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Date:   Sat, 21 Jan 2023 20:44:38 -0800
From:   "H. Peter Anvin" <hpa@zytor.com>
To:     Dave Hansen <dave.hansen@intel.com>,
        "Li, Xin3" <xin3.li@intel.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
CC:     "x86@kernel.org" <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: the x86 sysret_rip test fails on the Intel FRED architecture
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On January 21, 2023 8:34:09 PM PST, Dave Hansen <dave=2Ehansen@intel=2Ecom>=
 wrote:
>On 1/21/23 19:38, Li, Xin3 wrote:
>>> However, it doesn't seem to make sense to do so to me=2E The current b=
ehavior is
>>> much more of an artifact than desired behavior=2E
>> We kind of have an agreement that %r11 =3D %flags after returning from =
the kernel=2E
>>=20
>> And the question is, is it what we want?
>
>Can the selftest just set r11=3Drflags before the syscall?  The old
>syscall entry path will set r11=3Drflags=2E  The FRED path won't touch it=
=2E
>Either case will pass an r11=3D=3Drflags check=2E

That's a good idea=2E