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Fri, 5 Dec 2025 16:59:49 +0000 (UTC) X-Farcaster-Flow-ID: 34fe6e69-dd5b-4480-b95e-ddc8757a2feb Received: from EX19D005EUB002.ant.amazon.com (10.252.51.103) by EX19MTAEUB002.ant.amazon.com (10.252.51.79) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.29; Fri, 5 Dec 2025 16:59:41 +0000 Received: from EX19D005EUB003.ant.amazon.com (10.252.51.31) by EX19D005EUB002.ant.amazon.com (10.252.51.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.29; Fri, 5 Dec 2025 16:59:40 +0000 Received: from EX19D005EUB003.ant.amazon.com ([fe80::b825:becb:4b38:da0c]) by EX19D005EUB003.ant.amazon.com ([fe80::b825:becb:4b38:da0c%3]) with mapi id 15.02.2562.029; Fri, 5 Dec 2025 16:59:40 +0000 From: "Kalyazin, Nikita" To: "kvm@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "kvmarm@lists.linux.dev" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" CC: "pbonzini@redhat.com" , "corbet@lwn.net" , "maz@kernel.org" , "oupton@kernel.org" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "seanjc@google.com" , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "luto@kernel.org" , "peterz@infradead.org" , "willy@infradead.org" , "akpm@linux-foundation.org" , "david@kernel.org" , "lorenzo.stoakes@oracle.com" , "Liam.Howlett@oracle.com" , "vbabka@suse.cz" , "rppt@kernel.org" , "surenb@google.com" , "mhocko@suse.com" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "martin.lau@linux.dev" , "eddyz87@gmail.com" , "song@kernel.org" , "yonghong.song@linux.dev" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" , "sdf@fomichev.me" , "haoluo@google.com" , "jolsa@kernel.org" , "jgg@ziepe.ca" , "jhubbard@nvidia.com" , "peterx@redhat.com" , "jannh@google.com" , "pfalcato@suse.de" , "shuah@kernel.org" , "riel@surriel.com" , "baohua@kernel.org" , "ryan.roberts@arm.com" , "jgross@suse.com" , "yu-cheng.yu@intel.com" , "kas@kernel.org" , "coxu@redhat.com" , "kevin.brodsky@arm.com" , "ackerleytng@google.com" , "maobibo@loongson.cn" , "prsampat@amd.com" , "mlevitsk@redhat.com" , "isaku.yamahata@intel.com" , "jmattson@google.com" , "jthoughton@google.com" , "linux-arm-kernel@lists.infradead.org" , "vannapurve@google.com" , "jackmanb@google.com" , "aneesh.kumar@kernel.org" , "patrick.roy@linux.dev" , "Thomson, Jack" , "Itazuri, Takahiro" , "Manwaring, Derek" , "Cali, Marco" , "Kalyazin, Nikita" Subject: [PATCH v8 10/13] KVM: selftests: Add guest_memfd based vm_mem_backing_src_types Thread-Topic: [PATCH v8 10/13] KVM: selftests: Add guest_memfd based vm_mem_backing_src_types Thread-Index: AQHcZgiLyS0oCQO1nUODCs70+4I+GA== Date: Fri, 5 Dec 2025 16:59:40 +0000 Message-ID: <20251205165743.9341-11-kalyazin@amazon.com> References: <20251205165743.9341-1-kalyazin@amazon.com> In-Reply-To: <20251205165743.9341-1-kalyazin@amazon.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Patrick Roy =0A= =0A= Allow selftests to configure their memslots such that userspace_addr is=0A= set to a MAP_SHARED mapping of the guest_memfd that's associated with=0A= the memslot. This setup is the configuration for non-CoCo VMs, where all=0A= guest memory is backed by a guest_memfd whose folios are all marked=0A= shared, but KVM is still able to access guest memory to provide=0A= functionality such as MMIO emulation on x86.=0A= =0A= Add backing types for normal guest_memfd, as well as direct map removed=0A= guest_memfd.=0A= =0A= Signed-off-by: Patrick Roy =0A= Signed-off-by: Nikita Kalyazin =0A= ---=0A= .../testing/selftests/kvm/include/kvm_util.h | 18 ++++++=0A= .../testing/selftests/kvm/include/test_util.h | 7 +++=0A= tools/testing/selftests/kvm/lib/kvm_util.c | 61 ++++++++++---------=0A= tools/testing/selftests/kvm/lib/test_util.c | 8 +++=0A= 4 files changed, 65 insertions(+), 29 deletions(-)=0A= =0A= diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing= /selftests/kvm/include/kvm_util.h=0A= index 81f4355ff28a..6689b43810c1 100644=0A= --- a/tools/testing/selftests/kvm/include/kvm_util.h=0A= +++ b/tools/testing/selftests/kvm/include/kvm_util.h=0A= @@ -641,6 +641,24 @@ static inline bool is_smt_on(void)=0A= =0A= void vm_create_irqchip(struct kvm_vm *vm);=0A= =0A= +static inline uint32_t backing_src_guest_memfd_flags(enum vm_mem_backing_s= rc_type t)=0A= +{=0A= + uint32_t flags =3D 0;=0A= +=0A= + switch (t) {=0A= + case VM_MEM_SRC_GUEST_MEMFD_NO_DIRECT_MAP:=0A= + flags |=3D GUEST_MEMFD_FLAG_NO_DIRECT_MAP;=0A= + fallthrough;=0A= + case VM_MEM_SRC_GUEST_MEMFD:=0A= + flags |=3D GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_INIT_SHARED;=0A= + break;=0A= + default:=0A= + break;=0A= + }=0A= +=0A= + return flags;=0A= +}=0A= +=0A= static inline int __vm_create_guest_memfd(struct kvm_vm *vm, uint64_t size= ,=0A= uint64_t flags)=0A= {=0A= diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testin= g/selftests/kvm/include/test_util.h=0A= index 8140e59b59e5..ea6de20ce8ef 100644=0A= --- a/tools/testing/selftests/kvm/include/test_util.h=0A= +++ b/tools/testing/selftests/kvm/include/test_util.h=0A= @@ -152,6 +152,8 @@ enum vm_mem_backing_src_type {=0A= VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB,=0A= VM_MEM_SRC_SHMEM,=0A= VM_MEM_SRC_SHARED_HUGETLB,=0A= + VM_MEM_SRC_GUEST_MEMFD,=0A= + VM_MEM_SRC_GUEST_MEMFD_NO_DIRECT_MAP,=0A= NUM_SRC_TYPES,=0A= };=0A= =0A= @@ -184,6 +186,11 @@ static inline bool backing_src_is_shared(enum vm_mem_b= acking_src_type t)=0A= return vm_mem_backing_src_alias(t)->flag & MAP_SHARED;=0A= }=0A= =0A= +static inline bool backing_src_is_guest_memfd(enum vm_mem_backing_src_type= t)=0A= +{=0A= + return t =3D=3D VM_MEM_SRC_GUEST_MEMFD || t =3D=3D VM_MEM_SRC_GUEST_MEMFD= _NO_DIRECT_MAP;=0A= +}=0A= +=0A= static inline bool backing_src_can_be_huge(enum vm_mem_backing_src_type t)= =0A= {=0A= return t !=3D VM_MEM_SRC_ANONYMOUS && t !=3D VM_MEM_SRC_SHMEM;=0A= diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/sel= ftests/kvm/lib/kvm_util.c=0A= index 56ddbca91850..28ee51253909 100644=0A= --- a/tools/testing/selftests/kvm/lib/kvm_util.c=0A= +++ b/tools/testing/selftests/kvm/lib/kvm_util.c=0A= @@ -1013,6 +1013,33 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backi= ng_src_type src_type,=0A= alignment =3D 1;=0A= #endif=0A= =0A= + if (guest_memfd < 0) {=0A= + if ((flags & KVM_MEM_GUEST_MEMFD) || backing_src_is_guest_memfd(src_type= )) {=0A= + uint32_t guest_memfd_flags =3D backing_src_guest_memfd_flags(src_type);= =0A= +=0A= + TEST_ASSERT(!guest_memfd_offset,=0A= + "Offset must be zero when creating new guest_memfd");=0A= + guest_memfd =3D vm_create_guest_memfd(vm, mem_size, guest_memfd_flags);= =0A= + }=0A= + } else {=0A= + /*=0A= + * Install a unique fd for each memslot so that the fd=0A= + * can be closed when the region is deleted without=0A= + * needing to track if the fd is owned by the framework=0A= + * or by the caller.=0A= + */=0A= + guest_memfd =3D kvm_dup(guest_memfd);=0A= + }=0A= +=0A= + if (guest_memfd > 0) {=0A= + flags |=3D KVM_MEM_GUEST_MEMFD;=0A= +=0A= + region->region.guest_memfd =3D guest_memfd;=0A= + region->region.guest_memfd_offset =3D guest_memfd_offset;=0A= + } else {=0A= + region->region.guest_memfd =3D -1;=0A= + }=0A= +=0A= /*=0A= * When using THP mmap is not guaranteed to returned a hugepage aligned= =0A= * address so we have to pad the mmap. Padding is not needed for HugeTLB= =0A= @@ -1028,10 +1055,13 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_back= ing_src_type src_type,=0A= if (alignment > 1)=0A= region->mmap_size +=3D alignment;=0A= =0A= - region->fd =3D -1;=0A= - if (backing_src_is_shared(src_type))=0A= + if (backing_src_is_guest_memfd(src_type))=0A= + region->fd =3D guest_memfd;=0A= + else if (backing_src_is_shared(src_type))=0A= region->fd =3D kvm_memfd_alloc(region->mmap_size,=0A= src_type =3D=3D VM_MEM_SRC_SHARED_HUGETLB);=0A= + else=0A= + region->fd =3D -1;=0A= =0A= region->mmap_start =3D kvm_mmap(region->mmap_size, PROT_READ | PROT_WRITE= ,=0A= vm_mem_backing_src_alias(src_type)->flag,=0A= @@ -1056,33 +1086,6 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backi= ng_src_type src_type,=0A= }=0A= =0A= region->backing_src_type =3D src_type;=0A= -=0A= - if (guest_memfd < 0) {=0A= - if (flags & KVM_MEM_GUEST_MEMFD) {=0A= - uint32_t guest_memfd_flags =3D 0;=0A= - TEST_ASSERT(!guest_memfd_offset,=0A= - "Offset must be zero when creating new guest_memfd");=0A= - guest_memfd =3D vm_create_guest_memfd(vm, mem_size, guest_memfd_flags);= =0A= - }=0A= - } else {=0A= - /*=0A= - * Install a unique fd for each memslot so that the fd=0A= - * can be closed when the region is deleted without=0A= - * needing to track if the fd is owned by the framework=0A= - * or by the caller.=0A= - */=0A= - guest_memfd =3D kvm_dup(guest_memfd);=0A= - }=0A= -=0A= - if (guest_memfd > 0) {=0A= - flags |=3D KVM_MEM_GUEST_MEMFD;=0A= -=0A= - region->region.guest_memfd =3D guest_memfd;=0A= - region->region.guest_memfd_offset =3D guest_memfd_offset;=0A= - } else {=0A= - region->region.guest_memfd =3D -1;=0A= - }=0A= -=0A= region->unused_phy_pages =3D sparsebit_alloc();=0A= if (vm_arch_has_protected_memory(vm))=0A= region->protected_phy_pages =3D sparsebit_alloc();=0A= diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/se= lftests/kvm/lib/test_util.c=0A= index 8a1848586a85..ce9fe0271515 100644=0A= --- a/tools/testing/selftests/kvm/lib/test_util.c=0A= +++ b/tools/testing/selftests/kvm/lib/test_util.c=0A= @@ -306,6 +306,14 @@ const struct vm_mem_backing_src_alias *vm_mem_backing_= src_alias(uint32_t i)=0A= */=0A= .flag =3D MAP_SHARED,=0A= },=0A= + [VM_MEM_SRC_GUEST_MEMFD] =3D {=0A= + .name =3D "guest_memfd",=0A= + .flag =3D MAP_SHARED,=0A= + },=0A= + [VM_MEM_SRC_GUEST_MEMFD_NO_DIRECT_MAP] =3D {=0A= + .name =3D "guest_memfd_no_direct_map",=0A= + .flag =3D MAP_SHARED,=0A= + }=0A= };=0A= _Static_assert(ARRAY_SIZE(aliases) =3D=3D NUM_SRC_TYPES,=0A= "Missing new backing src types?");=0A= -- =0A= 2.50.1=0A= =0A=