From: AKASHI Takahiro <takahiro.akashi@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Kyle McMartin <kmcmarti@redhat.com>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
Mark Rutland <Mark.Rutland@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
"geoff@infradead.org" <geoff@infradead.org>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"broonie@kernel.org" <broonie@kernel.org>,
"david.griego@linaro.org" <david.griego@linaro.org>,
"christoffer.dall@linaro.org" <christoffer.dall@linaro.org>,
"freddy77@gmail.com" <freddy77@gmail.com>
Subject: Re: [RFC v2 0/5] arm64: kvm: reset hyp context for kexec
Date: Tue, 31 Mar 2015 15:04:44 +0900 [thread overview]
Message-ID: <551A38FC.1040801@linaro.org> (raw)
In-Reply-To: <55190F45.1070803@linaro.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 <takahiro.akashi@linaro.org> 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.
>>
next prev parent reply other threads:[~2015-03-31 6:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-26 8:25 [RFC v2 0/5] arm64: kvm: reset hyp context for kexec AKASHI Takahiro
2015-03-26 8:25 ` [RFC v2 1/5] arm64: kvm: add a cpu tear-down function AKASHI Takahiro
2015-03-26 8:25 ` [RFC v2 2/5] arm64: kvm: allow EL2 context to be reset on shutdown AKASHI Takahiro
2015-03-26 8:25 ` [RFC v2 3/5] arm64: kvm: add cpu reset hook for cpu hotplug AKASHI Takahiro
2015-03-26 8:25 ` [RFC v2 4/5] arm64: kvm: add cpu reset at module exit AKASHI Takahiro
2015-03-26 8:25 ` [RFC v2 5/5] arm: kvm: add stub implementation for kvm_cpu_reset() AKASHI Takahiro
2015-03-27 15:31 ` [RFC v2 0/5] arm64: kvm: reset hyp context for kexec Kyle McMartin
2015-03-27 15:37 ` Marc Zyngier
2015-03-27 17:40 ` Kyle McMartin
2015-03-27 17:50 ` Marc Zyngier
2015-03-30 1:39 ` AKASHI Takahiro
2015-03-30 7:16 ` Marc Zyngier
2015-03-30 8:54 ` AKASHI Takahiro
2015-03-31 6:04 ` AKASHI Takahiro [this message]
2015-03-31 7:31 ` Marc Zyngier
2015-04-01 5:06 ` AKASHI Takahiro
2015-04-01 9:05 ` Marc Zyngier
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