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Subject: Re: [PATCH v2 3/7] x86: Add nopv parameter to disable PV extensions
To:     Zhenzhong Duan <zhenzhong.duan@oracle.com>,
        linux-kernel@vger.kernel.org
Cc:     tglx@linutronix.de, mingo@kernel.org, bp@alien8.de, hpa@zytor.com,
        boris.ostrovsky@oracle.com, sstabellini@kernel.org,
        peterz@infradead.org, srinivas.eeda@oracle.com,
        Ingo Molnar <mingo@redhat.com>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        xen-devel@lists.xenproject.org
References: <1561377779-28036-1-git-send-email-zhenzhong.duan@oracle.com>
 <1561377779-28036-4-git-send-email-zhenzhong.duan@oracle.com>
From:   Juergen Gross <jgross@suse.com>
Message-ID: <23b5bdee-f6b8-609b-2a52-d0b8c10a8ff8@suse.com>
Date:   Wed, 26 Jun 2019 11:38:39 +0200
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On 24.06.19 14:02, Zhenzhong Duan wrote:
> In virtualization environment, PV extensions (drivers, interrupts,
> timers, etc) are enabled in the majority of use cases which is the
> best option.
> 
> However, in some cases (kexec not fully working, benchmarking)
> we want to disable PV extensions. As such introduce the
> 'nopv' parameter that will do it.
> 
> There are guest types which just won't work without PV extensions,
> like Xen PV, Xen PVH and jailhouse. add a "ignore_nopv" member to
> struct hypervisor_x86 set to true for those guest types and call
> the detect functions only if nopv is false or ignore_nopv is true.
> 
> There is already 'xen_nopv' parameter for XEN platform but not for
> others. 'xen_nopv' can then be removed with this change.
> 
> Suggested-by: Juergen Gross <jgross@suse.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Jan Kiszka <jan.kiszka@siemens.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: xen-devel@lists.xenproject.org

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen