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From: Dave Hansen <dave.hansen@intel.com>
To: David Woodhouse <dwmw2@infradead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	"Eric Biederman" <ebiederm@xmission.com>,
	"Sourabh Jain" <sourabhjain@linux.ibm.com>,
	"Hari Bathini" <hbathini@linux.ibm.com>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Baoquan He" <bhe@redhat.com>, "Yuntao Wang" <ytcoode@gmail.com>,
	"David Kaplan" <david.kaplan@amd.com>,
	"Tao Liu" <ltao@redhat.com>, "Kai Huang" <kai.huang@intel.com>,
	"Ard Biesheuvel" <ardb@kernel.org>,
	"Josh Poimboeuf" <jpoimboe@kernel.org>,
	"Breno Leitao" <leitao@debian.org>,
	"Wei Yang" <richard.weiyang@gmail.com>,
	"Rong Xu" <xur@google.com>,
	"Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
	linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
	"Simon Horman" <horms@kernel.org>,
	"Dave Young" <dyoung@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	bsz@amazon.de, nathan@kernel.org
Subject: Re: [EXTERNAL] [PATCH 1/9] x86/kexec: Disable global pages before writing to control page
Date: Tue, 17 Dec 2024 07:06:03 -0800	[thread overview]
Message-ID: <ca888eb1-056c-436e-9471-91dbf2f6abf4@intel.com> (raw)
In-Reply-To: <7593b839a8c7d3122e08660ca2e957d834665005.camel@infradead.org>

On 12/17/24 06:56, David Woodhouse wrote:
>> Anyway, I think we can leave the belt-and-suspenders programming in this
>> case. A comment wouldn't hurt I guess.
> I'm a little lost. In this case I don't see belt-and-suspenders
> programming. We're not loading CR3 after clearing CR4.PGE just to be
> paranoid about making really really sure the TLB is flushed.
> 
> We're loading CR3 because we're switching from the kernel's page tables
> to the new identity mapping set up for the relocate_kernel environment.

Yes, agreed, that's another reason the CR3 write must stay. I hadn't
even considered that part yet honestly.

  reply	other threads:[~2024-12-17 15:06 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-16 23:24 [PATCH 0/9] x86/kexec: Fixes for tip/x86/boot David Woodhouse
2024-12-16 23:24 ` [PATCH 1/9] x86/kexec: Disable global pages before writing to control page David Woodhouse
2024-12-17 12:25   ` Kirill A. Shutemov
2024-12-17 12:39     ` David Woodhouse
2024-12-17 14:51     ` Dave Hansen
2024-12-17 14:56       ` [EXTERNAL] " David Woodhouse
2024-12-17 15:06         ` Dave Hansen [this message]
2024-12-16 23:24 ` [PATCH 2/9] x86/kexec: Ensure preserve_context flag is set on return to kernel David Woodhouse
2024-12-17 16:38   ` Uros Bizjak
2025-01-03 10:14     ` David Woodhouse
2024-12-16 23:24 ` [PATCH 3/9] x86/kexec: Use correct swap page in swap_pages function David Woodhouse
2024-12-16 23:24 ` [PATCH 4/9] x86/kexec: Fix stack and handling of re-entry point for ::preserve_context David Woodhouse
2024-12-16 23:24 ` [PATCH 5/9] x86/kexec: Fix location of relocate_kernel with -ffunction-sections David Woodhouse
2024-12-16 23:24 ` [PATCH 6/9] x86/kexec: Mark machine_kexec() with __nocfi David Woodhouse
2024-12-16 23:24 ` [PATCH 7/9] kexec_core: Add and update comments regarding the KEXEC_JUMP flow David Woodhouse
2025-01-03  9:24   ` Dave Young
2025-01-03 10:14     ` David Woodhouse
2024-12-16 23:24 ` [PATCH 8/9] x86/kexec: Cope with relocate_kernel() not being at the start of the page David Woodhouse
2024-12-17  8:47   ` Ard Biesheuvel
2024-12-17  9:17     ` David Woodhouse
2024-12-17  9:25       ` Ard Biesheuvel
2024-12-17  9:36         ` David Woodhouse
2025-01-03 10:10         ` David Woodhouse
2025-01-06 16:09           ` Ard Biesheuvel
2025-01-06 16:13             ` David Woodhouse
2025-01-06 16:27               ` Ard Biesheuvel
2024-12-16 23:24 ` [PATCH 9/9] x86/kexec: Use typedef for relocate_kernel_fn function prototype David Woodhouse
2024-12-17  8:49   ` Ard Biesheuvel
2024-12-17  9:21     ` David Woodhouse
2024-12-17  9:29       ` Ard Biesheuvel
2024-12-17  9:42         ` David Woodhouse
2024-12-17  9:54           ` Ard Biesheuvel
2024-12-17 10:06             ` David Woodhouse
2024-12-17 10:14               ` Ard Biesheuvel
2024-12-17 10:47                 ` David Woodhouse
2024-12-17 10:29             ` David Woodhouse
2024-12-26  8:38 ` [PATCH 0/9] x86/kexec: Fixes for tip/x86/boot David Woodhouse

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