From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752353AbbCaGE4 (ORCPT ); Tue, 31 Mar 2015 02:04:56 -0400 Received: from mail-pd0-f173.google.com ([209.85.192.173]:34893 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750898AbbCaGEy (ORCPT ); Tue, 31 Mar 2015 02:04:54 -0400 Message-ID: <551A38FC.1040801@linaro.org> Date: Tue, 31 Mar 2015 15:04:44 +0900 From: AKASHI Takahiro User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Marc Zyngier CC: Kyle McMartin , Catalin Marinas , Will Deacon , Mark Rutland , "linux-arm-kernel@lists.infradead.org" , "linaro-kernel@lists.linaro.org" , "geoff@infradead.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "broonie@kernel.org" , "david.griego@linaro.org" , "christoffer.dall@linaro.org" , "freddy77@gmail.com" Subject: Re: [RFC v2 0/5] arm64: kvm: reset hyp context for kexec References: <1427358326-3708-1-git-send-email-takahiro.akashi@linaro.org> <20150327153131.GK12400@redacted.bos.redhat.com> <55157920.3050003@arm.com> <20150327174044.GL12400@redacted.bos.redhat.com> <5518A969.3090707@linaro.org> <20150330081613.60ff7dc0@arm.com> <55190F45.1070803@linaro.org> In-Reply-To: <55190F45.1070803@linaro.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Marc, On 03/30/2015 05:54 PM, AKASHI Takahiro wrote: > On 03/30/2015 04:16 PM, Marc Zyngier wrote: >> On Mon, 30 Mar 2015 02:39:53 +0100 >> AKASHI Takahiro wrote: >> >>> On 03/28/2015 02:40 AM, Kyle McMartin wrote: >>>> On Fri, Mar 27, 2015 at 03:37:04PM +0000, Marc Zyngier wrote: >>>>>> [ 236.260863] Kernel panic - not syncing: HYP panic: >>>>>> [ 236.260863] PS:600003c9 PC:000003ffffff0830 ESR:0000000096000006 >>>>> >>>>> It would be interesting if you could find out what you have at offset >>>>> 0x830 of hyp-init.o (the stack trace is for EL1, and is not going to >>>>> help much). >>>>> >>>> >>>> Given the alignment, i'm going to assume i'm looking at the right thing: >>>> >>>> 0000000000000820 <__kvm_hyp_reset>: >>>> 820: d51c2000 msr ttbr0_el2, x0 >>>> 824: d5033fdf isb >>>> 828: d50c871f tlbi alle2 >>>> 82c: d5033f9f dsb sy >>>> 830: 10000060 adr x0, 83c <__kvm_hyp_reset+0x1c> >>>> 834: b3403c01 bfxil x1, x0, #0, #16 >>>> 838: d61f0020 br x1 >>>> 83c: d53c1000 mrs x0, sctlr_el2 >>>> >>>> but it seems fairly implausible to be trapping on ADR x0, 1f... >>> >>> >>> I've never seen this panic on fast model... >>> >>> ESR shows that >>> - Exception class: Data abort taken without a change in Exception level >>> - Data fault status code: Translation fault at EL2 >>> >>> and FAR seems not to be a proper address. >> >> ... which is consistent with what we're seeing here (data fault on >> something that doesn't generate a load/store). I'm pretty sure the >> page tables are screwed. >> >> Have you tested it with 64k pages? > > Hmm... It seems that I was able to reproduce the problem if 64k pages enabled. The entry address in trampoline code calc'ed by kvm_virt_to_trampoline(__kvm_hyp_reset) seems to be wrong due to improper page-alignment in hyp-init.S. The following patch fixed this problem, at least, in my environment(fast model). (I don't know why it's PAGE_SHIFT - 1, not PAGE_SHIFT.) >diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >index d212990..45b8d98 100644 >--- a/arch/arm64/kvm/hyp-init.S >+++ b/arch/arm64/kvm/hyp-init.S >@@ -24,7 +24,7 @@ > .text > .pushsection .hyp.idmap.text, "ax" > >- .align 11 >+ .align (PAGE_SHIFT - 1) > > ENTRY(__kvm_hyp_init) > ventry __invalid // Synchronous EL2t After applying this patch, I got another problem with kexec-tools on 64k page kernel, but I've already modified kexec-tools. Thanks, -Takahiro AKASHI > -Takahiro AKASHI > >> Thanks, >> >> M. >>