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AJvYcCVIRSUOapmbYCeniguPQfdINUtEXypLMUNdBAi/Nn+XHp3NES9EKGgtjmxeB06O1SAgrN0e7tM+FbtuME/g@vger.kernel.org X-Gm-Message-State: AOJu0YxZqPaMC7nmAKuDJu7rpOlV41VCTVzt+FGv1/kvHvLhhqHxZtRo 3YSr6bD8YLGz2A1N+bILdcpdhiMPkI/+jZ78LifYohIsefuR6aHdaYc3qsgvveFQZAUg0OTUCXP 6UBPexYSQQZRqe6AgM6SnkA== X-Google-Smtp-Source: AGHT+IHC0afSzx4CRGLb+NEtt5FopkBc14R3Tsx3Oo5v/U8eDsNNnam5RHpBwQ1p1qHPCM63buWzU71Ko18fm+qY7w== X-Received: from pjbnd11.prod.google.com ([2002:a17:90b:4ccb:b0:2fa:a101:743]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:2d4f:b0:30a:3e8e:12cd with SMTP id 98e67ed59e1d1-30e51914e56mr638587a91.22.1747266191346; Wed, 14 May 2025 16:43:11 -0700 (PDT) Date: Wed, 14 May 2025 16:41:48 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.49.0.1045.g170613ef41-goog Message-ID: <3d2f49b409f1d6564eaff49494789908eb9b74e5.1747264138.git.ackerleytng@google.com> Subject: [RFC PATCH v2 09/51] KVM: selftests: Test faulting with respect to GUEST_MEMFD_FLAG_INIT_PRIVATE From: Ackerley Tng To: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-fsdevel@vger.kernel.org Cc: ackerleytng@google.com, aik@amd.com, ajones@ventanamicro.com, akpm@linux-foundation.org, amoorthy@google.com, anthony.yznaga@oracle.com, anup@brainfault.org, aou@eecs.berkeley.edu, bfoster@redhat.com, binbin.wu@linux.intel.com, brauner@kernel.org, catalin.marinas@arm.com, chao.p.peng@intel.com, chenhuacai@kernel.org, dave.hansen@intel.com, david@redhat.com, dmatlack@google.com, dwmw@amazon.co.uk, erdemaktas@google.com, fan.du@intel.com, fvdl@google.com, graf@amazon.com, haibo1.xu@intel.com, hch@infradead.org, hughd@google.com, ira.weiny@intel.com, isaku.yamahata@intel.com, jack@suse.cz, james.morse@arm.com, jarkko@kernel.org, jgg@ziepe.ca, jgowans@amazon.com, jhubbard@nvidia.com, jroedel@suse.de, jthoughton@google.com, jun.miao@intel.com, kai.huang@intel.com, keirf@google.com, kent.overstreet@linux.dev, kirill.shutemov@intel.com, liam.merwick@oracle.com, maciej.wieczor-retman@intel.com, mail@maciej.szmigiero.name, maz@kernel.org, mic@digikod.net, michael.roth@amd.com, mpe@ellerman.id.au, muchun.song@linux.dev, nikunj@amd.com, nsaenz@amazon.es, oliver.upton@linux.dev, palmer@dabbelt.com, pankaj.gupta@amd.com, paul.walmsley@sifive.com, pbonzini@redhat.com, pdurrant@amazon.co.uk, peterx@redhat.com, pgonda@google.com, pvorel@suse.cz, qperret@google.com, quic_cvanscha@quicinc.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, quic_svaddagi@quicinc.com, quic_tsoni@quicinc.com, richard.weiyang@gmail.com, rick.p.edgecombe@intel.com, rientjes@google.com, roypat@amazon.co.uk, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, steven.price@arm.com, steven.sistare@oracle.com, suzuki.poulose@arm.com, tabba@google.com, thomas.lendacky@amd.com, usama.arif@bytedance.com, vannapurve@google.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, vkuznets@redhat.com, wei.w.wang@intel.com, will@kernel.org, willy@infradead.org, xiaoyao.li@intel.com, yan.y.zhao@intel.com, yilun.xu@intel.com, yuzenghui@huawei.com, zhiquan1.li@intel.com Content-Type: text/plain; charset="UTF-8" Test that faulting is denied when guest_memfd's shareability is initialized as private with GUEST_MEMFD_FLAG_INIT_PRIVATE and allowed if the flag is not specified. Signed-off-by: Ackerley Tng Co-developed-by: Fuad Tabba Signed-off-by: Fuad Tabba Change-Id: Id93d4683b36fc5a9c924458d26f0525baed26435 --- .../testing/selftests/kvm/guest_memfd_test.c | 112 +++++++++++++++--- 1 file changed, 97 insertions(+), 15 deletions(-) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 51d88acdf072..1e79382fd830 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "kvm_util.h" #include "test_util.h" @@ -34,7 +35,7 @@ static void test_file_read_write(int fd) "pwrite on a guest_mem fd should fail"); } -static void test_mmap_allowed(int fd, size_t page_size, size_t total_size) +static void test_faulting_allowed(int fd, size_t page_size, size_t total_size) { const char val = 0xaa; char *mem; @@ -65,6 +66,53 @@ static void test_mmap_allowed(int fd, size_t page_size, size_t total_size) TEST_ASSERT(!ret, "munmap should succeed"); } +static void assert_not_faultable(char *address) +{ + pid_t child_pid; + + child_pid = fork(); + TEST_ASSERT(child_pid != -1, "fork failed"); + + if (child_pid == 0) { + *address = 'A'; + TEST_FAIL("Child should have exited with a signal"); + } else { + int status; + + waitpid(child_pid, &status, 0); + + TEST_ASSERT(WIFSIGNALED(status), + "Child should have exited with a signal"); + TEST_ASSERT_EQ(WTERMSIG(status), SIGBUS); + } +} + +static void test_faulting_sigbus(int fd, size_t total_size) +{ + char *mem; + int ret; + + mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmaping() guest memory should pass."); + + assert_not_faultable(mem); + + ret = munmap(mem, total_size); + TEST_ASSERT(!ret, "munmap should succeed"); +} + +static void test_mmap_allowed(int fd, size_t total_size) +{ + char *mem; + int ret; + + mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmaping() guest memory should pass."); + + ret = munmap(mem, total_size); + TEST_ASSERT(!ret, "munmap should succeed"); +} + static void test_mmap_denied(int fd, size_t page_size, size_t total_size) { char *mem; @@ -364,40 +412,74 @@ static void test_bind_guest_memfd_wrt_userspace_addr(struct kvm_vm *vm) close(fd); } -static void test_with_type(unsigned long vm_type, uint64_t guest_memfd_flags, - bool expect_mmap_allowed) +static void test_guest_memfd_features(struct kvm_vm *vm, size_t page_size, + uint64_t guest_memfd_flags, + bool expect_mmap_allowed, + bool expect_faulting_allowed) { - struct kvm_vm *vm; size_t total_size; - size_t page_size; int fd; - if (!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(vm_type))) - return; - - page_size = getpagesize(); total_size = page_size * 4; - vm = vm_create_barebones_type(vm_type); + if (expect_faulting_allowed) + TEST_REQUIRE(expect_mmap_allowed); - test_create_guest_memfd_multiple(vm); - test_bind_guest_memfd_wrt_userspace_addr(vm); test_create_guest_memfd_invalid_sizes(vm, guest_memfd_flags, page_size); fd = vm_create_guest_memfd(vm, total_size, guest_memfd_flags); test_file_read_write(fd); - if (expect_mmap_allowed) - test_mmap_allowed(fd, page_size, total_size); - else + if (expect_mmap_allowed) { + test_mmap_allowed(fd, total_size); + + if (expect_faulting_allowed) + test_faulting_allowed(fd, page_size, total_size); + else + test_faulting_sigbus(fd, total_size); + } else { test_mmap_denied(fd, page_size, total_size); + } test_file_size(fd, page_size, total_size); test_fallocate(fd, page_size, total_size); test_invalid_punch_hole(fd, page_size, total_size); close(fd); +} + +static void test_with_type(unsigned long vm_type, uint64_t guest_memfd_flags, + bool expect_mmap_allowed) +{ + struct kvm_vm *vm; + size_t page_size; + + if (!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(vm_type))) + return; + + vm = vm_create_barebones_type(vm_type); + + test_create_guest_memfd_multiple(vm); + test_bind_guest_memfd_wrt_userspace_addr(vm); + + page_size = getpagesize(); + if (guest_memfd_flags & GUEST_MEMFD_FLAG_SUPPORT_SHARED) { + test_guest_memfd_features(vm, page_size, guest_memfd_flags, + expect_mmap_allowed, true); + + if (kvm_has_cap(KVM_CAP_GMEM_CONVERSION)) { + uint64_t flags = guest_memfd_flags | + GUEST_MEMFD_FLAG_INIT_PRIVATE; + + test_guest_memfd_features(vm, page_size, flags, + expect_mmap_allowed, false); + } + } else { + test_guest_memfd_features(vm, page_size, guest_memfd_flags, + expect_mmap_allowed, false); + } + kvm_vm_release(vm); } -- 2.49.0.1045.g170613ef41-goog