From: "Jan Beulich" <jbeulich@suse.com>
To: shuai.ruan@linux.intel.com
Cc: andrew.cooper3@citrix.com, keir@xen.org, xen-devel@lists.xen.org
Subject: Re: [PATCH V7 3/3] x86/xsaves: ebx may return wrong value using CPUID eax=0xdh, ecx =1
Date: Wed, 06 Apr 2016 18:29:39 -0600 [thread overview]
Message-ID: <5705B80302000078000E5E7D@prv-mh.provo.novell.com> (raw)
In-Reply-To: <20160406070034.GA26357@shuai.ruan@linux.intel.com>
>>> Shuai Ruan <shuai.ruan@linux.intel.com> 04/06/16 8:59 AM >>>
>Another question is whether we should add this in pv_cpuid() or not.
>(which we have discussed in the previous thread).
>
>Refer to SDM Volume 1
>"13.2 ENUMERATION OF CPU SUPPORT FOR XSAVE INSTRUCTIONS AND XSAVE-
>SUPPORTED FEATURES"
>— CPUID function 0DH, sub-function 1.
>...
>"EBX enumerates the size (in bytes) required by the XSAVES instruction
>for an XSAVE area containing all
>the state components corresponding to bits currently set in XCR0 |
>IA32_XSS."
>
>From the descriptions above, EBX only be used when XSAVES is enabled.
>So I think we should not deal with pv_cpuid() here.
If it's mandated to be XSAVES only - yes. But why are you asking such a question?
It was you who proposed the change to pv_cpuid(), and it is you who should be
understanding the specifics of the various pieces of CPUID output related to XSAVE
better than me.
Jan
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prev parent reply other threads:[~2016-04-07 0:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-31 8:57 [PATCH V7 0/3] xsaves bug fix Shuai Ruan
2016-03-31 8:57 ` [PATCH V7 1/3] x86/xsaves: fix overwriting between non-lazy/lazy xsaves Shuai Ruan
2016-04-04 15:51 ` Jan Beulich
2016-04-05 5:30 ` Shuai Ruan
[not found] ` <20160405053023.GA16876@shuai.ruan@linux.intel.com>
2016-04-05 7:17 ` Jan Beulich
2016-04-05 7:29 ` Shuai Ruan
2016-04-25 6:51 ` Jan Beulich
2016-04-29 1:36 ` Shuai Ruan
[not found] ` <20160429013616.GB4359@shuai.ruan@linux.intel.com>
2016-04-29 7:05 ` Jan Beulich
2016-03-31 8:57 ` [PATCH V7 2/3] x86/xsaves: fix two remained issues Shuai Ruan
2016-04-04 16:03 ` Jan Beulich
2016-03-31 8:57 ` [PATCH V7 3/3] x86/xsaves: ebx may return wrong value using CPUID eax=0xdh, ecx =1 Shuai Ruan
2016-04-05 8:31 ` Jan Beulich
2016-04-06 7:01 ` Shuai Ruan
[not found] ` <20160406070034.GA26357@shuai.ruan@linux.intel.com>
2016-04-07 0:29 ` Jan Beulich [this message]
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