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[Xen-devel] [PATCH v3 3/4] Revert "xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests."

Zhenzhong Duan posted 4 patches 6 years, 7 months ago
There is a newer version of this series
[Xen-devel] [PATCH v3 3/4] Revert "xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests."
Posted by Zhenzhong Duan 6 years, 7 months ago 
This reverts commit 8d693b911bb9c57009c24cb1772d205b84c7985c.

Instead we use an unified parameter 'nopv' for all the hypervisor
platforms.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.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 |  4 ----
 arch/x86/xen/enlighten_hvm.c                    | 12 +-----------
 2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 21e08af..d5c3dcc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5251,10 +5251,6 @@
 			Disables the ticketlock slowpath using Xen PV
 			optimizations.
 
-	xen_nopv	[X86]
-			Disables the PV optimizations forcing the HVM guest to
-			run as generic HVM guest with no PV drivers.
-
 	xen_scrub_pages=	[XEN]
 			Boolean option to control scrubbing pages before giving them back
 			to Xen, for use by other domains. Can be also changed at runtime
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index ac4943c..7fcb4ea 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -210,18 +210,8 @@ static void __init xen_hvm_guest_init(void)
 #endif
 }
 
-static bool xen_nopv;
-static __init int xen_parse_nopv(char *arg)
-{
-       xen_nopv = true;
-       return 0;
-}
-early_param("xen_nopv", xen_parse_nopv);
-
 bool __init xen_hvm_need_lapic(void)
 {
-	if (xen_nopv)
-		return false;
 	if (xen_pv_domain())
 		return false;
 	if (!xen_hvm_domain())
@@ -233,7 +223,7 @@ bool __init xen_hvm_need_lapic(void)
 
 static uint32_t __init xen_platform_hvm(void)
 {
-	if (xen_pv_domain() || xen_nopv)
+	if (xen_pv_domain())
 		return 0;
 
 	return xen_cpuid_base();
-- 
1.8.3.1


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Re: [Xen-devel] [PATCH v3 3/4] Revert "xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests."
Posted by Boris Ostrovsky 6 years, 7 months ago 
On Mon, Jul 01, 2019 at 10:20:27AM +0800, Zhenzhong Duan wrote:
> This reverts commit 8d693b911bb9c57009c24cb1772d205b84c7985c.
> 
> Instead we use an unified parameter 'nopv' for all the hypervisor
> platforms.
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> Reviewed-by: Juergen Gross <jgross@suse.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 |  4 ----
>  arch/x86/xen/enlighten_hvm.c                    | 12 +-----------
>  2 files changed, 1 insertion(+), 15 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 21e08af..d5c3dcc 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5251,10 +5251,6 @@
>  			Disables the ticketlock slowpath using Xen PV
>  			optimizations.
>  
> -	xen_nopv	[X86]
> -			Disables the PV optimizations forcing the HVM guest to
> -			run as generic HVM guest with no PV drivers.
> -


So someone upgrades the kernel and suddenly things work differently?

At least there should be a warning that the option has been replaced
with 'nopv' (but I would actually keep this option working as well).

-boris



>  	xen_scrub_pages=	[XEN]
>  			Boolean option to control scrubbing pages before giving them back
>  			to Xen, for use by other domains. Can be also changed at runtime
> diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
> index ac4943c..7fcb4ea 100644
> --- a/arch/x86/xen/enlighten_hvm.c
> +++ b/arch/x86/xen/enlighten_hvm.c
> @@ -210,18 +210,8 @@ static void __init xen_hvm_guest_init(void)
>  #endif
>  }
>  
> -static bool xen_nopv;
> -static __init int xen_parse_nopv(char *arg)
> -{
> -       xen_nopv = true;
> -       return 0;
> -}
> -early_param("xen_nopv", xen_parse_nopv);
> -
>  bool __init xen_hvm_need_lapic(void)
>  {
> -	if (xen_nopv)
> -		return false;
>  	if (xen_pv_domain())
>  		return false;
>  	if (!xen_hvm_domain())
> @@ -233,7 +223,7 @@ bool __init xen_hvm_need_lapic(void)
>  
>  static uint32_t __init xen_platform_hvm(void)
>  {
> -	if (xen_pv_domain() || xen_nopv)
> +	if (xen_pv_domain())
>  		return 0;
>  
>  	return xen_cpuid_base();
> -- 
> 1.8.3.1
> 

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Re: [Xen-devel] [PATCH v3 3/4] Revert "xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests."
Posted by Zhenzhong Duan 6 years, 7 months ago 
On 2019/7/2 11:48, Boris Ostrovsky wrote:
> On Mon, Jul 01, 2019 at 10:20:27AM +0800, Zhenzhong Duan wrote:
>> This reverts commit 8d693b911bb9c57009c24cb1772d205b84c7985c.
>>
>> Instead we use an unified parameter 'nopv' for all the hypervisor
>> platforms.
>>
>> Signed-off-by: Zhenzhong Duan<zhenzhong.duan@oracle.com>
>> Reviewed-by: Juergen Gross<jgross@suse.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 |  4 ----
>>   arch/x86/xen/enlighten_hvm.c                    | 12 +-----------
>>   2 files changed, 1 insertion(+), 15 deletions(-)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 21e08af..d5c3dcc 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -5251,10 +5251,6 @@
>>   			Disables the ticketlock slowpath using Xen PV
>>   			optimizations.
>>   
>> -	xen_nopv	[X86]
>> -			Disables the PV optimizations forcing the HVM guest to
>> -			run as generic HVM guest with no PV drivers.
>> -
> So someone upgrades the kernel and suddenly things work differently?
>
> At least there should be a warning that the option has been replaced
> with 'nopv' (but I would actually keep this option working as well).

OK, I'll add new patch to map xen_nopv to nopv. So if 'xen_nopv' is 
used, we go

to the path for 'nopv'. I will be same effect.

Thanks

Zhenzhong


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