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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspamd-Queue-Id: 1889240017 X-Stat-Signature: j7cuseo88qzd7wfnpyx7psuzg5iyy34p X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1773756645-116686 X-HE-Meta: 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 lZByOAO3 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: [ based on kvm/next ]=0A= =0A= Unmapping virtual machine guest memory from the host kernel's direct map=0A= is a successful mitigation against Spectre-style transient execution=0A= issues: if the kernel page tables do not contain entries pointing to=0A= guest memory, then any attempted speculative read through the direct map=0A= will necessarily be blocked by the MMU before any observable=0A= microarchitectural side-effects happen. This means that Spectre-gadgets=0A= and similar cannot be used to target virtual machine memory. Roughly=0A= 60% of speculative execution issues fall into this category [1, Table=0A= 1].=0A= =0A= This patch series extends guest_memfd with the ability to remove its=0A= memory from the host kernel's direct map, to be able to attain the above=0A= protection for KVM guests running inside guest_memfd.=0A= =0A= Additionally, a Firecracker branch with support for these VMs can be=0A= found on GitHub [2].=0A= =0A= For more details, please refer to the v5 cover letter. No substantial=0A= changes in design have taken place since.=0A= =0A= See also related write() syscall support in guest_memfd [3] where=0A= the interoperation between the two features is described.=0A= =0A= Changes since v10:=0A= - David: use a generic implementation for=0A= folio_{zap,restore}_direct_map instead of per-arch and return void=0A= from folio_restore_direct_map instead of int. Ackerley, I dropped your= =0A= "Reviewed-by:" as the patch 02/16 has changed significantly. Could you= =0A= have another look when you have time?=0A= - David: fix: kvm_gmem_folio_zap_direct_map: do not set=0A= KVM_GMEM_FOLIO_NO_DIRECT_MAP on failure=0A= - David: minor readability fixes=0A= =0A= v10: https://lore.kernel.org/kvm/20260126164445.11867-1-kalyazin@amazon.com= =0A= v9: https://lore.kernel.org/kvm/20260114134510.1835-1-kalyazin@amazon.com= =0A= v8: https://lore.kernel.org/kvm/20251205165743.9341-1-kalyazin@amazon.com= =0A= v7: https://lore.kernel.org/kvm/20250924151101.2225820-1-patrick.roy@campus= .lmu.de=0A= v6: https://lore.kernel.org/kvm/20250912091708.17502-1-roypat@amazon.co.uk= =0A= v5: https://lore.kernel.org/kvm/20250828093902.2719-1-roypat@amazon.co.uk= =0A= v4: https://lore.kernel.org/kvm/20250221160728.1584559-1-roypat@amazon.co.u= k=0A= RFCv3: https://lore.kernel.org/kvm/20241030134912.515725-1-roypat@amazon.co= .uk=0A= RFCv2: https://lore.kernel.org/kvm/20240910163038.1298452-1-roypat@amazon.c= o.uk=0A= RFCv1: https://lore.kernel.org/kvm/20240709132041.3625501-1-roypat@amazon.c= o.uk=0A= =0A= [1] https://download.vusec.net/papers/quarantine_raid23.pdf=0A= [2] https://github.com/firecracker-microvm/firecracker/tree/feature/secret-= hiding=0A= [3] https://lore.kernel.org/kvm/20251114151828.98165-1-kalyazin@amazon.com= =0A= =0A= Nikita Kalyazin (4):=0A= set_memory: set_direct_map_* to take address=0A= set_memory: add folio_{zap,restore}_direct_map helpers=0A= mm/secretmem: make use of folio_{zap,restore}_direct_map=0A= mm/gup: drop local variable in gup_fast_folio_allowed=0A= =0A= Patrick Roy (12):=0A= mm/gup: drop secretmem optimization from gup_fast_folio_allowed=0A= mm: introduce AS_NO_DIRECT_MAP=0A= KVM: guest_memfd: Add stub for kvm_arch_gmem_invalidate=0A= KVM: x86: define kvm_arch_gmem_supports_no_direct_map()=0A= KVM: arm64: define kvm_arch_gmem_supports_no_direct_map()=0A= KVM: guest_memfd: Add flag to remove from direct map=0A= KVM: selftests: load elf via bounce buffer=0A= KVM: selftests: set KVM_MEM_GUEST_MEMFD in vm_mem_add() if guest_memfd=0A= !=3D -1=0A= KVM: selftests: Add guest_memfd based vm_mem_backing_src_types=0A= KVM: selftests: cover GUEST_MEMFD_FLAG_NO_DIRECT_MAP in existing=0A= selftests=0A= KVM: selftests: stuff vm_mem_backing_src_type into vm_shape=0A= KVM: selftests: Test guest execution from direct map removed gmem=0A= =0A= Documentation/virt/kvm/api.rst | 21 +++---=0A= arch/arm64/include/asm/kvm_host.h | 13 ++++=0A= arch/arm64/include/asm/set_memory.h | 7 +-=0A= arch/arm64/mm/pageattr.c | 19 +++--=0A= arch/loongarch/include/asm/set_memory.h | 8 ++-=0A= arch/loongarch/mm/pageattr.c | 25 +++----=0A= arch/riscv/include/asm/set_memory.h | 7 +-=0A= arch/riscv/mm/pageattr.c | 17 ++---=0A= arch/s390/include/asm/set_memory.h | 7 +-=0A= arch/s390/mm/pageattr.c | 13 ++--=0A= arch/x86/include/asm/kvm_host.h | 6 ++=0A= arch/x86/include/asm/set_memory.h | 7 +-=0A= arch/x86/kvm/x86.c | 5 ++=0A= arch/x86/mm/pat/set_memory.c | 23 +++---=0A= include/linux/kvm_host.h | 14 ++++=0A= include/linux/pagemap.h | 16 +++++=0A= include/linux/secretmem.h | 18 -----=0A= include/linux/set_memory.h | 22 ++++--=0A= include/uapi/linux/kvm.h | 1 +=0A= kernel/power/snapshot.c | 4 +-=0A= lib/buildid.c | 8 ++-=0A= mm/execmem.c | 6 +-=0A= mm/gup.c | 41 +++++------=0A= mm/memory.c | 42 +++++++++++=0A= mm/mlock.c | 2 +-=0A= mm/secretmem.c | 18 ++---=0A= mm/vmalloc.c | 11 +--=0A= .../testing/selftests/kvm/guest_memfd_test.c | 17 ++++-=0A= .../testing/selftests/kvm/include/kvm_util.h | 37 +++++++---=0A= .../testing/selftests/kvm/include/test_util.h | 8 +++=0A= tools/testing/selftests/kvm/lib/elf.c | 8 +--=0A= tools/testing/selftests/kvm/lib/io.c | 23 ++++++=0A= tools/testing/selftests/kvm/lib/kvm_util.c | 59 ++++++++-------=0A= tools/testing/selftests/kvm/lib/test_util.c | 8 +++=0A= tools/testing/selftests/kvm/lib/x86/sev.c | 1 +=0A= .../selftests/kvm/pre_fault_memory_test.c | 1 +=0A= .../selftests/kvm/set_memory_region_test.c | 52 ++++++++++++--=0A= .../kvm/x86/private_mem_conversions_test.c | 7 +-=0A= virt/kvm/guest_memfd.c | 71 ++++++++++++++++---=0A= 39 files changed, 474 insertions(+), 199 deletions(-)=0A= =0A= =0A= base-commit: d2ea4ff1ce50787a98a3900b3fb1636f3620b7cf=0A= -- =0A= 2.50.1=0A= =0A=