linux-kernel - Re: [PATCH 1/4] x86/coco: Add a new CC attribute to unify cache flush during kexec

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Date: Wed, 28 Feb 2024 12:02:07 +0100
From: Borislav Petkov <bp@...en8.de>
To: "Huang, Kai" <kai.huang@...el.com>
Cc: "dyoung@...hat.com" <dyoung@...hat.com>,
	"Gao, Chao" <chao.gao@...el.com>,
	"luto@...nel.org" <luto@...nel.org>,
	"Hansen, Dave" <dave.hansen@...el.com>,
	"x86@...nel.org" <x86@...nel.org>,
	"bhe@...hat.com" <bhe@...hat.com>,
	"peterz@...radead.org" <peterz@...radead.org>,
	"hpa@...or.com" <hpa@...or.com>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"thomas.lendacky@....com" <thomas.lendacky@....com>,
	"kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"nik.borisov@...e.com" <nik.borisov@...e.com>,
	"pbonzini@...hat.com" <pbonzini@...hat.com>
Subject: Re: [PATCH 1/4] x86/coco: Add a new CC attribute to unify cache
 flush during kexec

On Wed, Feb 28, 2024 at 09:21:00AM +0000, Huang, Kai wrote:
> Based on this I'll change to do unconditional WBINVD during kexec() for in
> stop_this_cpu() and relocate_kernel().  Please let me know if you have any
> comments.

Yes, pls make sure to summarize in the commit message what this thread
figured out. But basically, we want to try the simple approach and
WBINVD unconditionally on the CPU stopping path so that caches are clean
and there's no potential issues...

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette