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Tue, 04 Mar 2025 15:24:40 -0800 (PST) X-Google-Smtp-Source: AGHT+IF6MzWOSSNkUTEXlvQ9iJOjQzvGjjEFVSlf2ZUpEyaz6kgQfPIR8TZfY2WcFT4CY7XBnhBEjw== X-Received: by 2002:a05:620a:4c81:b0:7c0:bad7:12b5 with SMTP id af79cd13be357-7c3d8ee13demr168819085a.54.1741130680145; Tue, 04 Mar 2025 15:24:40 -0800 (PST) Received: from x1.local ([85.131.185.92]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c3c3edff13sm266678485a.69.2025.03.04.15.24.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Mar 2025 15:24:39 -0800 (PST) Date: Tue, 4 Mar 2025 18:24:35 -0500 From: Peter Xu To: Ackerley Tng Cc: tabba@google.com, quic_eberman@quicinc.com, roypat@amazon.co.uk, jgg@nvidia.com, david@redhat.com, rientjes@google.com, fvdl@google.com, jthoughton@google.com, seanjc@google.com, pbonzini@redhat.com, zhiquan1.li@intel.com, fan.du@intel.com, jun.miao@intel.com, isaku.yamahata@intel.com, muchun.song@linux.dev, mike.kravetz@oracle.com, erdemaktas@google.com, vannapurve@google.com, qperret@google.com, jhubbard@nvidia.com, willy@infradead.org, shuah@kernel.org, brauner@kernel.org, bfoster@redhat.com, kent.overstreet@linux.dev, pvorel@suse.cz, rppt@kernel.org, richard.weiyang@gmail.com, anup@brainfault.org, haibo1.xu@intel.com, ajones@ventanamicro.com, vkuznets@redhat.com, maciej.wieczor-retman@intel.com, pgonda@google.com, oliver.upton@linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-fsdevel@kvack.org Subject: Re: [RFC PATCH 27/39] KVM: guest_memfd: Allow mmapping guest_memfd files Message-ID: References: <5a05eb947cf7aa21f00b94171ca818cc3d5bdfee.1726009989.git.ackerleytng@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5a05eb947cf7aa21f00b94171ca818cc3d5bdfee.1726009989.git.ackerleytng@google.com> On Tue, Sep 10, 2024 at 11:43:58PM +0000, Ackerley Tng wrote: > @@ -790,6 +791,9 @@ static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len) > */ > filemap_invalidate_lock(inode->i_mapping); > > + /* TODO: Check if even_cows should be 0 or 1 */ > + unmap_mapping_range(inode->i_mapping, start, len, 0); Should be s/start/offset/ here, or should expect some filemap crash assert on non-zero mapcounts (when it starts to matter). Btw, it would be nice if the new version would allow kvm to be compiled as a module. Currently it uses a lot of mm functions that are not yet exported, so AFAIU it will only build if kvm is builtin. Thanks, -- Peter Xu