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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> MIME-Version: 1.0 In-Reply-To: <5a05eb947cf7aa21f00b94171ca818cc3d5bdfee.1726009989.git.ackerleytng@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: hlvoWwy_Oz40W9ypRBj0AIt5ksct-HkbeULH8ggVVzw_1741130680 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: A754F20002 X-Stat-Signature: bau7m1r676tgor4nffzoox3c9addeof9 X-HE-Tag: 1741130687-298610 X-HE-Meta: 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 +Bj5BrMU zY2Ev/BET+ze0Klcu7BkO2wxRbhnS8BE8c94K1kozQyfYB/B/gzpuYpVuZP/u9Y0EWQVHeUXEmoB9+5YYTWpCdwSKqyHUXyztNAEggHNWWIOvcR4HSt09SMn5TA6HueWOnGIjV5eGWw/thtiFUvHAWeKcO2HmRD0yIJknyLALQbDaUoMDRU1WdgnAQyJpzOL1tWSowYulN4kfoZU+Zxn3YSMUmTTzw1TRusqAghvkCwV8O1w10fJbXmPpW9wk6Zr829eEHQhUhDncF7DQkV4rKUMgdTmbKZXspih2QGI0Au3wUltRb5MaPEMIryfAyWkAvm32fjFPWO3FmOlVHr0Zg3O97mRAnfIjgBWnvB4HIoXVaGLwZWLaPxL7CqgnFGp3aVczVgNBsq4WqKucv17ApqH2CYmpVPYQr3Il87H0QrCwKHYDzVKc1eMo/4Rzu1LDPkE3 X-Bogosity: Ham, tests=bogofilter, spamicity=0.219049, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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