xen/arm: VCPUOP_register_vcpu_info fails with CONFIG_ARM64_64K_PAGES

xen/arm: VCPUOP_register_vcpu_info fails with CONFIG_ARM64_64K_PAGES

[Vijay Kilari]

Hi,

   Dom0 fails to boot with Xen with CONFIG_ARM64_64K_PAGES enabled because of
map_vcpu_info() make check of page offset based of PAGE_SIZE which is 4K in Xen.
Is this know issue that is fixed?. I am using 4.5 rc1 Xen code base.

Log below:

(XEN) DOM0: [    0.173539] If your platform has any non-coherent DMA
devices, they won't work properly.
(XEN) DOM0: [    0.187465] xen:grant_table: Grant tables using version
1 layout
(XEN) DOM0: [    0.194591] Grant table initialized
(XEN) DOM0: [    0.199085] xen:events: Using 2-level ABI
(XEN) DOM0: [    0.204377] Xen: initializing cpu0
(XEN) DOM0: [    0.216753] BUG: failure at
arch/arm64/xen/../../arm/xen/enlighten.c:172/xen_percpu_init()!
(XEN) DOM0: [    0.226269] Kernel panic - not syncing: BUG!
(XEN) DOM0: [    0.231570] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
3.18.0-02198-ge893fd8-dirty #3
(XEN) DOM0: [    0.240498] Call trace:
(XEN) DOM0: [    0.243975] [<fffffe0000087690>]
dump_backtrace+0x0/0x170
(XEN) DOM0: [    0.250456] [<fffffe0000087820>] show_stack+0x20/0x30
(XEN) DOM0: [    0.256579] [<fffffe00008818cc>] dump_stack+0x74/0x94
(XEN) DOM0: [    0.262699] [<fffffe000087cf2c>] panic+0xec/0x244
(XEN) DOM0: [    0.268461] [<fffffe0000093bd0>]
xen_percpu_init+0xe0/0xe8
(XEN) DOM0: [    0.275038] [<fffffe0000c474cc>]
xen_guest_init+0x2d0/0x300
(XEN) DOM0: [    0.281703] [<fffffe0000080df4>]
do_one_initcall+0xf4/0x200
(XEN) DOM0: [    0.288365] [<fffffe0000c40ae0>]
kernel_init_freeable+0xfc/0x264
(XEN) DOM0: [    0.295483] [<fffffe000087aecc>] kernel_init+0x1c/0xe0
(XEN) DOM0: [    0.301692] ---[ end Kernel panic - not syncing: BUG!

Regards
Vijay

Re: xen/arm: VCPUOP_register_vcpu_info fails with CONFIG_ARM64_64K_PAGES

[Ian Campbell]

On Wed, 2015-03-25 at 12:22 +0530, Vijay Kilari wrote:
> Hi,
> 
>    Dom0 fails to boot with Xen with CONFIG_ARM64_64K_PAGES enabled because of
> map_vcpu_info() make check of page offset based of PAGE_SIZE which is 4K in Xen.
> Is this know issue that is fixed?. I am using 4.5 rc1 Xen code base.

Julien has done some work with 64K pages, but I don't know if he has
fixed this specific issue. In any case as it stands 64K pages are not
yet supported under Xen (it's mostly a kernel side issue though).

Ian.

Re: xen/arm: VCPUOP_register_vcpu_info fails with CONFIG_ARM64_64K_PAGES

[Julien Grall]

Hi,

On 25/03/15 10:10, Ian Campbell wrote:
> On Wed, 2015-03-25 at 12:22 +0530, Vijay Kilari wrote:
>> Hi,
>>
>>    Dom0 fails to boot with Xen with CONFIG_ARM64_64K_PAGES enabled because of
>> map_vcpu_info() make check of page offset based of PAGE_SIZE which is 4K in Xen.
>> Is this know issue that is fixed?. I am using 4.5 rc1 Xen code base.
> 
> Julien has done some work with 64K pages, but I don't know if he has
> fixed this specific issue. In any case as it stands 64K pages are not
> yet supported under Xen (it's mostly a kernel side issue though).

This VCPUOP_register_vcpu issue is one problem among many others.

I'm working on adding support for 64K pages with Xen in the kernel. So
far, I have a guest booting with disk support and dom0 booting.

Regards,

-- 
Julien Grall