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Fri, 14 Nov 2025 15:18:54 +0000 (UTC) X-Farcaster-Flow-ID: 37f9e9e0-3a84-4a33-b291-c598729a7c67 Received: from EX19D022EUC003.ant.amazon.com (10.252.51.167) by EX19MTAEUA001.ant.amazon.com (10.252.50.192) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.29; Fri, 14 Nov 2025 15:18:54 +0000 Received: from EX19D022EUC002.ant.amazon.com (10.252.51.137) by EX19D022EUC003.ant.amazon.com (10.252.51.167) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.29; Fri, 14 Nov 2025 15:18:54 +0000 Received: from EX19D022EUC002.ant.amazon.com ([fe80::bd:307b:4d3a:7d80]) by EX19D022EUC002.ant.amazon.com ([fe80::bd:307b:4d3a:7d80%3]) with mapi id 15.02.2562.029; Fri, 14 Nov 2025 15:18:53 +0000 From: "Kalyazin, Nikita" To: "pbonzini@redhat.com" , "shuah@kernel.org" CC: "kvm@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "seanjc@google.com" , "david@kernel.org" , "jthoughton@google.com" , "ackerleytng@google.com" , "vannapurve@google.com" , "jackmanb@google.com" , "patrick.roy@linux.dev" , "Thomson, Jack" , "Itazuri, Takahiro" , "Manwaring, Derek" , "Cali, Marco" , "Kalyazin, Nikita" Subject: [PATCH v7 2/2] KVM: selftests: update guest_memfd write tests Thread-Topic: [PATCH v7 2/2] KVM: selftests: update guest_memfd write tests Thread-Index: AQHcVXn8AzrsKiqAcEa0iTWGk+wWoA== Date: Fri, 14 Nov 2025 15:18:53 +0000 Message-ID: <20251114151828.98165-3-kalyazin@amazon.com> References: <20251114151828.98165-1-kalyazin@amazon.com> In-Reply-To: <20251114151828.98165-1-kalyazin@amazon.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: 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 Content-Type: text/plain; charset="utf-8" From: Nikita Kalyazin This is to reflect that the write syscall is now implemented for guest_memfd. Signed-off-by: Nikita Kalyazin --- .../testing/selftests/kvm/guest_memfd_test.c | 58 +++++++++++++++++-- 1 file changed, 52 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing= /selftests/kvm/guest_memfd_test.c index e7d9aeb418d3..ef3e92e18ee6 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -24,18 +24,57 @@ =20 static size_t page_size; =20 -static void test_file_read_write(int fd, size_t total_size) +static void test_file_read(int fd, size_t total_size) { char buf[64]; =20 TEST_ASSERT(read(fd, buf, sizeof(buf)) < 0, "read on a guest_mem fd should fail"); - TEST_ASSERT(write(fd, buf, sizeof(buf)) < 0, - "write on a guest_mem fd should fail"); TEST_ASSERT(pread(fd, buf, sizeof(buf), 0) < 0, "pread on a guest_mem fd should fail"); - TEST_ASSERT(pwrite(fd, buf, sizeof(buf), 0) < 0, - "pwrite on a guest_mem fd should fail"); +} + +static void test_write_supported(int fd, size_t total_size) +{ + size_t page_size =3D getpagesize(); + void *buf =3D NULL; + int ret; + + ret =3D posix_memalign(&buf, page_size, total_size); + TEST_ASSERT_EQ(ret, 0); + + ret =3D pwrite(fd, buf, page_size, total_size); + TEST_ASSERT(ret =3D=3D -1, "writing past the file size on a guest_mem fd = should fail"); + TEST_ASSERT_EQ(errno, EINVAL); + + ret =3D pwrite(fd, buf, 1, 0); + TEST_ASSERT(ret =3D=3D -1, "writing an unaligned count a guest_mem fd sho= uld fail"); + TEST_ASSERT_EQ(errno, EINVAL); + + ret =3D pwrite(fd, buf, page_size, 1); + TEST_ASSERT(ret =3D=3D -1, "writing to an unaligned offset a guest_mem fd= should fail"); + TEST_ASSERT_EQ(errno, EINVAL); + + ret =3D pwrite(fd, buf, page_size, 0); + TEST_ASSERT(ret =3D=3D page_size, "write on a guest_mem fd should succeed= "); + + free(buf); +} + +static void test_write_not_supported(int fd, size_t total_size) +{ + size_t page_size =3D getpagesize(); + void *buf =3D NULL; + int ret; + + ret =3D posix_memalign(&buf, page_size, total_size); + TEST_ASSERT_EQ(ret, 0); + + ret =3D pwrite(fd, buf, page_size, 0); + TEST_ASSERT(ret =3D=3D -1, "write on guest_mem fd should fail"); + TEST_ASSERT_EQ(errno, ENODEV); + + free(buf); } =20 static void test_mmap_cow(int fd, size_t size) @@ -267,7 +306,7 @@ static void __test_guest_memfd(struct kvm_vm *vm, uint6= 4_t flags) test_create_guest_memfd_multiple(vm); test_create_guest_memfd_invalid_sizes(vm, flags); =20 - gmem_test(file_read_write, vm, flags); + gmem_test(file_read, vm, flags); =20 if (flags & GUEST_MEMFD_FLAG_MMAP) { if (flags & GUEST_MEMFD_FLAG_INIT_SHARED) { @@ -282,6 +321,11 @@ static void __test_guest_memfd(struct kvm_vm *vm, uint= 64_t flags) gmem_test(mmap_not_supported, vm, flags); } =20 + if (flags & GUEST_MEMFD_FLAG_WRITE) + gmem_test(write_supported, vm, flags); + else + gmem_test(write_not_supported, vm, flags); + gmem_test(file_size, vm, flags); gmem_test(fallocate, vm, flags); gmem_test(invalid_punch_hole, vm, flags); @@ -299,6 +343,8 @@ static void test_guest_memfd(unsigned long vm_type) flags =3D vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS); if (flags & GUEST_MEMFD_FLAG_MMAP) __test_guest_memfd(vm, GUEST_MEMFD_FLAG_MMAP); + if (flags & GUEST_MEMFD_FLAG_WRITE) + __test_guest_memfd(vm, GUEST_MEMFD_FLAG_WRITE); =20 /* MMAP should always be supported if INIT_SHARED is supported. */ if (flags & GUEST_MEMFD_FLAG_INIT_SHARED) --=20 2.50.1