| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20250828153049.3922-3-kalyazin@amazon.com>
Date: Thu, 28 Aug 2025 15:31:12 +0000
From: "Kalyazin, Nikita" <kalyazin@...zon.co.uk>
To: "pbonzini@...hat.com" <pbonzini@...hat.com>, "shuah@...nel.org"
<shuah@...nel.org>
CC: "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"michael.day@....com" <michael.day@....com>, "david@...hat.com"
<david@...hat.com>, "jthoughton@...gle.com" <jthoughton@...gle.com>, "Roy,
Patrick" <roypat@...zon.co.uk>, "Thomson, Jack" <jackabt@...zon.co.uk>,
"Manwaring, Derek" <derekmn@...zon.com>, "Cali, Marco"
<xmarcalx@...zon.co.uk>, "Kalyazin, Nikita" <kalyazin@...zon.co.uk>
Subject: [PATCH v4 2/2] KVM: selftests: update guest_memfd write tests
This is to reflect that the write syscall is now implemented for
guest_memfd.
Signed-off-by: Nikita Kalyazin <kalyazin@...zon.com>
---
.../testing/selftests/kvm/guest_memfd_test.c | 85 +++++++++++++++++--
1 file changed, 79 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index b3ca6737f304..7217a3232055 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -24,18 +24,90 @@
#include "test_util.h"
#include "ucall_common.h"
-static void test_file_read_write(int fd)
+static void test_file_read(int fd)
{
char buf[64];
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_file_write(int fd, size_t total_size)
+{
+ size_t page_size = getpagesize();
+ void *buf = NULL;
+ int ret;
+
+ ret = posix_memalign(&buf, page_size, total_size);
+ TEST_ASSERT_EQ(ret, 0);
+
+ /* Check arguments correctness checks work as expected */
+
+ ret = pwrite(fd, buf, page_size - 1, 0);
+ TEST_ASSERT(ret == -1, "write unaligned count on a guest_mem fd should fail");
+ TEST_ASSERT_EQ(errno, EINVAL);
+
+ ret = pwrite(fd, buf, page_size, 1);
+ TEST_ASSERT(ret == -1, "write unaligned offset on a guest_mem fd should fail");
+ TEST_ASSERT_EQ(errno, EINVAL);
+
+ ret = pwrite(fd, buf, page_size, total_size);
+ TEST_ASSERT(ret == -1, "writing past the file size on a guest_mem fd should fail");
+ TEST_ASSERT_EQ(errno, EINVAL);
+
+ ret = pwrite(fd, NULL, page_size, 0);
+ TEST_ASSERT(ret == -1, "supplying a NULL buffer when writing a guest_mem fd should fail");
+ TEST_ASSERT_EQ(errno, EFAULT);
+
+ /* Check double population is not allowed */
+
+ ret = pwrite(fd, buf, page_size, 0);
+ TEST_ASSERT(ret == page_size, "page-aligned write on a guest_mem fd should succeed");
+
+ ret = pwrite(fd, buf, page_size, 0);
+ TEST_ASSERT(ret == -1, "write on already populated guest_mem fd should fail");
+ TEST_ASSERT_EQ(errno, ENOSPC);
+
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ /* Check population is allowed again after punching a hole */
+
+ ret = pwrite(fd, buf, page_size, 0);
+ TEST_ASSERT(ret == page_size, "page-aligned write on a punched guest_mem fd should succeed");
+
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ /* Check population of already allocated memory is allowed */
+
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, page_size);
+ TEST_ASSERT(!ret, "fallocate with aligned offset and size should succeed");
+
+ ret = pwrite(fd, buf, page_size, 0);
+ TEST_ASSERT(ret == page_size, "write on a preallocated guest_mem fd should succeed");
+
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ /* Check population works until an already populated page is encountered */
+
+ ret = pwrite(fd, buf, total_size, 0);
+ TEST_ASSERT(ret == total_size, "page-aligned write on a guest_mem fd should succeed");
+
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+ ret = pwrite(fd, buf, total_size, 0);
+ TEST_ASSERT(ret == page_size, "write on a guest_mem fd should not overwrite data");
+
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, total_size);
+ TEST_ASSERT(!ret, "fallocate(PUNCH_HOLE) should succeed");
+
+
+ free(buf);
}
static void test_mmap_supported(int fd, size_t page_size, size_t total_size)
@@ -281,7 +353,8 @@ static void test_guest_memfd(unsigned long vm_type)
fd = vm_create_guest_memfd(vm, total_size, flags);
- test_file_read_write(fd);
+ test_file_read(fd);
+ test_file_write(fd, total_size);
if (flags & GUEST_MEMFD_FLAG_MMAP) {
test_mmap_supported(fd, page_size, total_size);
--
2.50.1
Powered by blists - more mailing lists