linux-kernel - Re: [PATCH] x86: kvm: use alternatives for VMCALL vs. VMMCALL if kernel text is read-only

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Message-ID: <20140923082728.GC22072@pd.tnic>
Date:	Tue, 23 Sep 2014 10:27:28 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Paolo Bonzini <pbonzini@...hat.com>
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	chris@...chsys.com, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	Borislav Petkov <bp@...e.de>
Subject: Re: [PATCH] x86: kvm: use alternatives for VMCALL vs. VMMCALL if
 kernel text is read-only

On Tue, Sep 23, 2014 at 10:00:12AM +0200, Paolo Bonzini wrote:
> Il 22/09/2014 21:43, Borislav Petkov ha scritto:
> >> > On x86_64, kernel text mappings are mapped read-only with CONFIG_DEBUG_RODATA.
> > Hmm, that depends on DEBUG_KERNEL.
> > 
> > I think you're actually talking about distro kernels which enable
> > CONFIG_DEBUG_RODATA, right?
> 
> This is for guest kernels, so it's not necessarily distro kernels.
> Anyone who compiles their kernel with CONFIG_DEBUG_RODATA + PV spinlocks
> would not be able to run it on AMD.

I see. Yeah, so the patch makes sense to me:

Acked-by: Borislav Petkov <bp@...e.de>

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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