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From: David Vrabel <david.vrabel@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
	David Vrabel <david.vrabel@citrix.com>,
	xen-devel@lists.xenproject.org
Cc: Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCHv2 2/3] x86/fpu: Add a per-domain field to set the width of FIP/FDP
Date: Tue, 23 Feb 2016 11:53:14 +0000	[thread overview]
Message-ID: <56CC482A.4000204@citrix.com> (raw)
In-Reply-To: <56CC3E20.9070105@citrix.com>

On 23/02/16 11:10, Andrew Cooper wrote:
> On 23/02/16 11:05, David Vrabel wrote:
>> @@ -653,6 +657,12 @@ int arch_domain_create(struct domain *d, unsigned int domcr_flags,
>>      /* PV/PVH guests get an emulated PIT too for video BIOSes to use. */
>>      pit_init(d, cpu_khz);
>>  
>> +    /*
>> +     * If the FPU not to save FCS/FDS then we can always save/restore
> 
> "If the FPU does not" ?
> 
>> @@ -284,7 +284,11 @@ void xsave(struct vcpu *v, uint64_t mask)
>>              return;
>>          }
>>  
>> -        if ( word_size > 0 &&
>> +        /*
>> +         * If the FIP/FDP[63:32] are both zero, it is safe to use the
>> +         * 32-bit restore to also restore the selectors.
>> +         */
> 
> This comment is presumably applicable to the fxsave path?

Yes.  Do you want this comment added there?

David

  reply	other threads:[~2016-02-23 11:53 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-23 11:05 [PATCHv2 0/3] x86: workaround inability to fully restore FPU state David Vrabel
2016-02-23 11:05 ` [PATCHv2 1/3] x86/fpu: improve check for XSAVE* not writing FIP/FDP fields David Vrabel
2016-02-23 11:18   ` Andrew Cooper
2016-02-23 11:54     ` David Vrabel
2016-02-23 14:07       ` Jan Beulich
2016-02-23 14:59   ` Jan Beulich
2016-02-23 17:42     ` David Vrabel
2016-02-24  7:51       ` Jan Beulich
2016-02-24 10:37         ` Tian, Kevin
2016-02-24 10:49           ` Jan Beulich
2016-03-18 18:23             ` Lai, Paul C
2016-02-23 11:05 ` [PATCHv2 2/3] x86/fpu: Add a per-domain field to set the width of FIP/FDP David Vrabel
2016-02-23 11:10   ` Andrew Cooper
2016-02-23 11:53     ` David Vrabel [this message]
2016-02-23 15:24   ` Jan Beulich
2016-02-23 16:27     ` David Vrabel
2016-02-23 16:39       ` Jan Beulich
2016-02-23 11:05 ` [PATCHv2 3/3] x86/hvm: add HVM_PARAM_X87_FIP_WIDTH David Vrabel
2016-02-23 11:20   ` Andrew Cooper
2016-02-24 11:51     ` Wei Liu

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