Re: [RFCv1 2/7] x86/kvm: Introduce KVM memory protection feature

From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Sean Christopherson <seanjc@google.com>,
	Jim Mattson <jmattson@google.com>,
	David Rientjes <rientjes@google.com>,
	"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	"Kleen, Andi" <andi.kleen@intel.com>,
	"Yamahata, Isaku" <isaku.yamahata@intel.com>,
	x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFCv1 2/7] x86/kvm: Introduce KVM memory protection feature
Date: Fri, 9 Apr 2021 16:36:01 +0300	[thread overview]
Message-ID: <20210409133601.2qepfc77stujulhf@box> (raw)
In-Reply-To: <20210408095235.GH10192@zn.tnic>

On Thu, Apr 08, 2021 at 11:52:35AM +0200, Borislav Petkov wrote:
> On Fri, Apr 02, 2021 at 06:26:40PM +0300, Kirill A. Shutemov wrote:
> > Provide basic helpers, KVM_FEATURE, CPUID flag and a hypercall.
> > 
> > Host side doesn't provide the feature yet, so it is a dead code for now.
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> >  arch/x86/include/asm/cpufeatures.h   |  1 +
> >  arch/x86/include/asm/kvm_para.h      |  5 +++++
> >  arch/x86/include/uapi/asm/kvm_para.h |  3 ++-
> >  arch/x86/kernel/kvm.c                | 18 ++++++++++++++++++
> >  include/uapi/linux/kvm_para.h        |  3 ++-
> >  5 files changed, 28 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> > index 84b887825f12..5b6f23e6edc4 100644
> > --- a/arch/x86/include/asm/cpufeatures.h
> > +++ b/arch/x86/include/asm/cpufeatures.h
> > @@ -238,6 +238,7 @@
> >  #define X86_FEATURE_VMW_VMMCALL		( 8*32+19) /* "" VMware prefers VMMCALL hypercall instruction */
> >  #define X86_FEATURE_SEV_ES		( 8*32+20) /* AMD Secure Encrypted Virtualization - Encrypted State */
> >  #define X86_FEATURE_VM_PAGE_FLUSH	( 8*32+21) /* "" VM Page Flush MSR is supported */
> > +#define X86_FEATURE_KVM_MEM_PROTECTED	( 8*32+22) /* KVM memory protection extenstion */
> 										    ^^^^^^^^^^
> What's that feature bit for?

The patchset is still in path-finding stage. I'll be more specific once we
settle on how the feature works.

> Also, use a spellchecker pls: "extenstion".

Ouch. Thanks.

-- 
 Kirill A. Shutemov