From nobody Sun Feb 8 23:24:44 2026 Received: from mail-vk1-f201.google.com (mail-vk1-f201.google.com [209.85.221.201]) (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 0FB1F1C3C10 for ; Wed, 4 Dec 2024 19:14:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733339661; cv=none; b=Q/It8qj65KvGFzriiawFVX32DxdElxwGkBFsOix6qd6En2LHnB68q2VaxDJgyiKy2eb2aO7BFcEJ1BWT0XI8f/V4YCZlNV2iuoIgsudlnShBFBp3XpWpTLFgvXiF7oq12Xno8I/+HWgtW3S0TExM2QQmD2bHBGvpITQYqYNPqGg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733339661; c=relaxed/simple; bh=gwG4wHoxIC9ohviESrC4i1SBquoILkHgmJR3YvyQL40=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=XNiq4X3NRB8Vh759dM2dmC/v8WoBYHNW7G9yrHMzd9g9QLh7q1aF1/Ki4B/bJJKND+CvK7ShG2bBnC8bQjx0FpwU7QgrR4al6KKrgi75bxCQNBadFUeDz8vEIcKdNCXZyx4K81jQSmCIB32oVSXqf4pOAOWTZ5Ii83PUnf9xsdA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jthoughton.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=HynfjS9g; arc=none smtp.client-ip=209.85.221.201 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--jthoughton.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="HynfjS9g" Received: by mail-vk1-f201.google.com with SMTP id 71dfb90a1353d-515cf20f2c7so13017e0c.0 for ; Wed, 04 Dec 2024 11:14:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733339658; x=1733944458; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=rnZJyT6N3r8vTjoa4UcLa/XGdQ+PqihxUkrotorxiRo=; b=HynfjS9gexIPiXe0xn8pvL/i2eC2Ggh91wY+OOggUnrAwLxAjOIBijfWJSvdnLKJOA IDIQ0UpU4YJKosuerBA3hZPGSkUY5DOfLZTe2xv9Oma6DL0ILGK14eogVDe1tH3R4aHu WDaB3GyTR/CkclNtL/FiD1aMx7xwLuW5CoixkQWJxTbzFnoN6bD7bo6atK6prLlAIy+d eFA8kbCN1gEQPGR7ICo/vdLJu5zic2VZrqAV6SAZds5uEkZeHz3z2tWVEiFIw42C+uYf sUP+a1/E0aH/MMPZYF78OdT5A65OzEfKhfDNGfcuCFyjQhjpidTPdTds+toCaSmVnS+l z0Jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733339658; x=1733944458; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=rnZJyT6N3r8vTjoa4UcLa/XGdQ+PqihxUkrotorxiRo=; b=AUHnxZHoJ+iCEX+a71rC8ULXLc+99RBsJTiTQQtqDbom4qjnmi/UKS5ing7atTuFk1 ZI3EgVK871mp/puyKqyftIuCpfrSg4Eri9ySF/REUw2+BRfdez8WFmKUbGvA/8cqAcvl YLOPhULEa8rZ7y88txWloSkw9AO/0HOq+PJd4TNpq12ovHx972iS3TiFF48mKf09NXEt +Ec+atOvyGUcpF+mutiTeDNl7sHKxLNM44stIbd0qKKb7LKKsNHoiMDepKp0h9xsCG98 7m72fR12uRQq1coDP+zOR0vLpkiAFyoXxLTvbh3L4IZkEKu54m+EJtCfTSSlCgNDSjyp mMvA== X-Forwarded-Encrypted: i=1; AJvYcCV4TjRQmdFbOsOrvcHsnFZaId892JLLVjiNkdbORa8xqCLma0945TUbidezFf+QO3/ZXiq4khmQYeqpdYo=@vger.kernel.org X-Gm-Message-State: AOJu0YxLmipI7JNJRwnfq4CqjmarQoJi8XAwDOQmM8I01xDOknKcF3tt lwaA+oE2KautnNCyEinJ0PlQPYV04zsuyWXSDhVkczIxirX4OxaiVwAO8oduSHbU/VKbLlRXtUu TVMHKxS93Krycg+awVQ== X-Google-Smtp-Source: AGHT+IHeflh53wCdtG/eOTj3NVvzDZ1TR16bpwDBvuZyMyTF5KFF0ZrmPFZ5n9dphqqxj6PK08wZjYTOW77Q8bPv X-Received: from vkbfc18.prod.google.com ([2002:a05:6122:4b12:b0:50d:6d20:c212]) (user=jthoughton job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6122:8d0:b0:50d:4cb8:5aef with SMTP id 71dfb90a1353d-515bf2ff82amr10640137e0c.6.1733339657905; Wed, 04 Dec 2024 11:14:17 -0800 (PST) Date: Wed, 4 Dec 2024 19:13:38 +0000 In-Reply-To: <20241204191349.1730936-1-jthoughton@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241204191349.1730936-1-jthoughton@google.com> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog Message-ID: <20241204191349.1730936-4-jthoughton@google.com> Subject: [PATCH v1 03/13] KVM: Allow late setting of KVM_MEM_USERFAULT on guest_memfd memslot From: James Houghton To: Paolo Bonzini , Sean Christopherson Cc: Jonathan Corbet , Marc Zyngier , Oliver Upton , Yan Zhao , James Houghton , Nikita Kalyazin , Anish Moorthy , Peter Gonda , Peter Xu , David Matlack , Wang@google.com, Wei W , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently guest_memfd memslots can only be deleted. Slightly change the logic to allow KVM_MR_FLAGS_ONLY changes when the only flag being changed is KVM_MEM_USERFAULT. Signed-off-by: James Houghton --- virt/kvm/kvm_main.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 23fa3e911c4e..fa851704db94 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2009,9 +2009,6 @@ int __kvm_set_memory_region(struct kvm *kvm, if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages) return -EINVAL; } else { /* Modify an existing slot. */ - /* Private memslots are immutable, they can only be deleted. */ - if (mem->flags & KVM_MEM_GUEST_MEMFD) - return -EINVAL; if ((mem->userspace_addr !=3D old->userspace_addr) || (npages !=3D old->npages) || ((mem->flags ^ old->flags) & KVM_MEM_READONLY)) @@ -2025,6 +2022,16 @@ int __kvm_set_memory_region(struct kvm *kvm, return 0; } =20 + /* + * Except for being able to set KVM_MEM_USERFAULT, private memslots are + * immutable, they can only be deleted. + */ + if (mem->flags & KVM_MEM_GUEST_MEMFD && + !(change =3D=3D KVM_MR_CREATE || + (change =3D=3D KVM_MR_FLAGS_ONLY && + (mem->flags ^ old->flags) =3D=3D KVM_MEM_USERFAULT))) + return -EINVAL; + if ((change =3D=3D KVM_MR_CREATE || change =3D=3D KVM_MR_MOVE) && kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages)) return -EEXIST; @@ -2040,7 +2047,7 @@ int __kvm_set_memory_region(struct kvm *kvm, new->npages =3D npages; new->flags =3D mem->flags; new->userspace_addr =3D mem->userspace_addr; - if (mem->flags & KVM_MEM_GUEST_MEMFD) { + if (mem->flags & KVM_MEM_GUEST_MEMFD && change =3D=3D KVM_MR_CREATE) { r =3D kvm_gmem_bind(kvm, new, mem->guest_memfd, mem->guest_memfd_offset); if (r) goto out; --=20 2.47.0.338.g60cca15819-goog