From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f182.google.com (mail-pd0-f182.google.com [209.85.192.182]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 447032C0097 for ; Tue, 4 Feb 2014 19:03:25 +1100 (EST) Received: by mail-pd0-f182.google.com with SMTP id v10so7963493pde.27 for ; Tue, 04 Feb 2014 00:03:21 -0800 (PST) Message-ID: <52F09EC0.60201@ozlabs.ru> Date: Tue, 04 Feb 2014 19:03:12 +1100 From: Alexey Kardashevskiy MIME-Version: 1.0 To: Alexander Graf Subject: Re: [PATCH] PPC: KVM: fix VCPU run for HV KVM References: <1389338467-26303-1-git-send-email-aik@ozlabs.ru> In-Reply-To: Content-Type: text/plain; charset=KOI8-R Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, "kvm@vger.kernel.org mailing list" , kvm-ppc@vger.kernel.org, "linux-kernel@vger.kernel.org list" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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. -- Alexey