From patchwork Thu Sep 14 01:55:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13383979 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2A88EE021C for ; Thu, 14 Sep 2023 01:57:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234382AbjINB5G (ORCPT ); Wed, 13 Sep 2023 21:57:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233804AbjINB4F (ORCPT ); Wed, 13 Sep 2023 21:56:05 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E7E4212E for ; Wed, 13 Sep 2023 18:55:49 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-59b56dab74bso6570397b3.2 for ; Wed, 13 Sep 2023 18:55:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1694656548; x=1695261348; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=BhxGep0GRUEwAUAzFvnYRN6yWfiwAK/IRlQcI8pBhpQ=; b=e7/6zTFxm8G6xsrAvZUmuDMpnu0BLzpds/1OX8d4vOfYN1DtxBqxwcLOZgHTRIQ/5X 90pY50iRRJMPwt6alQ5c9vbGFWvGEs4UstLm/cnngn3dD/2KkPueVpTksfVdhYyZhVez rDns+Y18pY5OeaYFp0OOk8gPpHOSWm0uElTUebYOKIfBOO+1VilLrSTtn5MGxGBQ+Xne gpnqCnn2qCV5Tbl84pluofhKAOLLQGhrI12t8rk3OukGL+dOs2DCj3VxBJhKn142tEUC CjTDvqTqQusNrnCMWrRrOGXke/MJ8rN1Bi/ukZCelJvnjzCZV8PrJboUUmOB6cEVmFSC hdFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694656548; x=1695261348; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=BhxGep0GRUEwAUAzFvnYRN6yWfiwAK/IRlQcI8pBhpQ=; b=HaHCBqa3ZPd2dIfWh7Zt1L4sbtPLPNz4myHb0uCRbi2/sHhwa/J8Bx6DQ6ZercETMI o+OS3VUDPV/DbP75QOh8CHKg3f+kzgUMqBGIQKDwtgki6IZA1+lnCSo33TMfbqk3NlIa OCm6hdosvVBA9Bz6RCrslgKuwxUd0nauFF7GpHiCN2NIR6LerZFWnGY46iSP0lFHRM7p 4BIb+8XPG16/ctkqjmBtGzum76gjM29/C239csTgJzUApY4+x+ba118n+cZIx+Ybuh5G 6OIcwv9LEMT36yBBCncywYf22+BruQ7sh/Bylp3S79wevok7n8ERE4ad7NdCa+skeh5Y 8Krw== X-Gm-Message-State: AOJu0YzzAQOTTJx3WuGJ1eJPIy0Hda6Bpj/vGEtShspTJFgSvw8q30j8 m68sOaHc5Ri2rqUDh5DtVJRX0HkAznQ= X-Google-Smtp-Source: AGHT+IFIu1rjOq9FW+JbDj5fY4BKSa/epsGGWccSSMIHRlmCarPy2ezJLxiJZod49VfvzwgQV9RD5huQPI8= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:4207:0:b0:d81:536d:2978 with SMTP id p7-20020a254207000000b00d81536d2978mr74175yba.2.1694656548405; Wed, 13 Sep 2023 18:55:48 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 13 Sep 2023 18:55:04 -0700 In-Reply-To: <20230914015531.1419405-1-seanjc@google.com> Mime-Version: 1.0 References: <20230914015531.1419405-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.283.g2d96d420d3-goog Message-ID: <20230914015531.1419405-7-seanjc@google.com> Subject: [RFC PATCH v12 06/33] KVM: Introduce KVM_SET_USER_MEMORY_REGION2 From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Anish Moorthy , Yu Zhang , Isaku Yamahata , Xu Yilun , Vlastimil Babka , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Introduce a "version 2" of KVM_SET_USER_MEMORY_REGION so that additional information can be supplied without setting userspace up to fail. The padding in the new kvm_userspace_memory_region2 structure will be used to pass a file descriptor in addition to the userspace_addr, i.e. allow userspace to point at a file descriptor and map memory into a guest that is NOT mapped into host userspace. Alternatively, KVM could simply add "struct kvm_userspace_memory_region2" without a new ioctl(), but as Paolo pointed out, adding a new ioctl() makes detection of bad flags a bit more robust, e.g. if the new fd field is guarded only by a flag and not a new ioctl(), then a userspace bug (setting a "bad" flag) would generate out-of-bounds access instead of an -EINVAL error. Cc: Jarkko Sakkinen Reviewed-by: Paolo Bonzini Signed-off-by: Sean Christopherson Reviewed-by: Xiaoyao Li --- arch/x86/kvm/x86.c | 2 +- include/linux/kvm_host.h | 4 ++-- include/uapi/linux/kvm.h | 13 +++++++++++++ virt/kvm/kvm_main.c | 38 ++++++++++++++++++++++++++++++-------- 4 files changed, 46 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6c9c81e82e65..8356907079e1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12447,7 +12447,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, } for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { - struct kvm_userspace_memory_region m; + struct kvm_userspace_memory_region2 m; m.slot = id | (i << 16); m.flags = 0; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5faba69403ac..4e741ff27af3 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1146,9 +1146,9 @@ enum kvm_mr_change { }; int kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem); + const struct kvm_userspace_memory_region2 *mem); int __kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem); + const struct kvm_userspace_memory_region2 *mem); void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot); void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen); int kvm_arch_prepare_memory_region(struct kvm *kvm, diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 13065dd96132..bd1abe067f28 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -95,6 +95,16 @@ struct kvm_userspace_memory_region { __u64 userspace_addr; /* start of the userspace allocated memory */ }; +/* for KVM_SET_USER_MEMORY_REGION2 */ +struct kvm_userspace_memory_region2 { + __u32 slot; + __u32 flags; + __u64 guest_phys_addr; + __u64 memory_size; + __u64 userspace_addr; + __u64 pad[16]; +}; + /* * The bit 0 ~ bit 15 of kvm_userspace_memory_region::flags are visible for * userspace, other bits are reserved for kvm internal use which are defined @@ -1192,6 +1202,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_COUNTER_OFFSET 227 #define KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 228 #define KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES 229 +#define KVM_CAP_USER_MEMORY2 230 #ifdef KVM_CAP_IRQ_ROUTING @@ -1473,6 +1484,8 @@ struct kvm_vfio_spapr_tce { struct kvm_userspace_memory_region) #define KVM_SET_TSS_ADDR _IO(KVMIO, 0x47) #define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO, 0x48, __u64) +#define KVM_SET_USER_MEMORY_REGION2 _IOW(KVMIO, 0x49, \ + struct kvm_userspace_memory_region2) /* enable ucontrol for s390 */ struct kvm_s390_ucas_mapping { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8d21757cd5e9..7c0e38752526 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1571,7 +1571,7 @@ static void kvm_replace_memslot(struct kvm *kvm, } } -static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem) +static int check_memory_region_flags(const struct kvm_userspace_memory_region2 *mem) { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; @@ -1973,7 +1973,7 @@ static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id, * Must be called holding kvm->slots_lock for write. */ int __kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem) + const struct kvm_userspace_memory_region2 *mem) { struct kvm_memory_slot *old, *new; struct kvm_memslots *slots; @@ -2077,7 +2077,7 @@ int __kvm_set_memory_region(struct kvm *kvm, EXPORT_SYMBOL_GPL(__kvm_set_memory_region); int kvm_set_memory_region(struct kvm *kvm, - const struct kvm_userspace_memory_region *mem) + const struct kvm_userspace_memory_region2 *mem) { int r; @@ -2089,7 +2089,7 @@ int kvm_set_memory_region(struct kvm *kvm, EXPORT_SYMBOL_GPL(kvm_set_memory_region); static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm, - struct kvm_userspace_memory_region *mem) + struct kvm_userspace_memory_region2 *mem) { if ((u16)mem->slot >= KVM_USER_MEM_SLOTS) return -EINVAL; @@ -4559,6 +4559,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) { switch (arg) { case KVM_CAP_USER_MEMORY: + case KVM_CAP_USER_MEMORY2: case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS: case KVM_CAP_INTERNAL_ERROR_DATA: @@ -4814,6 +4815,14 @@ static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm) return fd; } +#define SANITY_CHECK_MEM_REGION_FIELD(field) \ +do { \ + BUILD_BUG_ON(offsetof(struct kvm_userspace_memory_region, field) != \ + offsetof(struct kvm_userspace_memory_region2, field)); \ + BUILD_BUG_ON(sizeof_field(struct kvm_userspace_memory_region, field) != \ + sizeof_field(struct kvm_userspace_memory_region2, field)); \ +} while (0) + static long kvm_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -4836,15 +4845,28 @@ static long kvm_vm_ioctl(struct file *filp, r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap); break; } + case KVM_SET_USER_MEMORY_REGION2: case KVM_SET_USER_MEMORY_REGION: { - struct kvm_userspace_memory_region kvm_userspace_mem; + struct kvm_userspace_memory_region2 mem; + unsigned long size; + + if (ioctl == KVM_SET_USER_MEMORY_REGION) + size = sizeof(struct kvm_userspace_memory_region); + else + size = sizeof(struct kvm_userspace_memory_region2); + + /* Ensure the common parts of the two structs are identical. */ + SANITY_CHECK_MEM_REGION_FIELD(slot); + SANITY_CHECK_MEM_REGION_FIELD(flags); + SANITY_CHECK_MEM_REGION_FIELD(guest_phys_addr); + SANITY_CHECK_MEM_REGION_FIELD(memory_size); + SANITY_CHECK_MEM_REGION_FIELD(userspace_addr); r = -EFAULT; - if (copy_from_user(&kvm_userspace_mem, argp, - sizeof(kvm_userspace_mem))) + if (copy_from_user(&mem, argp, size)) goto out; - r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem); + r = kvm_vm_ioctl_set_memory_region(kvm, &mem); break; } case KVM_GET_DIRTY_LOG: {