From mboxrd@z Thu Jan 1 00:00:00 1970 From: Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [PATCH v2 2/9] KVM: Add documentation for VCPU requests Date: Thu, 6 Apr 2017 14:29:07 +0200 Message-ID: <20170406122907.GI6369@potion> References: <20170331160658.4331-1-drjones@redhat.com> <20170331160658.4331-3-drjones@redhat.com> <985f69f3-3a4b-3742-731e-aac3a26b1777@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Jones , kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, cdall@linaro.org, marc.zyngier@arm.com, pbonzini@redhat.com To: Christian Borntraeger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:58670 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754077AbdDFM3L (ORCPT ); Thu, 6 Apr 2017 08:29:11 -0400 Content-Disposition: inline In-Reply-To: <985f69f3-3a4b-3742-731e-aac3a26b1777@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: 2017-04-06 12:18+0200, Christian Borntraeger: > On 03/31/2017 06:06 PM, Andrew Jones wrote: >> Signed-off-by: Andrew Jones >> +VCPU Requests and Guest Mode >> +============================ > > FWIW, s390 does not implement the guest mode. Maybe add some words that not > all architectures implement that? Or do we expect Radims rework soon? Yes, mention that it is an optional optimization sounds good. I won't be adding guest->mode to s390 (at least in the beginning). This means that kvm_arch_vcpu_should_kick() should return true. In kvm_make_all_cpus_request(), there is kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE that ought to be replaced with kvm_arch_vcpu_should_kick(), and it should return true if the arch doesn't implement guest->mode. But on s390, the condition currently always returns false ... is that IPI-less behavior of kvm_make_all_cpus_request intended on s390? Thanks.