[PATCH v2 144/144] KVM: selftests: Sanity check input to ioctls() at build time

Sean Christopherson
2022-06-03T01:01:23Z

Add a static assert to the KVM/VM/vCPU ioctl() helpers to verify that the
size of the argument provided matches the expected size of the IOCTL.
Because ioctl() ultimately takes a "void *", it's all too easy to pass in
garbage and not detect the error until runtime. E.g. while working on a
CPUID rework, selftests happily compiled when vcpu_set_cpuid()
unintentionally passed the cpuid() function as the parameter to ioctl()
(a local "cpuid" parameter was removed, but its use was not replaced with
"vcpu->cpuid" as intended).

Tweak a variety of benign issues that aren't compatible with the sanity
check, e.g. passing a non-pointer for ioctls().

Note, static_assert() requires a string on older versions of GCC. Feed
it an empty string to make the compiler happy.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
.../selftests/kvm/include/kvm_util_base.h | 61 +++++++++++++------
.../selftests/kvm/lib/aarch64/processor.c | 2 +-
tools/testing/selftests/kvm/lib/guest_modes.c | 2 +-
tools/testing/selftests/kvm/lib/kvm_util.c | 29 +--------
tools/testing/selftests/kvm/s390x/resets.c | 6 +-
.../selftests/kvm/x86_64/mmio_warning_test.c | 2 +-
.../kvm/x86_64/pmu_event_filter_test.c | 2 +-
.../selftests/kvm/x86_64/xen_shinfo_test.c | 6 +-
8 files changed, 56 insertions(+), 54 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 04ddab322b6b..0eaf0c9b7612 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -180,29 +180,56 @@ static inline bool kvm_has_cap(long cap)
#define __KVM_IOCTL_ERROR(_name, _ret) __KVM_SYSCALL_ERROR(_name, _ret)
#define KVM_IOCTL_ERROR(_ioctl, _ret) __KVM_IOCTL_ERROR(#_ioctl, _ret)

-#define __kvm_ioctl(kvm_fd, cmd, arg) \
- ioctl(kvm_fd, cmd, arg)
+#define kvm_do_ioctl(fd, cmd, arg) \
+({ \
+ static_assert(!_IOC_SIZE(cmd) || sizeof(*arg) == _IOC_SIZE(cmd), ""); \
+ ioctl(fd, cmd, arg); \
+})

-static inline void _kvm_ioctl(int kvm_fd, unsigned long cmd, const char *name,
- void *arg)
-{
- int ret = __kvm_ioctl(kvm_fd, cmd, arg);
+#define __kvm_ioctl(kvm_fd, cmd, arg) \
+ kvm_do_ioctl(kvm_fd, cmd, arg)

- TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret));
-}
+
+#define _kvm_ioctl(kvm_fd, cmd, name, arg) \
+({ \
+ int ret = __kvm_ioctl(kvm_fd, cmd, arg); \
+ \
+ TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret)); \
+})

#define kvm_ioctl(kvm_fd, cmd, arg) \
_kvm_ioctl(kvm_fd, cmd, #cmd, arg)

-int __vm_ioctl(struct kvm_vm *vm, unsigned long cmd, void *arg);
-void _vm_ioctl(struct kvm_vm *vm, unsigned long cmd, const char *name, void *arg);
-#define vm_ioctl(vm, cmd, arg) _vm_ioctl(vm, cmd, #cmd, arg)
-
-int __vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long cmd,
- void *arg);
-void _vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long cmd,
- const char *name, void *arg);
-#define vcpu_ioctl(vcpu, cmd, arg) \
+#define __vm_ioctl(vm, cmd, arg) \
+({ \
+ static_assert(sizeof(*(vm)) == sizeof(struct kvm_vm), ""); \
+ kvm_do_ioctl((vm)->fd, cmd, arg); \
+})
+
+#define _vm_ioctl(vcpu, cmd, name, arg) \
+({ \
+ int ret = __vm_ioctl(vcpu, cmd, arg); \
+ \
+ TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret)); \
+})
+
+#define vm_ioctl(vm, cmd, arg) \
+ _vm_ioctl(vm, cmd, #cmd, arg)
+
+#define __vcpu_ioctl(vcpu, cmd, arg) \
+({ \
+ static_assert(sizeof(*(vcpu)) == sizeof(struct kvm_vcpu), ""); \
+ kvm_do_ioctl((vcpu)->fd, cmd, arg); \
+})
+
+#define _vcpu_ioctl(vcpu, cmd, name, arg) \
+({ \
+ int ret = __vcpu_ioctl(vcpu, cmd, arg); \
+ \
+ TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret)); \
+})
+
+#define vcpu_ioctl(vcpu, cmd, arg) \
_vcpu_ioctl(vcpu, cmd, #cmd, arg)

/*
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 6bd27782f00c..6f5551368944 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -472,7 +472,7 @@ void aarch64_get_supported_page_sizes(uint32_t ipa,
};

kvm_fd = open_kvm_dev_path_or_exit();
- vm_fd = __kvm_ioctl(kvm_fd, KVM_CREATE_VM, ipa);
+ vm_fd = __kvm_ioctl(kvm_fd, KVM_CREATE_VM, (void *)(unsigned long)ipa);
TEST_ASSERT(vm_fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VM, vm_fd));

vcpu_fd = ioctl(vm_fd, KVM_CREATE_VCPU, 0);
diff --git a/tools/testing/selftests/kvm/lib/guest_modes.c b/tools/testing/selftests/kvm/lib/guest_modes.c
index 0be56c63aed6..99a575bbbc52 100644
--- a/tools/testing/selftests/kvm/lib/guest_modes.c
+++ b/tools/testing/selftests/kvm/lib/guest_modes.c
@@ -65,7 +65,7 @@ void guest_modes_append_default(void)
struct kvm_s390_vm_cpu_processor info;

kvm_fd = open_kvm_dev_path_or_exit();
- vm_fd = __kvm_ioctl(kvm_fd, KVM_CREATE_VM, 0);
+ vm_fd = __kvm_ioctl(kvm_fd, KVM_CREATE_VM, NULL);
kvm_device_attr_get(vm_fd, KVM_S390_VM_CPU_MODEL,
KVM_S390_VM_CPU_PROCESSOR, &info);
close(vm_fd);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 603a6d529357..f0300767df16 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -72,7 +72,7 @@ unsigned int kvm_check_cap(long cap)
int kvm_fd;

kvm_fd = open_kvm_dev_path_or_exit();
- ret = __kvm_ioctl(kvm_fd, KVM_CHECK_EXTENSION, cap);
+ ret = __kvm_ioctl(kvm_fd, KVM_CHECK_EXTENSION, (void *)cap);
TEST_ASSERT(ret >= 0, KVM_IOCTL_ERROR(KVM_CHECK_EXTENSION, ret));

close(kvm_fd);
@@ -92,7 +92,7 @@ static void vm_open(struct kvm_vm *vm)

TEST_REQUIRE(kvm_has_cap(KVM_CAP_IMMEDIATE_EXIT));

- vm->fd = __kvm_ioctl(vm->kvm_fd, KVM_CREATE_VM, vm->type);
+ vm->fd = __kvm_ioctl(vm->kvm_fd, KVM_CREATE_VM, (void *)vm->type);
TEST_ASSERT(vm->fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_VM, vm->fd));
}

@@ -1449,19 +1449,6 @@ struct kvm_reg_list *vcpu_get_reg_list(struct kvm_vcpu *vcpu)
return reg_list;
}

-int __vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long cmd, void *arg)
-{
- return ioctl(vcpu->fd, cmd, arg);
-}
-
-void _vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long cmd, const char *name,
- void *arg)
-{
- int ret = __vcpu_ioctl(vcpu, cmd, arg);
-
- TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret));
-}
-
void *vcpu_map_dirty_ring(struct kvm_vcpu *vcpu)
{
uint32_t page_size = vcpu->vm->page_size;
@@ -1491,18 +1478,6 @@ void *vcpu_map_dirty_ring(struct kvm_vcpu *vcpu)
return vcpu->dirty_gfns;
}

-int __vm_ioctl(struct kvm_vm *vm, unsigned long cmd, void *arg)
-{
- return ioctl(vm->fd, cmd, arg);
-}
-
-void _vm_ioctl(struct kvm_vm *vm, unsigned long cmd, const char *name, void *arg)
-{
- int ret = __vm_ioctl(vm, cmd, arg);
-
- TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(name, ret));
-}
-
/*
* Device Ioctl
*/
diff --git a/tools/testing/selftests/kvm/s390x/resets.c b/tools/testing/selftests/kvm/s390x/resets.c
index 4ba866047401..359fd18f473b 100644
--- a/tools/testing/selftests/kvm/s390x/resets.c
+++ b/tools/testing/selftests/kvm/s390x/resets.c
@@ -224,7 +224,7 @@ static void test_normal(void)

inject_irq(vcpu);

- vcpu_ioctl(vcpu, KVM_S390_NORMAL_RESET, 0);
+ vcpu_ioctl(vcpu, KVM_S390_NORMAL_RESET, NULL);

/* must clears */
assert_normal(vcpu);
@@ -247,7 +247,7 @@ static void test_initial(void)

inject_irq(vcpu);

- vcpu_ioctl(vcpu, KVM_S390_INITIAL_RESET, 0);
+ vcpu_ioctl(vcpu, KVM_S390_INITIAL_RESET, NULL);

/* must clears */
assert_normal(vcpu);
@@ -270,7 +270,7 @@ static void test_clear(void)

inject_irq(vcpu);

- vcpu_ioctl(vcpu, KVM_S390_CLEAR_RESET, 0);
+ vcpu_ioctl(vcpu, KVM_S390_CLEAR_RESET, NULL);

/* must clears */
assert_normal(vcpu);
diff --git a/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c b/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c
index 0e4590afd0e1..fb02581953a3 100644
--- a/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c
+++ b/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c
@@ -59,7 +59,7 @@ void test(void)

kvm = open("/dev/kvm", O_RDWR);
TEST_ASSERT(kvm != -1, "failed to open /dev/kvm");
- kvmvm = __kvm_ioctl(kvm, KVM_CREATE_VM, 0);
+ kvmvm = __kvm_ioctl(kvm, KVM_CREATE_VM, NULL);
TEST_ASSERT(kvmvm > 0, KVM_IOCTL_ERROR(KVM_CREATE_VM, kvmvm));
kvmcpu = ioctl(kvmvm, KVM_CREATE_VCPU, 0);
TEST_ASSERT(kvmcpu != -1, KVM_IOCTL_ERROR(KVM_CREATE_VCPU, kvmcpu));
diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
index de9ee00d84cf..66930384ef97 100644
--- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
+++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
@@ -266,7 +266,7 @@ static void test_without_filter(struct kvm_vcpu *vcpu)
static uint64_t test_with_filter(struct kvm_vcpu *vcpu,
struct kvm_pmu_event_filter *f)
{
- vm_ioctl(vcpu->vm, KVM_SET_PMU_EVENT_FILTER, (void *)f);
+ vm_ioctl(vcpu->vm, KVM_SET_PMU_EVENT_FILTER, f);
return run_vcpu_to_sync(vcpu);
}

diff --git a/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c b/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c
index bdcb28186ccc..a4a78637c35a 100644
--- a/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c
+++ b/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c
@@ -472,7 +472,7 @@ int main(int argc, char *argv[])
irq_routes.entries[1].u.xen_evtchn.vcpu = vcpu->id;
irq_routes.entries[1].u.xen_evtchn.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;

- vm_ioctl(vm, KVM_SET_GSI_ROUTING, &irq_routes);
+ vm_ioctl(vm, KVM_SET_GSI_ROUTING, &irq_routes.info);

struct kvm_irqfd ifd = { };

@@ -716,7 +716,7 @@ int main(int argc, char *argv[])
if (verbose)
printf("Testing restored oneshot timer\n");

- tmr.u.timer.expires_ns = rs->state_entry_time + 100000000,
+ tmr.u.timer.expires_ns = rs->state_entry_time + 100000000;
vcpu_ioctl(vcpu, KVM_XEN_VCPU_SET_ATTR, &tmr);
evtchn_irq_expected = true;
alarm(1);
@@ -743,7 +743,7 @@ int main(int argc, char *argv[])
if (verbose)
printf("Testing SCHEDOP_poll wake on masked event\n");

- tmr.u.timer.expires_ns = rs->state_entry_time + 100000000,
+ tmr.u.timer.expires_ns = rs->state_entry_time + 100000000;
vcpu_ioctl(vcpu, KVM_XEN_VCPU_SET_ATTR, &tmr);
alarm(1);
break;
--
2.36.1.255.ge46751e96f-goog