linux-kernel - [PATCH v2 0/3] Fix small issues in XSAVES

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Date:   Thu, 12 Dec 2019 13:08:52 -0800
From:   Yu-cheng Yu <yu-cheng.yu@...el.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        Rik van Riel <riel@...riel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Yu-cheng Yu <yu-cheng.yu@...el.com>
Subject: [PATCH v2 0/3] Fix small issues in XSAVES

Rebase v1 to Linux v5.5-rc1.  This supersedes the previous version, but
does not have any functional changes.

The first two patches in this series are split from my supervisor xstate
patches [2].  The third is to fix a vital issue in __fpu_restore_sig(),
and more RFC than the others.  All three are not directly related to
supervisor xstates or CET, split them out and submit first.  I will
re-submit supervisor xstate patches shortly.

When__fpu_restore_sig() fails, partially cleared FPU registers still belong
to the previous owner task.  That causes that task to use corrupted xregs.
Fix it by doing __cpu_invalidate_fpregs_state() in functions that copy into
fpregs.  Further details are in the commit log of patch #3.

[1] v1 of this series:
    https://lkml.kernel.org/r/20191205182648.32257-1-yu-cheng.yu@intel.com/

[2] Support XSAVES supervisor states
    https://lkml.kernel.org/r/20190925151022.21688-1-yu-cheng.yu@intel.com/

[3] CET patches:
    https://lkml.kernel.org/r/20190813205225.12032-1-yu-cheng.yu@intel.com/
    https://lkml.kernel.org/r/20190813205359.12196-1-yu-cheng.yu@intel.com/

Yu-cheng Yu (3):
  x86/fpu/xstate: Fix small issues before adding supervisor xstates
  x86/fpu/xstate: Make xfeature_is_supervisor()/xfeature_is_user()
    return bool
  x86/fpu/xstate: Invalidate fpregs when __fpu_restore_sig() fails

 arch/x86/include/asm/fpu/internal.h | 14 ++++++++++++++
 arch/x86/kernel/fpu/core.c          | 16 ++++++++++++++--
 arch/x86/kernel/fpu/xstate.c        | 18 ++++++++----------
 3 files changed, 36 insertions(+), 12 deletions(-)

-- 
2.17.1