Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 27 Jul 2023 11:24:22 +0800
From:   Xu Yilun <yilun.xu@intel.com>
To:     Sean Christopherson <seanjc@google.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>, Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        Huacai Chen <chenhuacai@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Anup Patel <anup@brainfault.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Paul Moore <paul@paul-moore.com>,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>, kvm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Fuad Tabba <tabba@google.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        Vishal Annapurve <vannapurve@google.com>,
        Ackerley Tng <ackerleytng@google.com>,
        Maciej Szmigiero <mail@maciej.szmigiero.name>,
        Vlastimil Babka <vbabka@suse.cz>,
        David Hildenbrand <david@redhat.com>,
        Quentin Perret <qperret@google.com>,
        Michael Roth <michael.roth@amd.com>,
        Wang <wei.w.wang@intel.com>,
        Liam Merwick <liam.merwick@oracle.com>,
        Isaku Yamahata <isaku.yamahata@gmail.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFC PATCH v11 08/29] KVM: Introduce per-page memory attributes
Message-ID: <ZMHjZvcmzxMhTyM3@yilunxu-OptiPlex-7050>
References: <20230718234512.1690985-1-seanjc@google.com>
 <20230718234512.1690985-9-seanjc@google.com>
 <ZL4BiQWihfrD0TOJ@yilunxu-OptiPlex-7050>
 <ZMFC+V6Llv1JWLEt@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZMFC+V6Llv1JWLEt@google.com>
Precedence: bulk

On 2023-07-26 at 08:59:53 -0700, Sean Christopherson wrote:
> On Mon, Jul 24, 2023, Xu Yilun wrote:
> > On 2023-07-18 at 16:44:51 -0700, Sean Christopherson wrote:
> > > +	if (WARN_ON_ONCE(start == end))
> > > +		return -EINVAL;
> > 
> > Also, is this check possible to be hit? Maybe remove it?
> 
> It should be impossible to, hence the WARN.  I added the check for two reasons:
> (1) to help document that end is exclusive, and (2) to guard against future bugs.

Understood. I'm good to it.