From: Borislav Petkov <bp@alien8.de>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Pavel Machek <pavel@ucw.cz>, Chen Yu <yu.c.chen@intel.com>,
Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h
Date: Thu, 15 Aug 2019 23:05:47 +0200 [thread overview]
Message-ID: <20190815210547.GL15313@zn.tnic> (raw)
In-Reply-To: <a24a2c7d-cfab-a049-37e8-7260a9063a7c@citrix.com>
On Thu, Aug 15, 2019 at 09:59:03PM +0100, Andrew Cooper wrote:
> If you're virtualised, the write to MSR_AMD64_CPUID_FN_1 almost
> certainly won't take effect, which means userspace will still be able to
> see the bit.
msr_clear_bit() has a return value. We should check it before
doing anything further. I hope the HV actually signals the write
success/failure properly so that we get a correct return value.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-08-15 21:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 21:17 [PATCH] x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16h Lendacky, Thomas
2019-08-14 23:24 ` Non-random RDRAND " Pavel Machek
2019-08-14 23:38 ` Pavel Machek
2019-08-15 13:01 ` Lendacky, Thomas
2019-08-15 15:12 ` Theodore Y. Ts'o
2019-08-16 9:07 ` Pavel Machek
2019-08-16 14:42 ` Neil Horman
2019-08-15 7:21 ` Borislav Petkov
2019-08-15 13:47 ` Lendacky, Thomas
2019-08-15 15:34 ` Borislav Petkov
2019-08-15 20:14 ` Thomas Gleixner
2019-08-15 20:59 ` Andrew Cooper
2019-08-15 21:04 ` Thomas Gleixner
2019-08-15 21:05 ` Borislav Petkov [this message]
2019-08-15 21:25 ` Andrew Cooper
2019-08-17 8:44 ` Borislav Petkov
2019-08-17 11:43 ` Andrew Cooper
2019-08-18 16:32 ` Thomas Gleixner
2019-08-16 15:19 ` Andy Lutomirski
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