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[34.168.104.7]) by smtp.gmail.com with ESMTPSA id l8-20020a17090a49c800b0022bae5c3e1esm148419pjm.9.2023.01.24.16.20.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Jan 2023 16:20:29 -0800 (PST) Date: Wed, 25 Jan 2023 00:20:26 +0000 From: Sean Christopherson To: Liam Merwick Cc: Chao Peng , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Arnd Bergmann , Naoya Horiguchi , Miaohe Lin , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , tabba@google.com, Michael Roth , mhocko@suse.com, wei.w.wang@intel.com Subject: Re: [PATCH v10 0/9] KVM: mm: fd-based approach for supporting KVM Message-ID: References: <20221202061347.1070246-1-chao.p.peng@linux.intel.com> <48953bf2-cee9-f818-dc50-5fb5b9b410bf@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48953bf2-cee9-f818-dc50-5fb5b9b410bf@oracle.com> X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: 1ou6uiu3dt4xyzrsps6ct5qi3amompwe X-Rspamd-Queue-Id: A915320002 X-HE-Tag: 1674606031-172726 X-HE-Meta: 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 O0VMvlBA xoaTXE3RQ4Ipu7prQ9XV2wpuK0BtCh7ilLQFxxgu0PlJSH/NvHaB0G1l9Z3lD2HMjoURNMTbrjcV37jX4prgYWLNHqfTl8dwWJcXcSmE6iajb+3Ob8/pTFhkMml5qwEzhAxNwUyHkW4eb6blNWJaYjAMUExpA4BsqolqmPAuW2o46Z0z7GDxumu7TvKrQ2zI3VIrxp2oISwZBIG0E1F58Njs4l1cVuzHbVD+3KFFhWorSjakipNHFKYQIcaK0p4pU3Gll3a/MQKfzyQC9Jw7mzJwKTxjdg4L57kKNysVg9CEqWq3Uss6i6bmwXFXc2vXKPgVTIr6eVH+xPN8IJ95HYamVl0K1P4iZXw1vmJXWNS0Vreh8aT/vaRypnGzupqjzZ4svSiGF9bnbxunUbyQkV3Yw2g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jan 24, 2023, Liam Merwick wrote: > On 14/01/2023 00:37, Sean Christopherson wrote: > > On Fri, Dec 02, 2022, Chao Peng wrote: > > > This patch series implements KVM guest private memory for confidential > > > computing scenarios like Intel TDX[1]. If a TDX host accesses > > > TDX-protected guest memory, machine check can happen which can further > > > crash the running host system, this is terrible for multi-tenant > > > configurations. The host accesses include those from KVM userspace like > > > QEMU. This series addresses KVM userspace induced crash by introducing > > > new mm and KVM interfaces so KVM userspace can still manage guest memory > > > via a fd-based approach, but it can never access the guest memory > > > content. > > > > > > The patch series touches both core mm and KVM code. I appreciate > > > Andrew/Hugh and Paolo/Sean can review and pick these patches. Any other > > > reviews are always welcome. > > > - 01: mm change, target for mm tree > > > - 02-09: KVM change, target for KVM tree > > > > A version with all of my feedback, plus reworked versions of Vishal's selftest, > > is available here: > > > > git@github.com:sean-jc/linux.git x86/upm_base_support > > > > It compiles and passes the selftest, but it's otherwise barely tested. There are > > a few todos (2 I think?) and many of the commits need changelogs, i.e. it's still > > a WIP. > > > > When running LTP (https://github.com/linux-test-project/ltp) on the v10 > bits (and also with Sean's branch above) I encounter the following NULL > pointer dereference with testcases/kernel/syscalls/madvise/madvise01 > (100% reproducible). > > It appears that in restrictedmem_error_page() inode->i_mapping->private_data > is NULL > in the list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) > but I don't know why. Kirill, can you take a look? Or pass the buck to someone who can? :-)