From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755544AbbDIOTK (ORCPT ); Thu, 9 Apr 2015 10:19:10 -0400 Received: from static.88-198-71-155.clients.your-server.de ([88.198.71.155]:59529 "EHLO socrates.bennee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751805AbbDIOTH (ORCPT ); Thu, 9 Apr 2015 10:19:07 -0400 References: <1427814488-28467-1-git-send-email-alex.bennee@linaro.org> <1427814488-28467-5-git-send-email-alex.bennee@linaro.org> <20150401175529.642f64af@thinkpad-w530> <20150409122806.GB3212@hawk.usersys.redhat.com> From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Andrew Jones Cc: David Hildenbrand , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org, marc.zyngier@arm.com, peter.maydell@linaro.org, agraf@suse.de, pbonzini@redhat.com, zhichao.huang@linaro.org, jan.kiszka@siemens.com, r65777@freescale.com, bp@suse.de, Gleb Natapov , Jonathan Corbet , Russell King , "open list\:DOCUMENTATION" , open list Subject: Re: [PATCH v2 04/10] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl In-reply-to: <20150409122806.GB3212@hawk.usersys.redhat.com> Date: Thu, 09 Apr 2015 15:19:07 +0100 Message-ID: <8738491j1g.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 127.0.0.1 X-SA-Exim-Mail-From: alex.bennee@linaro.org X-SA-Exim-Scanned: No (on socrates.bennee.com); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Jones writes: > On Wed, Apr 01, 2015 at 05:55:29PM +0200, David Hildenbrand wrote: >> > This commit adds a stub function to support the KVM_SET_GUEST_DEBUG >> > ioctl. Currently any operation flag will return EINVAL. Actual >> >> Well it won't return -EINVAL if you push in KVM_GUESTDBG_ENABLE or 0. >> >> "Any unsupported flag will return -EINVAL. For now, only KVM_GUESTDBG_ENABLE is >> supported, although it won't have any effects." >> >> > functionality will be added with further patches. >> > >> > Signed-off-by: Alex Bennée . >> > >> > --- >> > v2 >> > - simplified form of the ioctl (stuff will go into setup_debug) >> > >> > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt >> > index b112efc..06c5064 100644 >> > --- a/Documentation/virtual/kvm/api.txt >> > +++ b/Documentation/virtual/kvm/api.txt >> > @@ -2604,7 +2604,7 @@ handled. >> > 4.87 KVM_SET_GUEST_DEBUG >> > >> > Capability: KVM_CAP_SET_GUEST_DEBUG >> > -Architectures: x86, s390, ppc >> > +Architectures: x86, s390, ppc, arm64 >> > Type: vcpu ioctl >> > Parameters: struct kvm_guest_debug (in) >> > Returns: 0 on success; -1 on error >> > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c >> > index 5560f74..445933d 100644 >> > --- a/arch/arm/kvm/arm.c >> > +++ b/arch/arm/kvm/arm.c >> > @@ -183,6 +183,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> > case KVM_CAP_ARM_PSCI: >> > case KVM_CAP_ARM_PSCI_0_2: >> > case KVM_CAP_READONLY_MEM: >> > + case KVM_CAP_SET_GUEST_DEBUG: >> > r = 1; >> > break; >> > case KVM_CAP_COALESCED_MMIO: >> > @@ -303,10 +304,21 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) >> > kvm_arm_set_running_vcpu(NULL); >> > } >> > >> > +#define KVM_GUESTDBG_VALID (KVM_GUESTDBG_ENABLE) >> >> That makes me rather think that it is another flag. >> >> We(s390x) use VALID_GUESTDBG_FLAGS, what about that or KVM_GUESTDBG_VALID_MASK? >> >> > + >> > int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, >> > struct kvm_guest_debug *dbg) >> > { >> > - return -EINVAL; >> > + if (dbg->control & KVM_GUESTDBG_ENABLE) { >> > + if (dbg->control & ~KVM_GUESTDBG_VALID) >> > + return -EINVAL; >> >> I'd move that check directly to the start of the function and bail out on any >> unsupported flag. >> >> > + >> > + vcpu->guest_debug = dbg->control; >> > + } else { >> > + /* If not enabled clear all flags */ >> > + vcpu->guest_debug = 0; >> > + } >> > + return 0; >> > } >> > >> > >> >> David >> > > I don't see any follow-up from Alex on this, so I feel the need to > "+1" all David's comments here. Yeah they make sense. Will do. -- Alex Bennée