From: Thomas Gleixner <tglx@linutronix.de>
To: "Xin Li (Intel)" <xin@zytor.com>, linux-kernel@vger.kernel.org
Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com, peterz@infradead.org,
andrew.cooper3@citrix.com, seanjc@google.com
Subject: Re: [PATCH v1 2/3] x86/msr: Switch between WRMSRNS and WRMSR with the alternatives mechanism
Date: Wed, 07 Aug 2024 20:11:12 +0200 [thread overview]
Message-ID: <871q302ofz.ffs@tglx> (raw)
In-Reply-To: <20240807054722.682375-3-xin@zytor.com>
On Tue, Aug 06 2024 at 22:47, Xin Li wrote:
>
> +/* Instruction opcode for WRMSRNS supported in binutils >= 2.40 */
> +#define WRMSRNS _ASM_BYTES(0x0f,0x01,0xc6)
> +
> +/* Non-serializing WRMSR, when available. Falls back to a serializing WRMSR. */
> static __always_inline void wrmsrns(u32 msr, u64 val)
> {
> - __wrmsrns(msr, val, val >> 32);
> + /*
> + * WRMSR is 2 bytes. WRMSRNS is 3 bytes. Pad WRMSR with a redundant
> + * DS prefix to avoid a trailing NOP.
> + */
> + asm volatile("1: "
> + ALTERNATIVE("ds wrmsr",
> + WRMSRNS, X86_FEATURE_WRMSRNS)
Please get rid of this horrible line break. You have 100 characters line width.
Thanks,
tglx
next prev parent reply other threads:[~2024-08-07 18:11 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 [this message]
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
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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