From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Steven Noonan <steven@uplinklabs.net>,
kernel@collabora.com
Subject: Re: Direct rdtsc call side-effect
Date: Thu, 01 Jun 2023 12:31:22 +0200 [thread overview]
Message-ID: <87jzwneao5.ffs@tglx> (raw)
In-Reply-To: <20230601085602.GR4253@hirez.programming.kicks-ass.net>
On Thu, Jun 01 2023 at 10:56, Peter Zijlstra wrote:
> On Thu, Jun 01, 2023 at 01:45:35PM +0500, Muhammad Usama Anjum wrote:
>> We are thinking of saving and restoring the timestamp counter at suspend
>> and resume time respectively. In theory it can work on Intel because of
>> TSC_ADJUST register. But it'll never work on AMD until:
>> * AMD supports the same kind of adjust register. (AMD has said that the
>> adjust register cannot be implemented in their firmware. They'll have to
>> add it to their hardware.)
>> * by manual synchronization in kernel (I know you don't like this idea. But
>> there is something Windows is doing to save/restore and sync the TSC)
>
> Wine could set TIF_NOTSC, which will cause it to run with CR4.TSD
> cleared and cause RDTSC to #GP, at which point you can emulate it.
We should ask Microsoft to do the same. That'll fix the direct RDTSC
usage quickly. :)
next prev parent reply other threads:[~2023-06-01 10:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-01 8:45 Direct rdtsc call side-effect Muhammad Usama Anjum
2023-06-01 8:56 ` Peter Zijlstra
2023-06-01 8:58 ` Peter Zijlstra
2023-06-01 10:31 ` Thomas Gleixner [this message]
2023-06-01 10:26 ` Thomas Gleixner
2023-06-01 18:20 ` Thomas Gleixner
2023-06-01 19:07 ` Steven Noonan
2023-06-01 19:31 ` H. Peter Anvin
2023-06-01 20:10 ` Thomas Gleixner
2023-06-01 20:13 ` Thomas Gleixner
2023-06-01 20:31 ` Peter Zijlstra
2023-06-01 21:41 ` Steven Noonan
2023-06-02 6:45 ` Peter Zijlstra
2023-06-05 10:27 ` David Laight
2023-06-05 14:43 ` Thomas Gleixner
2023-06-05 15:54 ` David Laight
2023-06-05 16:32 ` H. Peter Anvin
2023-06-06 8:23 ` David Laight
2023-06-09 0:14 ` H. Peter Anvin
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