From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v2 2/2] x86/hvm: Don't intercept #UD
 exceptions in general
Date: Wed, 27 Jan 2016 19:57:00 +0000
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To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Jan Beulich <JBeulich@suse.com>, Xen-devel <xen-devel@lists.xen.org>, Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>, Jun Nakajima <jun.nakajima@intel.com>, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
List-Id: xen-devel@lists.xenproject.org

On 27/01/2016 19:52, Konrad Rzeszutek Wilk wrote:
>> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
>> index 674feea..7a15d49 100644
>> --- a/xen/arch/x86/hvm/hvm.c
>> +++ b/xen/arch/x86/hvm/hvm.c
>> @@ -93,12 +93,10 @@ unsigned long __section(".bss.page_aligned")
>>  static bool_t __initdata opt_hap_enabled = 1;
>>  boolean_param("hap", opt_hap_enabled);
>>  
>> -#ifndef NDEBUG
>> +#ifndef opt_hvm_fep
>>  /* Permit use of the Forced Emulation Prefix in HVM guests */
>> -static bool_t opt_hvm_fep;
>> +bool_t opt_hvm_fep;
>>  boolean_param("hvm_fep", opt_hvm_fep);
> Since you remove the debug option you should probably also update the 
> documentation which says: ">Recognized in debug builds of the hypervisor only."

This doesn't change the "debug-only"-ness of the option.

Observe in the first hunk to hvm.h that opt_hvm_fep is defined to 0 in a
non-debug build, which causes this hunk to be omitted.

This actually matches the original introduction of opt_hvm_fep, before
it was reduced in scope to only hvm.c.  I now need it available again in
other translation units.

~Andrew