linux-kernel - Re: [PATCH v1 3/3] x86/msr: Convert a native_wrmsr() use to native

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: <aCg27zLhBM5d0dAI@gmail.com>
Date: Sat, 17 May 2025 09:12:47 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Xin Li <xin@...or.com>
Cc: linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
	linux-acpi@...r.kernel.org, tglx@...utronix.de, bp@...en8.de,
	dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
	peterz@...radead.org, jgross@...e.com, boris.ostrovsky@...cle.com,
	rafael@...nel.org, lenb@...nel.org
Subject: Re: [PATCH v1 3/3] x86/msr: Convert a native_wrmsr() use to
 native_wrmsrq()


* Xin Li <xin@...or.com> wrote:

> On 5/15/2025 10:54 AM, Xin Li wrote:
> > On 5/15/2025 8:27 AM, Ingo Molnar wrote:
> > > 
> > > * Xin Li (Intel) <xin@...or.com> wrote:
> > > 
> > > > Convert a native_wrmsr() use to native_wrmsrq() to zap meaningless type
> > > > conversions when a u64 MSR value is splitted into two u32.
> > > > 
> > > 
> > > BTW., at this point we should probably just replace
> > > sev_es_wr_ghcb_msr() calls with direct calls to:
> > > 
> > >     native_wrmsrq(MSR_AMD64_SEV_ES_GHCB, ...);
> > > 
> > > as sev_es_wr_ghcb_msr() is now basically an open-coded native_wrmsrq().
> > > 
> > 
> > I thought about it, however it looks to me that current code prefers not
> > to spread MSR_AMD64_SEV_ES_GHCB in 17 callsites.  And anyway it's a
> > __always_inline function.
> > 
> > But as you have asked, I will make the change unless someone objects.
> 
> Hi Ingo,
> 
> I took a further look and found that we can't simply replace
> sev_es_wr_ghcb_msr() with native_wrmsrq(MSR_AMD64_SEV_ES_GHCB, ...).
> 
> There are two sev_es_wr_ghcb_msr() definitions.  One is defined in
> arch/x86/boot/compressed/sev.h and it references boot_wrmsr() defined in
> arch/x86/boot/msr.h to do MSR write.

Ah, indeed, it's also a startup code wrapper, which wrmsrq() doesn't 
have at the moment. Fair enough.

Thanks,

	Ingo