From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Xin Li <xin@zytor.com>, Andrew Cooper <andrew.cooper3@citrix.com>,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org,
peterz@infradead.org, seanjc@google.com
Subject: Re: [PATCH v1 2/3] x86/msr: Switch between WRMSRNS and WRMSR with the alternatives mechanism
Date: Sat, 17 Aug 2024 23:16:36 -0700 [thread overview]
Message-ID: <b5221fb0-a198-4c76-ae47-906c42442f5c@zytor.com> (raw)
In-Reply-To: <20240818054911.GAZsGLV1MAEMLk9RiP@fat_crate.local>
On 8/17/24 22:49, Borislav Petkov wrote:
> On Sat, Aug 17, 2024 at 12:22:22PM -0700, H. Peter Anvin wrote:
>> The padding avoids unnecessary NOPs.
>
> And a NOP vs some other prefix to have one less insn matters practically
> how exactly here?
Pretty much nothing, but it is zero cost and possibly some insanely
small gain.
-hpa
next prev parent reply other threads:[~2024-08-18 6:17 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-07 5:47 [PATCH v1 0/3] x86: Write FRED RSP0 on return to userspace Xin Li (Intel)
2024-08-07 5:47 ` [PATCH v1 1/3] x86/entry: Test ti_work for zero before processing individual bits Xin Li (Intel)
2024-08-07 16:21 ` Brian Gerst
2024-08-07 23:03 ` Xin Li
2024-08-07 18:08 ` Thomas Gleixner
2024-08-07 18:21 ` Thomas Gleixner
2024-08-07 23:01 ` Xin Li
2024-08-07 5:47 ` [PATCH v1 2/3] x86/msr: Switch between WRMSRNS and WRMSR with the alternatives mechanism Xin Li (Intel)
2024-08-07 18:11 ` Thomas Gleixner
2024-08-09 23:07 ` Andrew Cooper
2024-08-10 0:01 ` H. Peter Anvin
2024-08-10 0:25 ` Andrew Cooper
2024-08-16 17:52 ` Xin Li
2024-08-16 18:40 ` Andrew Cooper
2024-08-16 19:18 ` H. Peter Anvin
2024-08-16 21:45 ` Andrew Cooper
2024-08-16 21:26 ` H. Peter Anvin
2024-08-16 22:27 ` Andrew Cooper
2024-08-16 22:34 ` Andrew Cooper
2024-08-16 23:03 ` H. Peter Anvin
2024-08-16 22:59 ` H. Peter Anvin
2024-08-17 23:51 ` H. Peter Anvin
2024-08-17 14:23 ` Borislav Petkov
2024-08-17 14:43 ` Borislav Petkov
2024-08-17 15:44 ` Xin Li
2024-08-17 19:22 ` H. Peter Anvin
2024-08-18 5:59 ` Borislav Petkov
2024-08-17 19:22 ` H. Peter Anvin
2024-08-18 5:49 ` Borislav Petkov
2024-08-18 6:16 ` H. Peter Anvin [this message]
2024-08-07 5:47 ` [PATCH v1 3/3] x86/entry: Set FRED RSP0 on return to userspace instead of context switch Xin Li (Intel)
2024-08-07 18:39 ` Thomas Gleixner
2024-08-07 21:55 ` Sean Christopherson
2024-08-07 23:04 ` Thomas Gleixner
2024-08-09 10:45 ` Nikolay Borisov
2024-08-09 17:37 ` Xin Li
2024-08-09 22:43 ` H. Peter Anvin
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