Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 2/6] KVM: mmu: also return page from gfn_to_pfn
To:     Nicholas Piggin <npiggin@gmail.com>,
        Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Marc Zyngier <maz@kernel.org>,
        Paul Mackerras <paulus@ozlabs.org>,
        David Stevens <stevensd@chromium.org>,
        Zhenyu Wang <zhenyuw@linux.intel.com>,
        Zhi Wang <zhi.a.wang@intel.com>
Cc:     Alexandru Elisei <alexandru.elisei@arm.com>,
        dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
        intel-gvt-dev@lists.freedesktop.org,
        James Morse <james.morse@arm.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, kvmarm@lists.cs.columbia.edu,
        kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        Sean Christopherson <seanjc@google.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Will Deacon <will@kernel.org>
References: <20210624035749.4054934-1-stevensd@google.com>
 <20210624035749.4054934-3-stevensd@google.com>
 <1624524331.zsin3qejl9.astroid@bobo.none>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <201b68a7-10ea-d656-0c1e-5511b1f22674@redhat.com>
Date:   Thu, 24 Jun 2021 11:42:33 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.1
MIME-Version: 1.0
In-Reply-To: <1624524331.zsin3qejl9.astroid@bobo.none>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 24/06/21 10:52, Nicholas Piggin wrote:
>> For now, wrap all calls to gfn_to_pfn functions in the new helper
>> function. Callers which don't need the page struct will be updated in
>> follow-up patches.
> Hmm. You mean callers that do need the page will be updated? Normally
> if there will be leftover users that don't need the struct page then
> you would go the other way and keep the old call the same, and add a new
> one (gfn_to_pfn_page) just for those that need it.

Needing kvm_pfn_page_unwrap is a sign that something might be buggy, so 
it's a good idea to move the short name to the common case and the ugly 
kvm_pfn_page_unwrap(gfn_to_pfn(...)) for the weird one.  In fact I'm not 
sure there should be any kvm_pfn_page_unwrap in the end.

Paolo