dall wrote: > 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. Does the idea of global vs private resource feel more correct? M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH 10/10] KVM: arm/arm64: vgic: Allow non-shared device HW interrupts Date: Wed, 01 Jul 2015 09:26:59 +0100 Message-ID: <5593A453.4090903@arm.com> References: <1433783045-8002-1-git-send-email-marc.zyngier@arm.com> <1433783045-8002-11-git-send-email-marc.zyngier@arm.com> <20150630201903.GX11332@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150630201903.GX11332@cbox> Sender: kvm-owner@vger.kernel.org To: Christoffer Dall Cc: "kvm@vger.kernel.org" , "kvmarm@lists.cs.columbia.edu" , "linux-arm-kernel@lists.infradead.org" , Eric Auger , =?windows-1252?Q?Alex_Benn=E9e?= , Andre Przywara List-Id: kvmarm@lists.cs.columbia.edu On 30/06/15 21:19, Christoffer Dall wrote: > 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. Does the idea of global vs private resource feel more correct? M. -- Jazz is not dead. It just smells funny...