From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: v4.9-rc1 fails booting as a guest on ARM64 Cavium ThunderX Date: Fri, 21 Oct 2016 09:45:20 +0100 Message-ID: References: <924fd627-329a-54e0-694c-a9bdf979f696@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Robert Richter , daniel.thompson@linaro.org To: Auger Eric , "kvm@vger.kernel.org" , "kvmarm@lists.cs.columbia.edu" , Christoffer Dall Return-path: In-Reply-To: <924fd627-329a-54e0-694c-a9bdf979f696@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org +Robert On 21/10/16 08:01, Auger Eric wrote: > Hi, > > I am not able to boot 4.9-rc1 as a guest on Cavium ThunderX (dt and acpi > mode). Bisecting the guest shows that the problem shows up at > > 91ef84428a86b75a52e15c6fe4f56b446ba75f93 > irqchip/gic-v3: Reset BPR during initialization > > If I remove the write to the ICC_BPR1_EL1 register on guest, the VM boots. That's very odd. A ICC_BPR1_EL1 access when HCR_EL2.IMO is set only affects ICH_VMCR_EL2.VBPR1. It is not trapped, since we don't set ICH_HCR_EL2.TALL1. It is a very boring sysreg! So from a pure architectural point of view, I don't see how this can fail. I've just run the same configuration on my Freescale board (GICv3 as well), and can't see any issue at all. > Investigating KVM code ... What is the failure syndrome? Do you see it crashing? Locking up? What is the PC at that stage? Thanks, M. -- Jazz is not dead. It just smells funny...