linux-kernel - Re: [PATCH v5 5/8] x86/sev: Map only the RMP table entries instead of the full RMP range

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Message-ID: <20241104062845.GPZyhpnWueB-jCEl2H@fat_crate.local>
Date: Mon, 4 Nov 2024 07:28:45 +0100
From: Borislav Petkov <bp@...en8.de>
To: Tom Lendacky <thomas.lendacky@....com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Michael Roth <michael.roth@....com>,
	Ashish Kalra <ashish.kalra@....com>,
	Nikunj A Dadhania <nikunj@....com>,
	Neeraj Upadhyay <Neeraj.Upadhyay@....com>
Subject: Re: [PATCH v5 5/8] x86/sev: Map only the RMP table entries instead
 of the full RMP range

On Mon, Oct 28, 2024 at 02:32:40PM -0500, Tom Lendacky wrote:
> @@ -224,7 +246,14 @@ static int __init snp_rmptable_init(void)
>  	if (val & MSR_AMD64_SYSCFG_SNP_EN)
>  		goto skip_enable;
>  
> -	memset(rmptable_start, 0, probed_rmp_size);
> +	/* Zero out the RMP bookkeeping area */
> +	if (!init_rmptable_bookkeeping()) {

So let's call it what it is then:

diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c
index 5871c924c0b2..8145a7b14fa2 100644
--- a/arch/x86/virt/svm/sev.c
+++ b/arch/x86/virt/svm/sev.c
@@ -173,7 +173,7 @@ void __init snp_fixup_e820_tables(void)
 	__snp_fixup_e820_tables(probed_rmp_base + probed_rmp_size);
 }
 
-static bool __init init_rmptable_bookkeeping(void)
+static bool __init clear_rmptable_bookkeeping(void)
 {
 	void *bk;
 
@@ -246,8 +246,7 @@ static int __init snp_rmptable_init(void)
 	if (val & MSR_AMD64_SYSCFG_SNP_EN)
 		goto skip_enable;
 
-	/* Zero out the RMP bookkeeping area */
-	if (!init_rmptable_bookkeeping()) {
+	if (!clear_rmptable_bookkeeping()) {
 		memunmap(rmptable_start);
 		goto nosnp;
 	}


-- 
Regards/Gruss,
    Boris.

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