From: "Bae, Chang Seok" <chang.seok.bae@intel.com>
To: "Liu, Jing2" <jing2.liu@intel.com>
Cc: "bp@suse.de" <bp@suse.de>, "luto@kernel.org" <luto@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@kernel.org" <mingo@kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"Brown, Len" <len.brown@intel.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to support dynamic xstate
Date: Thu, 7 Jan 2021 18:40:21 +0000 [thread overview]
Message-ID: <29CB32F5-1E73-46D4-BF92-18AD05F53E8E@intel.com> (raw)
In-Reply-To: <BYAPR11MB3256BBBB24F9131D99CF7EF5A9AF0@BYAPR11MB3256.namprd11.prod.outlook.com>
> On Jan 7, 2021, at 17:41, Liu, Jing2 <jing2.liu@intel.com> wrote:
>
> static void kvm_save_current_fpu(struct fpu *fpu) {
> + struct fpu *src_fpu = ¤t->thread.fpu;
> +
> /*
> * If the target FPU state is not resident in the CPU registers, just
> * memcpy() from current, else save CPU state directly to the target.
> */
> - if (test_thread_flag(TIF_NEED_FPU_LOAD))
> - memcpy(&fpu->state, ¤t->thread.fpu.state,
> + if (test_thread_flag(TIF_NEED_FPU_LOAD)) {
> + memcpy(&fpu->state, &src_fpu->state,
> fpu_kernel_xstate_min_size);
> For kvm, if we assume that it does not support dynamic features until this series,
> memcpy for only fpu->state is correct.
> I think this kind of assumption is reasonable and we only make original xstate work.
>
> - else
> + } else {
> + if (fpu->state_mask != src_fpu->state_mask)
> + fpu->state_mask = src_fpu->state_mask;
>
> Though dynamic feature is not supported in kvm now, this function still need
> consider more things for fpu->state_mask.
Can you elaborate this? Which path might be affected by fpu->state_mask
without dynamic state supported in KVM?
> I suggest that we can set it before if...else (for both cases) and not change other.
I tried a minimum change here. The fpu->state_mask value does not impact the
memcpy(). So, why do we need to change it for both?
Thanks,
Chang
next prev parent reply other threads:[~2021-01-07 18:41 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 15:56 [PATCH v3 00/21] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2020-12-23 15:56 ` [PATCH v3 01/21] x86/fpu/xstate: Modify initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-01-15 12:40 ` Borislav Petkov
2020-12-23 15:56 ` [PATCH v3 02/21] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-01-15 12:50 ` Borislav Petkov
2021-01-19 18:50 ` Bae, Chang Seok
2021-01-20 20:53 ` Borislav Petkov
2021-01-20 21:12 ` Bae, Chang Seok
2020-12-23 15:56 ` [PATCH v3 03/21] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-01-15 13:06 ` Borislav Petkov
2020-12-23 15:57 ` [PATCH v3 04/21] x86/fpu/xstate: Modify context switch helpers " Chang S. Bae
2021-01-15 13:18 ` Borislav Petkov
2021-01-19 18:49 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 05/21] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-01-15 13:39 ` Borislav Petkov
2021-01-15 19:47 ` Bae, Chang Seok
2021-01-19 15:57 ` Borislav Petkov
2021-01-19 18:57 ` Bae, Chang Seok
2021-01-22 10:56 ` Borislav Petkov
2021-01-27 1:23 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 06/21] x86/fpu/xstate: Calculate and remember dynamic xstate buffer sizes Chang S. Bae
2021-01-22 11:44 ` Borislav Petkov
2021-01-27 1:23 ` Bae, Chang Seok
2021-01-27 9:38 ` Borislav Petkov
2021-02-03 2:54 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 07/21] x86/fpu/xstate: Introduce helpers to manage dynamic xstate buffers Chang S. Bae
2021-01-26 20:17 ` Borislav Petkov
2021-01-27 1:23 ` Bae, Chang Seok
2021-01-27 10:41 ` Borislav Petkov
2021-02-03 4:10 ` Bae, Chang Seok
2021-02-04 13:10 ` Borislav Petkov
2021-02-03 4:10 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 08/21] x86/fpu/xstate: Define the scope of the initial xstate data Chang S. Bae
2021-02-08 12:33 ` Borislav Petkov
2021-02-08 18:53 ` Bae, Chang Seok
2021-02-09 12:49 ` Borislav Petkov
2021-02-09 15:38 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 09/21] x86/fpu/xstate: Introduce wrapper functions to organize xstate buffer access Chang S. Bae
2021-02-08 12:33 ` Borislav Petkov
2021-02-09 15:50 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to support dynamic xstate Chang S. Bae
2021-01-07 8:41 ` Liu, Jing2
2021-01-07 18:40 ` Bae, Chang Seok [this message]
2021-01-12 2:52 ` Liu, Jing2
2021-01-15 4:59 ` Bae, Chang Seok
2021-01-15 5:45 ` Liu, Jing2
2021-02-08 12:33 ` Borislav Petkov
2021-02-09 15:48 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 11/21] x86/fpu/xstate: Update xstate buffer address finder " Chang S. Bae
2021-02-19 15:00 ` Borislav Petkov
2021-02-19 19:19 ` Bae, Chang Seok
2020-12-23 15:57 ` [PATCH v3 12/21] x86/fpu/xstate: Update xstate context copy function to support dynamic buffer Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 13/21] x86/fpu/xstate: Expand dynamic context switch buffer on first use Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 14/21] x86/fpu/xstate: Support ptracer-induced xstate buffer expansion Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 15/21] x86/fpu/xstate: Extend the table to map xstate components with features Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 16/21] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 17/21] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 18/21] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 19/21] selftest/x86/amx: Include test cases for the AMX state management Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 20/21] x86/fpu/xstate: Support dynamic user state in the signal handling path Chang S. Bae
2020-12-23 15:57 ` [PATCH v3 21/21] x86/fpu/xstate: Introduce boot-parameters to control some state component support Chang S. Bae
2020-12-23 18:37 ` Randy Dunlap
2021-01-14 21:31 ` Bae, Chang Seok
2021-01-14 21:31 ` [PATCH v3 00/21] x86: Support Intel Advanced Matrix Extensions Bae, Chang Seok
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=29CB32F5-1E73-46D4-BF92-18AD05F53E8E@intel.com \
--to=chang.seok.bae@intel.com \
--cc=bp@suse.de \
--cc=dave.hansen@intel.com \
--cc=jing2.liu@intel.com \
--cc=kvm@vger.kernel.org \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=ravi.v.shankar@intel.com \
--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;
as well as URLs for NNTP newsgroup(s).