linux-kernel - Re: [PATCH] x86/kvm: Override default caching mode for SEV-SNP and TDX

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: <sr2au3c5me6nexco46sqmld25nxonpg4ry3vf7ody5yw6dyjpc@m77cc2nnksdp>
Date: Tue, 15 Oct 2024 16:54:19 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Dave Hansen <dave.hansen@...el.com>
Cc: Jürgen Groß <jgross@...e.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, Vitaly Kuznetsov <vkuznets@...hat.com>, 
	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>, 
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org, Binbin Wu <binbin.wu@...el.com>, 
	Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH] x86/kvm: Override default caching mode for SEV-SNP and
 TDX

On Tue, Oct 15, 2024 at 06:14:29AM -0700, Dave Hansen wrote:
> On 10/15/24 03:12, Jürgen Groß wrote:
> >>
> >> +    /* Set WB as the default cache mode for SEV-SNP and TDX */
> >> +    mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
> > 
> > Do you really want to do this for _all_ KVM guests?
> > 
> > I'd expect this call to be conditional on TDX or SEV-SNP.
> 
> I was confused by this as well.
> 
> Shouldn't mtrr_overwrite_state() be named something more like:
> 
> 	guest_force_mtrr_state()
> 
> or something?
> 
> The mtrr_overwrite_state() comment is pretty good, but it looks quite
> confusing from the caller.

I can submit a following up patch with rename if it is fine.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov