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From: "Alex Bennée" <alex.bennee@linaro.org>
To: Julien Grall <julien@xen.org>
Cc: xen-devel@lists.xenproject.org, masami.hiramatsu@linaro.org,
	ehem+xen@m5p.com, bertrand.marquis@arm.com,
	andre.przywara@arm.com, "Julien Grall" <jgrall@amazon.com>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Ian Jackson" <iwj@xenproject.org>,
	"Jan Beulich" <jbeulich@suse.com>, "Wei Liu" <wl@xen.org>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 0/4] xen/arm: Unbreak ACPI
Date: Wed, 30 Sep 2020 11:38:48 +0100
Message-ID: <874knfpn0n.fsf@linaro.org> (raw)
In-Reply-To: <a42d2724-4d9b-a177-35c7-44bd0250f265@xen.org>


Julien Grall <julien@xen.org> writes:

> Hi Alex,
>
> On 29/09/2020 22:11, Alex Bennée wrote:
>> 
>> Julien Grall <julien@xen.org> writes:
>> 
>>> Hi Alex,
>>>
>>> On 29/09/2020 16:29, Alex Bennée wrote:
>>>>
>>>> Julien Grall <julien@xen.org> writes:
>>>>
>>>>> From: Julien Grall <jgrall@amazon.com>
>>>>>
>>>>> Hi all,
>>>>>
>>>>> Xen on ARM has been broken for quite a while on ACPI systems. This
>>>>> series aims to fix it.
>>>>>
>>>>> Unfortunately I don't have a system with ACPI v6.0 or later (QEMU seems
>>>>> to only support 5.1). So I did only some light testing.
>>>>
>>>> I was hoping to get more diagnostics out to get it working under QEMU
>>>> TCG so I think must of missed a step:
>>>>
>>>>     Loading Xen 4.15-unstable ...
>>>>     Loading Linux 4.19.0-11-arm64 ...
>>>>     Loading initial ramdisk ...
>>>>     Using modules provided by bootloader in FDT
>>>>     Xen 4.15-unstable (c/s Sat Sep 26 21:55:42 2020 +0100 git:72f3d495d0) EFI loader
>>>>     ...silence...
>>>>
>>>> I have a grub installed from testing on a buster base:
>>>>
>>>>     dpkg --status grub-arm64-efi
>>>>     Version: 2.04-8
>>>>
>>>> With:
>>>>
>>>>     GRUB_CMDLINE_LINUX_DEFAULT=""
>>>>     GRUB_CMDLINE_LINUX="console=ttyAMA0"
>>>>     GRUB_CMDLINE_LINUX_XEN_REPLACE="console=hvc0 earlyprintk=xen"
>>>>     GRUB_CMDLINE_XEN="loglvl=all guest_loglvl=all com1=115200,8n1,0x3e8,5console=com1,vg"
>>>>
>>>> And I built Xen with --enable-systemd and tweaked the hypervisor .config:
>>>>
>>>>     CONFIG_EXPERT=y
>>>>     CONFIG_ACPI=y
>>>>
>>>> So any pointers to make it more verbose would be helpful.
>>>
>>> The error is hapenning before Xen setup the console. You can get early
>>> output on QEMU if you rebuild Xen with the following .config options:
>>>
>>> CONFIG_DEBUG=y
>>> CONFIG_EARLY_UART_CHOICE_PL011=y
>>> CONFIG_EARLY_UART_PL011=y
>>> CONFIG_EARLY_PRINTK=y
>>> CONFIG_EARLY_UART_BASE_ADDRESS=0x09000000
>>> CONFIG_EARLY_UART_PL011_BAUD_RATE=0
>>> CONFIG_EARLY_PRINTK_INC="debug-pl011.inc"
>> 
>> OK I can see it fails on the ACPI and then tries to fall back to FDT and
>> then fails to find the GIC:
>> 
>>    (XEN) CMDLINE[00000000f7bbe000]:chosen placeholder root=UUID=cf00cd3a-066b-4146-bedf-f811d3343077 ro console=hvc0 earlyprintk=xen
>>    (XEN)
>>    (XEN) Command line: placeholder loglvl=all guest_loglvl=all com1=115200,8n1,0x3e8,5console=com1,vg no-real-mode edd=off
>>    (XEN) parameter "placeholder" unknown!
>>    (XEN) parameter "no-real-mode" unknown!
>>    (XEN) parameter "edd" unknown!
>>    (XEN) ACPI: RSDP 138560000, 0024 (r2 BOCHS )
>>    (XEN) ACPI: XSDT 138550000, 004C (r1 BOCHS  BXPCFACP        1       1000013)
>>    (XEN) ACPI: FACP 138510000, 010C (r5 BOCHS  BXPCFACP        1 BXPC        1)
>>    (XEN) ACPI: DSDT 138520000, 14A6 (r2 BOCHS  BXPCDSDT        1 BXPC        1)
>>    (XEN) ACPI: APIC 138500000, 018C (r3 BOCHS  BXPCAPIC        1 BXPC        1)
>>    (XEN) ACPI: GTDT 1384F0000, 0060 (r2 BOCHS  BXPCGTDT        1 BXPC        1)
>>    (XEN) ACPI: MCFG 1384E0000, 003C (r1 BOCHS  BXPCMCFG        1 BXPC        1)
>>    (XEN) ACPI: SPCR 1384D0000, 0050 (r2 BOCHS  BXPCSPCR        1 BXPC        1)
>>    (XEN) Unsupported FADT revision 5.1, should be 6.0+, will disable ACPI
>>    (XEN) acpi_boot_table_init: FADT not found (-22)
>>    (XEN) Domain heap initialised
>>    (XEN) Booting using Device Tree
>>    (XEN) Platform: Generic System
>>    (XEN)
>>    (XEN) ****************************************
>>    (XEN) Panic on CPU 0:
>>    (XEN) Unable to find compatible GIC in the device tree
>>    (XEN) ****************************************
>>    (XEN)
>>    (XEN) Reboot in five seconds...
>> 
>> Despite saying it is going to reboot it never manages to. Any idea how
>> it is trying to reset the system?
>
> This is a bit of chicken and eggs problem. To know the reset method, you 
> need to parse the ACPI tables. As we can't parse then we don't know the 
> reset method. So, Xen will just do an infinite loop.

Well you do get some ACPI tables - downgrading the minimum at least
restores the reset method detection. I wonder if it would be worth
defaulting to PSCI if you don't know rather than hang indefinitely?

FWIW the failure after that is failing to find the GIC - I'm just
looking at the MADT table parsing now. Why am I getting a sense of
DejaVu?

> It would probably be good to be more forthcoming with the users and say 
> it will not reboot.
>
> Also, IIRC, the time subsystem is not yet initialized. So it might be 
> possible to mdelay() doesn't work properly.

Surely that's an architectural subsystem so there is no reason that
couldn't be up and running.

>
> Cheers,


-- 
Alex Bennée


  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-26 20:55 Julien Grall
2020-09-26 20:55 ` [PATCH 1/4] xen/acpi: Rework acpi_os_map_memory() and acpi_os_unmap_memory() Julien Grall
2020-09-28  8:18   ` Jan Beulich
2020-09-28  9:58     ` Julien Grall
2020-09-28 10:09       ` Jan Beulich
2020-09-28 10:39         ` Julien Grall
2020-10-10  9:49           ` Julien Grall
2020-10-10 10:04             ` Julien Grall
2020-09-29 11:10   ` Rahul Singh
2020-10-01  0:06   ` Stefano Stabellini
2020-10-01 15:09     ` Julien Grall
2020-09-26 20:55 ` [PATCH 2/4] xen/arm: acpi: The fixmap area should always be cleared during failure/unmap Julien Grall
2020-09-29 11:13   ` Rahul Singh
2020-10-01  0:30   ` Stefano Stabellini
2020-10-01 15:14     ` Julien Grall
2020-09-26 20:55 ` [PATCH 3/4] xen/arm: Check if the platform is not using ACPI before initializing Dom0less Julien Grall
2020-09-29 11:17   ` Rahul Singh
2020-09-30 23:26   ` Stefano Stabellini
2020-09-26 20:55 ` [PATCH 4/4] xen/arm: Introduce fw_unreserved_regions() and use it Julien Grall
2020-09-30 23:40   ` Stefano Stabellini
2020-10-01 15:34     ` Julien Grall
2020-09-27  1:47 ` [PATCH 0/4] xen/arm: Unbreak ACPI Elliott Mitchell
2020-09-29 15:28   ` Elliott Mitchell
2020-09-28  6:47 ` Masami Hiramatsu
2020-09-28 13:00   ` Masami Hiramatsu
2020-10-16 22:33     ` Xen-ARM EFI/ACPI problems (was: Re: [PATCH 0/4] xen/arm: Unbreak ACPI) Elliott Mitchell
2020-10-17  5:12       ` Elliott Mitchell
2020-10-08 18:39   ` [PATCH 0/4] xen/arm: Unbreak ACPI Elliott Mitchell
2020-10-09  9:39     ` Julien Grall
2020-10-09 14:22       ` Elliott Mitchell
2020-10-09 18:15         ` Julien Grall
2020-10-09 22:36           ` Elliott Mitchell
2020-10-09 21:49   ` Elliott Mitchell
2020-10-10 11:02   ` Julien Grall
2020-10-12 19:02     ` Stefano Stabellini
2020-10-12 21:34       ` Elliott Mitchell
2020-10-14  1:06         ` Stefano Stabellini
2020-10-14  1:37           ` Elliott Mitchell
2020-10-14 17:47             ` Julien Grall
2020-10-15 18:00               ` Stefano Stabellini
2020-10-14 17:44       ` Julien Grall
2020-09-29 11:10 ` Rahul Singh
2020-09-29 15:29 ` Alex Bennée
2020-09-29 17:07   ` Julien Grall
2020-09-29 21:11     ` Alex Bennée
2020-09-29 23:39       ` André Przywara
2020-09-30  8:51         ` Alex Bennée
2020-09-30 10:35         ` Julien Grall
2020-09-30  9:42       ` Julien Grall
2020-09-30 10:38         ` Alex Bennée [this message]
2020-09-30 11:10           ` Julien Grall

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