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AJvYcCUSfyMCZJORNhM13QvyfHNRit0/F9SxVDXs5kbmLBS+WdYRwslpCw1Us6X/ogEi++zYZ0IjzDW2/w==@kvack.org X-Gm-Message-State: AOJu0YyWPecnc6k/hj5VBzF1Q5to9yAIF/+DYPgjrP3flWglW0RGihkx XkO82BCz8RxobxdU6wAlOmmq+vymqiJbJ5oCO5QQEDh9sVlkc02UsHwL+N5YtpYjGqaUQ0S2dQ= = X-Google-Smtp-Source: AGHT+IFGcHNmqPkBkdOHisoptvfjVPA8qQ1v9Rp7boCnFq0xHETF9YJ177CDOBi8Rw9nEFkENUVOukdolg== X-Received: from wmqc13.prod.google.com ([2002:a05:600c:a4d:b0:434:a050:ddcf]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4f55:b0:434:a746:9c82 with SMTP id 5b1f17b1804b1-438dc3aa6c4mr38042595e9.5.1738171402339; Wed, 29 Jan 2025 09:23:22 -0800 (PST) Date: Wed, 29 Jan 2025 17:23:09 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.48.1.262.g85cc9f2d1e-goog Message-ID: <20250129172320.950523-1-tabba@google.com> Subject: [RFC PATCH v2 00/11] KVM: Mapping guest_memfd backed memory at the host for software protected VMs From: Fuad Tabba To: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, yu.c.zhang@linux.intel.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, tabba@google.com X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: ED5B912000B X-Stat-Signature: q3twjt7ckhmxjom544syjwbks6gwof6o X-Rspam-User: X-HE-Tag: 1738171403-350729 X-HE-Meta: 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 n8Du5fRR 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 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: List-Subscribe: List-Unsubscribe: Main changes since v1 [1]: - Added x86 support for mapping guest_memfd at the host, enabled only for the KVM_X86_SW_PROTECTED_VM type. - Require setting memslot userspace_addr for guest_memfd slots even if shared, and remove patches that worked around that. - Brought in more of the infrastructure from the patch series that allows restricted mapping of guest_memfd backed memory. - Renamed references to "mappable" -> "shared". - Expanded the selftests. - Added instructions to test on x86 and arm64 (below). - Rebased on Linux 6.13. The purpose of this series is to serve as a base for _restricted_ mmap() support for guest_memfd backed memory at the host [2]. It would allow experimentation with what that support would be like in the safe environment of the software VM types, which are meant for testing and experimentation. This series adds a new VM type for arm64, KVM_VM_TYPE_ARM_SW_PROTECTED, analogous to the x86 KVM_X86_SW_PROTECTED_VM. This type is to serve as a development and testing vehicle for Confidential (CoCo) VMs. Similar to its x86 counterpart, SW_PROTECTED is meant only for development and testing. It's not meant to be used for "real" VMs, and especially not in production. The behavior and effective ABI for software-protected VMs is unstable. This series enables mmap() and fault() support for guest_memfd backed memory specifically for the software-protected VM types (in x86 and arm64), only when explicitly enabled in the config. The series is based on Linux 6.13 and much of the code within is a subset of the latest series I sent [2], with the addition of the new software protected vm type. To test this series, I've pushed a kvmtool branch with support for guest_memfd for x86 and arm64 and the new runtime options of --guest_memfd and --sw_protected, which marks the VM as software protected [3]. I plan on upstreaming this branch once I've tested it more and tidied it up a bit (or a lot). To test this patch series on x86 (I use a standard Debian image): Build: - Build the kernel with the following config options enabled: defconfigs: x86_64_defconfig kvm_guest.config config options: KVM KVM_INTEL KVM_PRIVATE_MEM KVM_SW_PROTECTED_VM KVM_GMEM_SHARED_MEM - Build the kernel kvm selftest tools/testing/selftests/kvm, you only need guest_memfd_test, e.g.: make EXTRA_CFLAGS="-static -DDEBUG" -C tools/testing/selftests/kvm - Build kvmtool [3] lkvm-static (I build it on a different machine). make lkvm-static Run: Boot your Linux image with the kernel you built above. The selftest you can run as it is: ./guest_memfd_test For kvmtool, where bzImage is the same as the host's: ./lkvm-static run -c 2 -m 512 -p "break=mount" --kernel bzImage --debug --guest_memfd --sw_protected To test this patch series on arm64 (I use a standard Debian image): Build: - Build the kernel with defconfig - Build the kernel kvm selftest tools/testing/selftests/kvm, you only need guest_memfd_test. - Build kvmtool [3] lkvm-static (I cross compile it on a different machine). You are likely to need libfdt as well. For libfdt (in the same directory as kvmtool): git clone git://git.kernel.org/pub/scm/utils/dtc/dtc.git cd dtc export CC=aarch64-linux-gnu-gcc make cd .. Then for kvmtool: make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- LIBFDT_DIR=./dtc/libfdt/ lkvm-static Run: Boot your Linux image with the kernel you built above. The selftest you can run as it is: ./guest_memfd_test For kvmtool, where Image is the same as the host's, and rootfs is your rootfs image (in case kvmtool can't figure it out): ./lkvm-static run -c 2 -m 512 -d rootfs --kernel Image --force-pci --irqchip gicv3 --debug --guest_memfd --sw_protected You can find (potentially slightly outdated) instructions on how to a full arm64 system stack under QEMU here [4]. Cheers, /fuad [1] https://lore.kernel.org/all/20250122152738.1173160-1-tabba@google.com/ [2] https://lore.kernel.org/all/20250117163001.2326672-1-tabba@google.com/ [3] https://android-kvm.googlesource.com/kvmtool/+/refs/heads/tabba/guestmem-6.13 [4] https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/docs/qemu/qemu-arm64-howto.html Fuad Tabba (11): mm: Consolidate freeing of typed folios on final folio_put() KVM: guest_memfd: Handle final folio_put() of guest_memfd pages KVM: guest_memfd: Allow host to map guest_memfd() pages KVM: guest_memfd: Add KVM capability to check if guest_memfd is shared KVM: guest_memfd: Handle in-place shared memory as guest_memfd backed memory KVM: x86: Mark KVM_X86_SW_PROTECTED_VM as supporting guest_memfd shared memory KVM: arm64: Refactor user_mem_abort() calculation of force_pte KVM: arm64: Handle guest_memfd()-backed guest page faults KVM: arm64: Introduce KVM_VM_TYPE_ARM_SW_PROTECTED machine type KVM: arm64: Enable mapping guest_memfd in arm64 KVM: guest_memfd: selftests: guest_memfd mmap() test when mapping is allowed Documentation/virt/kvm/api.rst | 5 + arch/arm64/include/asm/kvm_host.h | 10 ++ arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/arm.c | 5 + arch/arm64/kvm/mmu.c | 91 ++++++++++++------- arch/x86/include/asm/kvm_host.h | 5 + arch/x86/kvm/Kconfig | 3 +- include/linux/kvm_host.h | 19 +++- include/linux/page-flags.h | 22 +++++ include/uapi/linux/kvm.h | 7 ++ mm/debug.c | 1 + mm/swap.c | 27 +++++- tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 75 +++++++++++++-- tools/testing/selftests/kvm/lib/kvm_util.c | 3 +- virt/kvm/Kconfig | 4 + virt/kvm/guest_memfd.c | 90 ++++++++++++++++++ virt/kvm/kvm_main.c | 9 +- 18 files changed, 326 insertions(+), 52 deletions(-) base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04