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Subject: Re: [PATCH v4 5/5] xen: Add 'xen_nopv' parameter back for backward
 compatibility
To:     Zhenzhong Duan <zhenzhong.duan@oracle.com>,
        linux-kernel@vger.kernel.org
Cc:     xen-devel@lists.xenproject.org, jgross@suse.com,
        sstabellini@kernel.org, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de
References: <1561958399-28906-1-git-send-email-zhenzhong.duan@oracle.com>
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From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Message-ID: <603e1c8a-408b-360d-9a84-6d91b5f1db1b@oracle.com>
Date:   Tue, 2 Jul 2019 14:13:33 -0400
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On 7/1/19 1:19 AM, Zhenzhong Duan wrote:
> Map 'xen_nopv' to 'nopv' and mark 'xen_nopv' obsolete in
> kernel-parameters.txt

I am not sure we want patch #3, why not do everything in a single patch?


>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Stefano Stabellini <sstabellini@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>  arch/x86/xen/enlighten_hvm.c                    | 7 +++++++
>  2 files changed, 13 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index d5c3dcc..34eb323 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5264,6 +5264,12 @@
>  			improve timer resolution at the expense of processing
>  			more timer interrupts.
>  
> +	xen_nopv	[X86]
> +			Disables the PV optimizations forcing the HVM guest to
> +			run as generic HVM guest with no PV drivers.
> +			This option is obsoleted by the "nopv" option, which
> +			has equivalent effect for XEN platform.
> +
>  	nopv=		[X86,XEN,KVM,HYPER_V,VMWARE]
>  			Disables the PV optimizations forcing the guest to run
>  			as generic guest with no PV drivers. Currently support
> diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
> index 340dff8..5cdd608 100644
> --- a/arch/x86/xen/enlighten_hvm.c
> +++ b/arch/x86/xen/enlighten_hvm.c
> @@ -211,6 +211,13 @@ static void __init xen_hvm_guest_init(void)
>  #endif
>  }
>  
> +static __init int xen_parse_nopv(char *arg)
> +{
> +	nopv = true;

pr_notice("\"xen_nopv\" is deprecated, please use \"nopv\" instead\n");


-boris

> +	return 0;
> +}
> +early_param("xen_nopv", xen_parse_nopv);
> +
>  bool __init xen_hvm_need_lapic(void)
>  {
>  	if (xen_pv_domain())