From: "H. Peter Anvin" <hpa@zytor.com>
To: Khalid Ali <khaliidcaliy@gmail.com>,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com
Cc: x86@kernel.org, ardb@kernel.org, ubizjak@gmail.com,
brgerst@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] x86/boot: Avoid writing to cr4 twice in startup_64()
Date: Tue, 15 Jul 2025 13:31:35 -0700 [thread overview]
Message-ID: <1f809e9d-5383-469d-8c31-10f8230b79b8@zytor.com> (raw)
In-Reply-To: <20250715181709.1040-1-khaliidcaliy@gmail.com>
On 2025-07-15 11:16, Khalid Ali wrote:
> From: Khalid Ali <khaliidcaliy@gmail.com>
>
> When Initializing cr4 bit PSE and PGE, cr4 is written twice for
> each bit. This is redundancy.
>
> Instead, set both bits first and write CR4 once, avoiding redundant
> writes. This makes consistent with cr0 writes, which is set bits and
> write once.
>
> Signed-off-by: Khalid Ali <khaliidcaliy@gmail.com>
In case this wasn't obvious, this is:
Nacked-by: H. Peter Anvin (Intel) <hpa@zytor.com>
... with extreme prejudice.
-hpa
next prev parent reply other threads:[~2025-07-15 20:32 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-15 18:16 Khalid Ali
2025-07-15 18:45 ` Nikolay Borisov
2025-07-15 19:05 ` [tip: x86/cleanups] x86/boot: Avoid redundant %cr4 write " tip-bot2 for Khalid Ali
2025-07-15 20:30 ` [PATCH v3] x86/boot: Avoid writing to cr4 twice " H. Peter Anvin
2025-07-15 20:31 ` H. Peter Anvin [this message]
2025-07-15 21:21 ` Andrew Cooper
2025-07-16 1:45 ` Borislav Petkov
2025-07-16 9:07 ` Khalid Ali
2025-07-16 13:27 ` Borislav Petkov
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