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From: Andy Lutomirski <luto@amacapital.net>
To: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Feng Tang <feng.tang@intel.com>, Ingo Molnar <mingo@redhat.com>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>, X86 ML <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Zhang, Rui" <rui.zhang@intel.com>,
	"Kleen, Andi" <andi.kleen@intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Len Brown <len.brown@intel.com>
Subject: Re: [PATCH] x86/msr: Block writes to certain MSRs unconditionally
Date: Sun, 11 Apr 2021 09:57:20 -0700	[thread overview]
Message-ID: <C7F7BE8D-562B-4BC3-A209-8EDD7DAF0AAA@amacapital.net> (raw)
In-Reply-To: <20210411164342.GL3762101@tassilo.jf.intel.com>




> On Apr 11, 2021, at 9:43 AM, Andi Kleen <ak@linux.intel.com> wrote:
> 
> 
>> 
>> I have actually seen real user programs poke MSR_SYSCALL_MASK.
> 
> Hmm, what was the use case?
> 
> 

Working around a kernel bug.  The workaround only worked on AMD systems.  The correct solution was to fix the kernel bug, not poke MSRs.

  reply	other threads:[~2021-04-11 16:57 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-30  8:25 [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Feng Tang
2021-03-30  8:25 ` [RFC 2/2] x86/tsc: mark tsc reliable for qualified platforms Feng Tang
2021-04-10  9:27 ` [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Thomas Gleixner
2021-04-10  9:47   ` Borislav Petkov
2021-04-10 12:11     ` [PATCH] x86/msr: Block writes to certain MSRs unconditionally Borislav Petkov
2021-04-10 14:51       ` Andy Lutomirski
2021-04-10 15:33         ` [PATCH -v1.1] " Borislav Petkov
2021-04-10 18:52       ` [PATCH] " Andi Kleen
2021-04-11  9:40         ` Borislav Petkov
2021-04-11 16:03         ` Andy Lutomirski
2021-04-11 16:43           ` Andi Kleen
2021-04-11 16:57             ` Andy Lutomirski [this message]
2021-04-11 17:03               ` Borislav Petkov
2021-04-11 23:21                 ` Andy Lutomirski
2021-04-12  9:37                   ` Borislav Petkov
2021-04-10 14:48     ` [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Feng Tang
2021-04-10 15:38       ` Borislav Petkov
2021-04-10 18:43     ` Thomas Gleixner
2021-04-10 14:38   ` Feng Tang
2021-04-10 18:46     ` Thomas Gleixner
2021-04-11  7:21       ` Feng Tang

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