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Groups > linux.kernel > #1641719 > unrolled thread

Support of lguest?

Started byJuergen Gross <jgross@suse.com>
First post2017-05-15 16:10 +0200
Last post2017-05-15 16:30 +0200
Articles 3 — 2 participants

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  Support of lguest? Juergen Gross <jgross@suse.com> - 2017-05-15 16:10 +0200
    Re: Support of lguest? Juergen Gross <jgross@suse.com> - 2017-05-15 16:30 +0200
    Re: Support of lguest? Vitaly Kuznetsov <vkuznets@redhat.com> - 2017-05-15 16:30 +0200

#1641719 — Support of lguest?

FromJuergen Gross <jgross@suse.com>
Date2017-05-15 16:10 +0200
SubjectSupport of lguest?
Message-ID<tHoRb-KQ-13@gated-at.bofh.it>
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

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#1641744

FromJuergen Gross <jgross@suse.com>
Date2017-05-15 16:30 +0200
Message-ID<tHpay-Ra-23@gated-at.bofh.it>
In reply to#1641719
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

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#1641750

FromVitaly Kuznetsov <vkuznets@redhat.com>
Date2017-05-15 16:30 +0200
Message-ID<tHpay-Ra-25@gated-at.bofh.it>
In reply to#1641719
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

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