Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753677AbaBDIJ5 (ORCPT ); Tue, 4 Feb 2014 03:09:57 -0500 Received: from cantor2.suse.de ([195.135.220.15]:44887 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291AbaBDIJt convert rfc822-to-8bit (ORCPT ); Tue, 4 Feb 2014 03:09:49 -0500 Content-Type: text/plain; charset=US-ASCII Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Subject: Re: [PATCH] PPC: KVM: fix VCPU run for HV KVM From: Alexander Graf In-Reply-To: <52F09EC0.60201@ozlabs.ru> Date: Tue, 4 Feb 2014 09:09:44 +0100 Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras , kvm-ppc , "kvm@vger.kernel.org mailing list" , "linux-kernel@vger.kernel.org list" Content-Transfer-Encoding: 7BIT Message-Id: References: <1389338467-26303-1-git-send-email-aik@ozlabs.ru> <52F09EC0.60201@ozlabs.ru> To: Alexey Kardashevskiy X-Mailer: Apple Mail (2.1827) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04.02.2014, at 09:03, Alexey Kardashevskiy wrote: > On 01/13/2014 02:44 AM, Alexander Graf wrote: >> >> On 10.01.2014, at 08:21, Alexey Kardashevskiy wrote: >> >>> When write to MMIO happens and there is an ioeventfd for that and >>> is handled successfully, ioeventfd_write() returns 0 (success) and >>> kvmppc_handle_store() returns EMULATE_DONE. Then kvmppc_emulate_mmio() >>> converts EMULATE_DONE to RESUME_GUEST_NV and this broke from the loop. >>> >>> This adds handling of RESUME_GUEST_NV in kvmppc_vcpu_run_hv(). >>> >>> Cc: Michael S. Tsirkin >>> Suggested-by: Paul Mackerras >>> Signed-off-by: Alexey Kardashevskiy >>> --- >>> >>> This definitely needs a better commit message. Please, help. >>> ps. it seems like ioeventfd never worked on ppc64. hm. >>> >>> --- >>> arch/powerpc/kvm/book3s_hv.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c >>> index 072287f..24f363f 100644 >>> --- a/arch/powerpc/kvm/book3s_hv.c >>> +++ b/arch/powerpc/kvm/book3s_hv.c >>> @@ -1569,7 +1569,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) >>> vcpu->arch.fault_dar, vcpu->arch.fault_dsisr); >>> srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx); >>> } >>> - } while (r == RESUME_GUEST); >>> + } while ((r == RESUME_GUEST_NV) || (r == RESUME_GUEST)); >> >> How about >> >> while(!(r & RESUME_FLAG_HOST)); > > > Rather "while(!(r & RESUME_FLAG_HOST) && (r > 0));" and still not obvious > that this is really better. > > Paul agrees with the original patch (and made a better commit message for > our internal tree) but I just cannot make him reply in this thread, keep > constantly asking him but to no avail :) > > >> That should cover all RESUME_GUEST_XXX cases just fine. Apart from that >> I agree that we should check for ! FLAG_HOST bit rather than the actual >> RESUME_GUEST value in all case where we check for it (read: please >> update all places). > > There are 3 places remotely similar to this and none of them requires a fix > like above. Not today. Then someone goes in and realizes that CEDE advanced version 8 should clear r15 at which point you have to set RESUME_GUEST_NV and are in the same mess again. Let's just always treat RESUME_GUEST_NV and RESUME_GUEST as identical when checking for it. If you like, add a small helper like static inline bool is_resume_guest(int r) { return (r == RESUME_GUEST || r == RESUME_GUEST_NV); } in a header and use that one instead. That way we're guaranteed to be consistent. Alex -- 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/