linux-kernel - Re: [PATCH v16 05/13] x86/sev: Add Secure TSC support for SNP guests

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250107123711.GEZ30f9_OzOcJSF10o@fat_crate.local>
Date: Tue, 7 Jan 2025 13:37:11 +0100
From: Borislav Petkov <bp@...en8.de>
To: "Nikunj A. Dadhania" <nikunj@....com>
Cc: linux-kernel@...r.kernel.org, thomas.lendacky@....com, x86@...nel.org,
	kvm@...r.kernel.org, mingo@...hat.com, tglx@...utronix.de,
	dave.hansen@...ux.intel.com, pgonda@...gle.com, seanjc@...gle.com,
	pbonzini@...hat.com, francescolavra.fl@...il.com
Subject: Re: [PATCH v16 05/13] x86/sev: Add Secure TSC support for SNP guests

On Tue, Jan 07, 2025 at 05:13:03PM +0530, Nikunj A. Dadhania wrote:
> >> +	case CC_ATTR_GUEST_SNP_SECURE_TSC:
> >> +		return (sev_status & MSR_AMD64_SEV_SNP_ENABLED) &&
> > 
> > This is new here?
> 
> Yes, this was suggested by Tom here [1]

Either of you care to explain why this is needed?

> >> +			(sev_status & MSR_AMD64_SNP_SECURE_TSC);

I would strongly assume that whatever sets MSR_AMD64_SNP_SECURE_TSC will have
checked/set MSR_AMD64_SEV_SNP_ENABLED already.

-- 
Regards/Gruss,
    Boris.

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