From: Juergen Gross <jgross@suse.com>
To: Zhenzhong Duan <zhenzhong.duan@oracle.com>, linux-kernel@vger.kernel.org
Cc: sstabellini@kernel.org, mingo@kernel.org, bp@alien8.de,
hpa@zytor.com, xen-devel@lists.xenproject.org,
boris.ostrovsky@oracle.com, tglx@linutronix.de
Subject: Re: [Xen-devel] [PATCH 3/6] x86: Add nopv parameter to disable PV extensions
Date: Mon, 24 Jun 2019 15:07:46 +0200 [thread overview]
Message-ID: <ed451198-9953-7b2d-4963-b60d3015bb5b@suse.com> (raw)
In-Reply-To: <1561294903-6166-3-git-send-email-zhenzhong.duan@oracle.com>
On 23.06.19 15:01, 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 is already 'xen_nopv' parameter for XEN platform but not for
> others. 'xen_nopv' can then be removed with this change.
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> Cc: xen-devel@lists.xenproject.org
> ---
> Documentation/admin-guide/kernel-parameters.txt | 4 ++++
> arch/x86/kernel/cpu/hypervisor.c | 11 +++++++++++
> 2 files changed, 15 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 138f666..b352f36 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5268,6 +5268,10 @@
> improve timer resolution at the expense of processing
> more timer interrupts.
>
> + nopv= [X86]
> + Disables the PV optimizations forcing the guest to run
> + as generic guest with no PV drivers.
> +
> xirc2ps_cs= [NET,PCMCIA]
> Format:
> <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
> diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
> index 479ca47..4f2c875 100644
> --- a/arch/x86/kernel/cpu/hypervisor.c
> +++ b/arch/x86/kernel/cpu/hypervisor.c
> @@ -85,10 +85,21 @@ static void __init copy_array(const void *src, void *target, unsigned int size)
> to[i] = from[i];
> }
>
> +static bool nopv;
> +static __init int xen_parse_nopv(char *arg)
You really don't want to use the "xen_" prefix here.
Juergen
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next prev parent reply other threads:[~2019-06-24 13:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1561294903-6166-1-git-send-email-zhenzhong.duan@oracle.com>
2019-06-23 13:01 ` [Xen-devel] [PATCH 3/6] x86: Add nopv parameter to disable PV extensions Zhenzhong Duan
2019-06-24 13:07 ` Juergen Gross [this message]
2019-06-24 13:18 ` Juergen Gross
2019-06-24 13:50 ` Zhenzhong Duan
2019-06-23 13:01 ` [Xen-devel] [PATCH 4/6] Revert "xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests." Zhenzhong Duan
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