[vbox-dev] Kernel v4.12 API changes

[Larry Finger]

On 05/29/2017 09:56 AM, Sérgio Basto wrote:
> On Fri, 2017-05-19 at 13:43 -0500, Larry Finger wrote:
>> On 05/19/2017 04:57 AM, Frank Mehnert wrote:
>>> On Mittwoch, 17. Mai 2017 20:49:42 CEST Frank Mehnert wrote:
>>>> Hi Larry,
>>>>
>>>> On Montag, 15. Mai 2017 16:35:30 CEST Larry Finger wrote:
>>>>> Has anyone found the magic elixir to allow VB to run with
>>>>> kernel 4.12-rc1?
>>>>>
>>>>> Adding #include <asm/set_memory.h> to
>>>>> vboxdrv/r0drv/linux/alloc-r0drv-linux.c is
>>>>> trivial; however, I'm having trouble with changes in the page
>>>>> table walk code in
>>>>> vboxdrv/r0drv/linux/memobj-r0drv-linux.c. I followed the
>>>>> changes in the kernel
>>>>> and I have code that compiles cleanly, but as soon as I try to
>>>>> start a VM, the
>>>>> system locks up and panics a few seconds later. At this point,
>>>>> I have no
>>>>> diagnostics concerning where the fault happened.
>>>>
>>>> we are working on a fix. The obvious fixes can be found in
>>>> r66927, r66928
>>>> and r66930. These changes make the modules compile against Linux
>>>> 4.12-rc1
>>>> but as you noticed, the kernel panics when starting a VM. We are
>>>> debugging
>>>> this issue.
>>>
>>> quick fix for the remaining issue (freeze on VM start) is the
>>> following:
>>>
>>> --- src/VBox/HostDrivers/Support/linux/SUPDrv-linux.c   (revision
>>> 115504)
>>> +++ src/VBox/HostDrivers/Support/linux/SUPDrv-linux.c   (working
>>> copy)
>>> @@ -1397,7 +1397,7 @@
>>>    SUPR0DECL(uint32_t) SUPR0GetKernelFeatures(void)
>>>    {
>>>        uint32_t fFlags = 0;
>>> -#ifdef CONFIG_PAX_KERNEXEC
>>> +#if defined(CONFIG_PAX_KERNEXEC) || LINUX_VERSION_CODE >=
>>> KERNEL_VERSION(4, 12, 0)
>>>        fFlags |= SUPKERNELFEATURES_GDT_READ_ONLY;
>>>    #endif
>>>    #if defined(VBOX_STRICT) ||
>>> defined(VBOX_WITH_EFLAGS_AC_SET_IN_VBOXDRV)
>>>
>>> The reason is that the GDT is mapped read-only as of Linux 4.12. We
>>> have
>>> not yet decided if this will be the final fix for the moment or if
>>> an
>>> alternative fix (which requires changes to the VMM part as well) is
>>> the
>>> better choice.
>>
>> Thanks for this update. At least the current set of patches will
>> allow VB to
>> build on my kernel, and when the Kernel:HEAD project at openSUSE
>> switches to
>> 4.12.0-rcX.
> 
> Hi , Larry
> 
> I expect to see yours patches in
> https://build.opensuse.org/package/show/Virtualization/virtualbox
> 
> but patches for 4.12.0-rcX still not published , could you send it to
> us ? , to apply on my VirtualBox package in RPMFusion  ...

Attached are my patches for the 4.12 kernel. This patch file is used to modify 
the tar file used to create the openSUSE RPM. The paths may need to be adjusted.

Larry


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