From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 45E4C8633F for ; Tue, 29 Jul 2025 22:55:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753829731; cv=none; b=LrtXHUHXL0n86lkoiLsnLHpzFtL9Xz3pjesmmLBKmi3UmluOVEZ8yb+8C7t24GPqTqDyDNiiae8/8CdjVjsNbPDQ8l/B+/k/FGnTpWPrv8nVyeR8GRI9AG4fV3jFssOHpFyM4FW8T+3bZ5PT7D4lRCgWOiibew5qKE0ynVssKgE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753829731; c=relaxed/simple; bh=E9x9+cPa6JkPTywd8ZwfDBIN3aB6QEip1AAaCabMxfo=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=YC1TxczKjBwG5lPCHAlqZDhrrryvLkS4YqFuUQL6b4nBJsZiSRMQuKe9J5+Ldsi4W1alAtBeE7iRRo2Ni5SpMJX/vuDE3hVKIl2mScsKuVghbSa7jSYOtscK2TFUCSqZdijTCRM4aKm8rJj9RRI1xjh6V490dgi/dQW5HgUc90Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=d6StkXtk; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="d6StkXtk" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-b31df10dfadso4285086a12.0 for ; Tue, 29 Jul 2025 15:55:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1753829729; x=1754434529; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=1xJQZhw5yV62Y2vPCQPybVQ771QZon9BJ9XOycOZeU8=; b=d6StkXtkbpE15+dSR5uZdz1zeUqcN2nXXJummer3hx+XumDwB/I9Mx5DuueybLpJkC TuRiYwd+IQCEc94B1wtXhe1K03rQQ2CdBHc45YBZHydil1us138p/ftbQV/yDdqqLyCh obbrkyAVmqBO45uQbfcxXJrEypcJzPp3yvkmbImlU6TjJiRUy4AtvGnAsPDXO9sgbyCu 8Dr6N8kuo/eYFs2EYAUUL3DsmJEhrp/tR3tQTeKv5BHETF1XOkRvlGtiwDRlbIINi3jX BJs/cIkxXWAfrGGQOMsRvwPulF4kNNA/5F2k9/vaZlSxS2bbsa2aoI7/bsc/g9eonjAC HjuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753829729; x=1754434529; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=1xJQZhw5yV62Y2vPCQPybVQ771QZon9BJ9XOycOZeU8=; b=tWhOmkAlOZLJta/JUU8Ap3deqkpUHeL+0tEKTbVOkhZLRfW5JvZC0gvRqJFCYzLiM+ 94QuIU6WtE7fRVbT3hSwdUu2He5MrqfiFDDgyNoPfeGeLCZKpSPqIZZi8+uzoeZP1/Ik RJpV/QHEkPVAfot0sbpAblQKy4z2QuI6ewXn8rvs+yOJlH89I28pK9nTIQXs2k91PlzQ Z8yGNauP2zAc6pJuGEpcl9k531XbUPSwkhOMKmCzla/PZ9c3e3w6mDWvKxg6NXa8sT3g TNybs41YVLHrFr+XSyKBVvl4IuSKdPT6XXi1RQ3swSuoljJ3r+Qy9dyq8LxJgCdYHYJc NjVg== X-Gm-Message-State: AOJu0YxtEFsEDxHxlahZ/8K396jVtg3rGC1tAGXOxgfO28K0qjGRrxr6 yjQn4E6kMBbmcyrhngBO1dd2RDZd8zvI+Gg/wWDuxr5d8ANdTAKn4p/FIcKeZmJ0CXAWX+TaH1P ++RYipA== X-Google-Smtp-Source: AGHT+IGaxcWmFDKGwZrWj7pqH7ospcLQPlncerJUmyl/cLjhK8EfQXRjnzM85IkOCzxza2AGNlEEwnrrJ2U= X-Received: from pfbmb27.prod.google.com ([2002:a05:6a00:761b:b0:746:18ec:d11a]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:8c9:b0:747:accb:773c with SMTP id d2e1a72fcca58-76ab2f4beabmr1613976b3a.13.1753829729537; Tue, 29 Jul 2025 15:55:29 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 29 Jul 2025 15:54:31 -0700 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.50.1.552.g942d659e1b-goog Message-ID: <20250729225455.670324-1-seanjc@google.com> Subject: [PATCH v17 00/24] KVM: Enable mmap() for guest_memfd From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Ira Weiny , Gavin Shan , Shivank Garg , Vlastimil Babka , Xiaoyao Li , David Hildenbrand , Fuad Tabba , Ackerley Tng , Tao Chan , James Houghton Content-Type: text/plain; charset="UTF-8" Paolo, The arm64 patches have been Reviewed-by Marc, and AFAICT the x86 side of things is a go. Barring a screwup on my end, this just needs your approval. Assuming everything looks good, it'd be helpful to get this into kvm/next shortly after rc1. The x86 Kconfig changes in particular create semantic conflicts with in-flight series. Add support for host userspace mapping of guest_memfd-backed memory for VM types that do NOT use support KVM_MEMORY_ATTRIBUTE_PRIVATE (which isn't precisely the same thing as CoCo VMs, since x86's SEV-MEM and SEV-ES have no way to detect private vs. shared). mmap() support paves the way for several evolving KVM use cases: * Allows VMMs like Firecracker to run guests entirely backed by guest_memfd [1]. This provides a unified memory management model for both confidential and non-confidential guests, simplifying VMM design. * Enhanced Security via direct map removal: When combined with Patrick's series for direct map removal [2], this provides additional hardening against Spectre-like transient execution attacks by eliminating the need for host kernel direct maps of guest memory. * Lays the groundwork for *restricted* mmap() support for guest_memfd-backed memory on CoCo platforms [3] that permit in-place sharing of guest memory with the host. Based on kvm/queue. [1] https://github.com/firecracker-microvm/firecracker/tree/feature/secret-hiding [2] https://lore.kernel.org/all/20250221160728.1584559-1-roypat@amazon.co.uk [3] https://lore.kernel.org/all/20250328153133.3504118-1-tabba@google.com v17: - Collect reviews. [Xiaoyao, David H.] - Write a better changelog for the CONFIG_KVM_GENERIC_PRIVATE_MEM => CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE rename. [Xiaoyao] - Correctly gmem_max_mapping_level()'s '0' return in the right patch. [Xiaoyao] - Replace call to kvm_gmem_get_pfn() with a WARN_ONCE() in the hugepage recovery path. [Ackerley] - Add back "KVM: x86/mmu: Handle guest page faults for guest_memfd with shared memory". [Ackerley] - Rework the selftest flags testcase to query MMAP support for a given VM type instead of hardcoding expectations in the test. [Sean] - Add a testcase to verify KVM can map guest_memfd memory into the guest even if the userspace address in the memslot isn't (properly) mmap'd. [Sean] v16: - https://lore.kernel.org/all/20250723104714.1674617-1-tabba@google.com - Rework and simplify Kconfig selection and dependencies. - Always enable guest_memfd for KVM x86 (64-bit) and arm64, which simplifies the enablement checks. - Based on kvm-x86/next: commit 33f843444e28 ("Merge branch 'vmx'"). v15: - https://lore.kernel.org/all/20250717162731.446579-1-tabba@google.com - Removed KVM_SW_PROTECTED_VM dependency on KVM_GENERIC_GMEM_POPULATE - Fixed some commit messages v14: - https://lore.kernel.org/all/20250715093350.2584932-1-tabba@google.com - Fixed handling of guest faults in case of invalidation in arm64 - Handle VNCR_EL2-triggered faults backed by guest_memfd (arm64 nested virt) - Applied suggestions from latest feedback - Rebase on Linux 6.16-rc6 Ackerley Tng (2): KVM: x86/mmu: Rename .private_max_mapping_level() to .gmem_max_mapping_level() KVM: x86/mmu: Handle guest page faults for guest_memfd with shared memory Fuad Tabba (15): KVM: Rename CONFIG_KVM_PRIVATE_MEM to CONFIG_KVM_GUEST_MEMFD KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE KVM: Rename kvm_slot_can_be_private() to kvm_slot_has_gmem() KVM: Fix comments that refer to slots_lock KVM: Fix comment that refers to kvm uapi header path KVM: x86: Enable KVM_GUEST_MEMFD for all 64-bit builds KVM: guest_memfd: Add plumbing to host to map guest_memfd pages KVM: guest_memfd: Track guest_memfd mmap support in memslot KVM: arm64: Refactor user_mem_abort() KVM: arm64: Handle guest_memfd-backed guest page faults KVM: arm64: nv: Handle VNCR_EL2-triggered faults backed by guest_memfd KVM: arm64: Enable support for guest_memfd backed memory KVM: Allow and advertise support for host mmap() on guest_memfd files KVM: selftests: Do not use hardcoded page sizes in guest_memfd test KVM: selftests: guest_memfd mmap() test when mmap is supported Sean Christopherson (7): KVM: x86: Have all vendor neutral sub-configs depend on KVM_X86, not just KVM KVM: x86: Select KVM_GENERIC_PRIVATE_MEM directly from KVM_SW_PROTECTED_VM KVM: x86: Select TDX's KVM_GENERIC_xxx dependencies iff CONFIG_KVM_INTEL_TDX=y KVM: x86/mmu: Hoist guest_memfd max level/order helpers "up" in mmu.c KVM: x86/mmu: Enforce guest_memfd's max order when recovering hugepages KVM: x86/mmu: Extend guest_memfd's max mapping level to shared mappings KVM: selftests: Add guest_memfd testcase to fault-in on !mmap()'d memory Documentation/virt/kvm/api.rst | 9 + arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/mmu.c | 203 +++++++++++---- arch/arm64/kvm/nested.c | 41 ++- arch/x86/include/asm/kvm-x86-ops.h | 2 +- arch/x86/include/asm/kvm_host.h | 6 +- arch/x86/kvm/Kconfig | 26 +- arch/x86/kvm/mmu/mmu.c | 142 ++++++----- arch/x86/kvm/mmu/mmu_internal.h | 2 +- arch/x86/kvm/mmu/tdp_mmu.c | 2 +- arch/x86/kvm/svm/sev.c | 6 +- arch/x86/kvm/svm/svm.c | 2 +- arch/x86/kvm/svm/svm.h | 4 +- arch/x86/kvm/vmx/main.c | 7 +- arch/x86/kvm/vmx/tdx.c | 5 +- arch/x86/kvm/vmx/x86_ops.h | 2 +- arch/x86/kvm/x86.c | 11 + include/linux/kvm_host.h | 38 +-- include/uapi/linux/kvm.h | 2 + tools/testing/selftests/kvm/Makefile.kvm | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 236 ++++++++++++++++-- virt/kvm/Kconfig | 15 +- virt/kvm/Makefile.kvm | 2 +- virt/kvm/guest_memfd.c | 81 +++++- virt/kvm/kvm_main.c | 12 +- virt/kvm/kvm_mm.h | 4 +- 26 files changed, 648 insertions(+), 214 deletions(-) base-commit: beafd7ecf2255e8b62a42dc04f54843033db3d24 -- 2.50.1.552.g942d659e1b-goog