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Date:   Thu, 20 Jul 2023 13:20:11 -0700
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Subject: Re: [RFC PATCH v11 08/29] KVM: Introduce per-page memory attributes
From:   Sean Christopherson <seanjc@google.com>
To:     Isaku Yamahata <isaku.yamahata@gmail.com>
Cc:     Yuan Yao <yuan.yao@linux.intel.com>,
        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,
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        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>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
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On Thu, Jul 20, 2023, Isaku Yamahata wrote:
> On Thu, Jul 20, 2023 at 04:09:12PM +0800,
> Yuan Yao <yuan.yao@linux.intel.com> wrote:
> 
> > On Tue, Jul 18, 2023 at 04:44:51PM -0700, Sean Christopherson wrote:
> > > @@ -2301,4 +2305,14 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr)
> > >  /* Max number of entries allowed for each kvm dirty ring */
> > >  #define  KVM_DIRTY_RING_MAX_ENTRIES  65536
> > >
> > > +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
> > > +static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
> > > +{
> > > +	return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
> > > +}
> > > +
> > > +bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
> > > +					 struct kvm_gfn_range *range);
> > 
> > Used but no definition in this patch, it's defined in next patch 09.
> > How about add weak version in this patch and let ARCHs to overide it ?
> 
> It is guarded by CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES.

Yep.  I don't love the ordering, e.g. this patch can't even be compile tested
until later in the series, but I wanted to separate x86 usage from the generic
support code.