Support of lguest?

Support of lguest?

[Juergen Gross]

Lguest and Xen pv-guests are the only users of pv_mmu_ops (with the
one exception of the .exit_mmap member, which is being used by Xen
HVM-guests, too).

As it is possible now to build a kernel without Xen pv-guest support
while keeping PVH and PVHVM support, I thought about putting most
pv_mmu_ops functions in #ifdef CONFIG_XEN_HAS_PVMMU sections. If there
wouldn't be lguest...

So my question: is anybody still using lguest or would like to keep it?

If yes, I'd add CONFIG_PARAVIRT_MMU selected by CONFIG_XEN_PV and
CONFIG_LGUEST_GUEST.

If no, I'd remove lguest support and just use CONFIG_XEN_HAS_PVMMU,
in case nobody would like me to use CONFIG_PARAVIRT_MMU even if
lguest isn't there any more.


Juergen

Re: Support of lguest?

[Vitaly Kuznetsov]

Juergen Gross <jgross@suse.com> writes:

> Lguest and Xen pv-guests are the only users of pv_mmu_ops (with the
> one exception of the .exit_mmap member, which is being used by Xen
> HVM-guests, too).
>
> As it is possible now to build a kernel without Xen pv-guest support
> while keeping PVH and PVHVM support, I thought about putting most
> pv_mmu_ops functions in #ifdef CONFIG_XEN_HAS_PVMMU sections.

There is an ongoing work to enable PV TLB flushing for Hyper-V guests:
http://driverdev.linuxdriverproject.org/pipermail/driverdev-devel/2017-April/104411.html

it utilizes .flush_tlb_others member in pv_mmu_ops.

hopefully, this work will be merged in 4.13.

-- 
  Vitaly

Re: Support of lguest?

[Juergen Gross]

On 15/05/17 16:22, Vitaly Kuznetsov wrote:
> Juergen Gross <jgross@suse.com> writes:
> 
>> Lguest and Xen pv-guests are the only users of pv_mmu_ops (with the
>> one exception of the .exit_mmap member, which is being used by Xen
>> HVM-guests, too).
>>
>> As it is possible now to build a kernel without Xen pv-guest support
>> while keeping PVH and PVHVM support, I thought about putting most
>> pv_mmu_ops functions in #ifdef CONFIG_XEN_HAS_PVMMU sections.
> 
> There is an ongoing work to enable PV TLB flushing for Hyper-V guests:
> http://driverdev.linuxdriverproject.org/pipermail/driverdev-devel/2017-April/104411.html
> 
> it utilizes .flush_tlb_others member in pv_mmu_ops.
> 
> hopefully, this work will be merged in 4.13.

Thanks for the information. I'll keep .flush_tlb_others member outside
the #ifdef section.


Juergen