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Message-ID: <d66795f8-e524-2912-4b71-92ca4ffe8807@linux.intel.com>
Date:   Mon, 18 Sep 2023 15:51:43 +0800
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Subject: Re: [RFC PATCH v12 11/33] KVM: Introduce per-page memory attributes
To:     Sean Christopherson <seanjc@google.com>
Cc:     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, 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>,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Fuad Tabba <tabba@google.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Anish Moorthy <amoorthy@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        Isaku Yamahata <isaku.yamahata@intel.com>,
        Xu Yilun <yilun.xu@intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Ackerley Tng <ackerleytng@google.com>,
        Maciej Szmigiero <mail@maciej.szmigiero.name>,
        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>
References: <20230914015531.1419405-1-seanjc@google.com>
 <20230914015531.1419405-12-seanjc@google.com>
From:   Binbin Wu <binbin.wu@linux.intel.com>
In-Reply-To: <20230914015531.1419405-12-seanjc@google.com>
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On 9/14/2023 9:55 AM, Sean Christopherson wrote:
> From: Chao Peng <chao.p.peng@linux.intel.com>
[...]
>   
> +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
> +/*
> + * Returns true if _all_ gfns in the range [@start, @end) have attributes
> + * matching @attrs.
> + */
> +bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> +				     unsigned long attrs)
> +{
> +	XA_STATE(xas, &kvm->mem_attr_array, start);
> +	unsigned long index;
> +	bool has_attrs;
> +	void *entry;
> +
> +	rcu_read_lock();
> +
> +	if (!attrs) {
> +		has_attrs = !xas_find(&xas, end);
IIUIC, xas_find() is inclusive for "end", so here should be "end - 1" ?


> +		goto out;
> +	}
> +
> +	has_attrs = true;
> +	for (index = start; index < end; index++) {
> +		do {
> +			entry = xas_next(&xas);
> +		} while (xas_retry(&xas, entry));
> +
> +		if (xas.xa_index != index || xa_to_value(entry) != attrs) {
> +			has_attrs = false;
> +			break;
> +		}
> +	}
> +
> +out:
> +	rcu_read_unlock();
> +	return has_attrs;
> +}
> +
>
[...]