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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspam-User: X-Stat-Signature: efc1m14ztdy35sk1ykynp639yq85ssb6 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 1E7BB1A0011 X-HE-Tag: 1768398332-726185 X-HE-Meta: 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 nGW173GP 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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: [ 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 v8:=0A= - Dave: create new helpers for direct map manipulations=0A= (folio_{zap,restore}_direct_map()) instead of using=0A= set_direct_map_valid_noflush() to abstract TLB flush logic=0A= - Dave: add WARN_ON_ONCE on the error when restoring direct map=0A= - John: separate patch for dropping secretmem optimisation in=0A= gup_fast_folio_allowed()=0A= - Vlastimil: add missing clearing of the flag when restoring direct map=0A= - Reorder patches to keep the kernel compilable in between=0A= =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 (1):=0A= set_memory: add folio_{zap,restore}_direct_map helpers=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 | 22 ++++---=0A= arch/arm64/include/asm/kvm_host.h | 13 ++++=0A= arch/arm64/include/asm/set_memory.h | 2 +=0A= arch/arm64/mm/pageattr.c | 12 ++++=0A= arch/loongarch/include/asm/set_memory.h | 2 +=0A= arch/loongarch/mm/pageattr.c | 16 +++++=0A= arch/riscv/include/asm/set_memory.h | 2 +=0A= arch/riscv/mm/pageattr.c | 16 +++++=0A= arch/s390/include/asm/set_memory.h | 2 +=0A= arch/s390/mm/pageattr.c | 18 ++++++=0A= arch/x86/include/asm/kvm_host.h | 9 +++=0A= arch/x86/include/asm/set_memory.h | 2 +=0A= arch/x86/mm/pat/set_memory.c | 20 +++++++=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 | 10 ++++=0A= include/uapi/linux/kvm.h | 1 +=0A= lib/buildid.c | 4 +-=0A= mm/gup.c | 19 ++----=0A= mm/mlock.c | 2 +-=0A= mm/secretmem.c | 8 +--=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 | 58 ++++++++++++++++--=0A= 34 files changed, 406 insertions(+), 101 deletions(-)=0A= =0A= =0A= base-commit: 0499add8efd72456514c6218c062911ccc922a99=0A= -- =0A= 2.50.1=0A= =0A=