From: Dave Hansen <dave.hansen@linux.intel.com>
To: Keno Fischer <keno@juliacomputing.com>
Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Borislav Petkov" <bp@suse.de>,
"Andi Kleen" <andi@firstfloor.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Kyle Huey" <khuey@kylehuey.com>,
"Robert O'Callahan" <robert@ocallahan.org>
Subject: Re: [RFC PATCH] x86/arch_prctl: Add ARCH_SET_XCR0 to mask XCR0 per-thread
Date: Mon, 18 Jun 2018 10:29:05 -0700 [thread overview]
Message-ID: <2b212eb7-6bcd-1767-0ed5-2f137c7d33d6@linux.intel.com> (raw)
In-Reply-To: <CABV8kRzqaxNwS-eyLCUr13eQVYjUvr=Nf=G3gch_tB9Aqo2A2A@mail.gmail.com>
On 06/18/2018 10:22 AM, Keno Fischer wrote:
>> No, I'm saying that depending on faults is not a viable solution. We
>> are not guaranteed to get faults in all the cases you would need to fix up.
>>
>> XSAVE*/XRSTOR* are not even *called* in some of those cases.
> Ah, my apologies, I was under the mistaken impression that xsaves also
> read xcomp_bv to inform the layout, rather than using the RFBM and then
> updating the xcomp_bv field. Let me think about this some more and see
> what I can come up with.
It's not even that. If you do this, xstate_comp_offsets[] will
potentially need to be recalculated for each XCR0 value. Granted, we've
pretty nicely consolidated these references in the kernel into very few
spots, but you still need to fix that up.
next prev parent reply other threads:[~2018-06-18 17:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-17 0:33 [RFC PATCH] x86/arch_prctl: Add ARCH_SET_XCR0 to mask XCR0 per-thread Keno Fischer
2018-06-17 16:35 ` Andi Kleen
2018-06-17 16:48 ` Keno Fischer
2018-06-17 18:22 ` Keno Fischer
2018-06-18 16:58 ` Andi Kleen
2018-06-18 17:50 ` Keno Fischer
2018-06-19 13:43 ` Andi Kleen
2018-06-18 12:47 ` Dave Hansen
2018-06-18 14:42 ` Keno Fischer
2018-06-18 15:04 ` Dave Hansen
2018-06-18 15:13 ` Keno Fischer
2018-06-18 16:16 ` Dave Hansen
2018-06-18 17:22 ` Keno Fischer
2018-06-18 17:29 ` Dave Hansen [this message]
2018-06-18 17:43 ` Dave Hansen
2018-06-18 18:16 ` Keno Fischer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2b212eb7-6bcd-1767-0ed5-2f137c7d33d6@linux.intel.com \
--to=dave.hansen@linux.intel.com \
--cc=andi@firstfloor.org \
--cc=bp@suse.de \
--cc=hpa@zytor.com \
--cc=keno@juliacomputing.com \
--cc=khuey@kylehuey.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=rkrcmar@redhat.com \
--cc=robert@ocallahan.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox