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Wed, 31 Jul 2024 03:12:39 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG5PK2N6SVlp21V74v51wpDQW38LtkY7BoBaQqhGgHQsZ4igHg8AC/1gwfVPPR89SMfLALrEQ== X-Received: by 2002:a17:906:d26a:b0:a7a:c256:3c5 with SMTP id a640c23a62f3a-a7d40161c68mr868863766b.46.1722420759395; Wed, 31 Jul 2024 03:12:39 -0700 (PDT) Received: from [192.168.10.81] ([151.95.101.29]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-a7acad41164sm746659566b.102.2024.07.31.03.12.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 31 Jul 2024 03:12:38 -0700 (PDT) Message-ID: <10429875-b9a1-4454-b54a-1c3be5630771@redhat.com> Date: Wed, 31 Jul 2024 12:12:37 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v12 45/84] KVM: guest_memfd: Provide "struct page" as output from kvm_gmem_get_pfn() To: Sean Christopherson References: <20240726235234.228822-1-seanjc@google.com> <20240726235234.228822-46-seanjc@google.com> <2da6b57e-d5c2-4016-b89b-d51700eeb845@redhat.com> From: Paolo Bonzini Autocrypt: addr=pbonzini@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, David Matlack , linux-riscv@lists.infradead.org, Claudio Imbrenda , Marc Zyngier , Janosch Frank , Huacai Chen , Christian Borntraeger , Albert Ou , Bibo Mao , loongarch@lists.linux.dev, Paul Walmsley , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Oliver Upton , Palmer Dabbelt , David Stevens , kvm-riscv@lists.infradead.org, Anup Patel , Tianrui Zhao , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 7/30/24 22:00, Sean Christopherson wrote: > The probability of guest_memfd not having struct page for mapped pfns is likely > very low, but at the same time, providing a pfn+page pair doesn't cost us much. > And if it turns out that not having struct page is nonsensical, deferring the > kvm_gmem_get_pfn() => kvm_gmem_get_page() conversion could be annoying, but highly > unlikely to be painful since it should be 100% mechanical. Whereas reverting back > to kvm_gmem_get_pfn() if we make the wrong decision now could mean doing surgery > on a pile of arch code. Ok, fair enough. The conflict resolution is trivial either way (I also checked the TDX series and miraculously it has only one conflict which is also trivial). Paolo