linux-kernel - Re: [PATCH] x86/sev: Apply RMP table fixups for kexec.

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Message-ID: <20240402202118.GCZgxovu-pgPKYvner@fat_crate.local>
Date: Tue, 2 Apr 2024 22:21:18 +0200
From: Borislav Petkov <bp@...en8.de>
To: "Kalra, Ashish" <ashish.kalra@....com>
Cc: bp@...nel.org, thomas.lendacky@....com, linux-kernel@...r.kernel.org,
	linux-tip-commits@...r.kernel.org, michael.roth@....com,
	x86@...nel.org
Subject: Re: [PATCH] x86/sev: Apply RMP table fixups for kexec.

On Tue, Apr 02, 2024 at 02:33:44PM -0500, Kalra, Ashish wrote:
> And we can't do this in snp_rmptable_init() as e820_table_firmware can't be
> fixed at that point and by that time this table has been mapped into sysfs
> (/sys/firmware) which is used by kexec -c variant.

Well, you have to do something here because if snp_rmptable_init()
late-disables SNP, your RMP table fixups are moot and invalid.

Which means, your RMP table fixups need to happen at the *very* *late*
step after we know that SNP is enabled and won't get disabled anymore.

I.e., in snp_rmptable_init().

-- 
Regards/Gruss,
    Boris.

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