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* [PATCH v2] KVM: selftests: Print a message if /dev/kvm is missing
@ 2021-05-08  0:28 David Matlack
  2021-05-10  6:28 ` Andrew Jones
  0 siblings, 1 reply; 2+ messages in thread
From: David Matlack @ 2021-05-08  0:28 UTC (permalink / raw)
  To: kvm; +Cc: Paolo Bonzini, Andrew Jones, Aaron Lewis, David Matlack

If a KVM selftest is run on a machine without /dev/kvm, it will exit
silently. Make it easy to tell what's happening by printing an error
message.

Opportunistically consolidate all codepaths that open /dev/kvm into a
single function so they all print the same message.

This slightly changes the semantics of vm_is_unrestricted_guest() by
changing a TEST_ASSERT() to exit(KSFT_SKIP). However
vm_is_unrestricted_guest() is only called in one place
(x86_64/mmio_warning_test.c) and that is to determine if the test should
be skipped or not.

Signed-off-by: David Matlack <dmatlack@google.com>
---
 .../testing/selftests/kvm/include/kvm_util.h  |  1 +
 tools/testing/selftests/kvm/lib/kvm_util.c    | 39 ++++++++++++-------
 .../selftests/kvm/lib/x86_64/processor.c      | 16 ++------
 .../kvm/x86_64/get_msr_index_features.c       |  8 +---
 4 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index a8f022794ce3..401393a8c2b7 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -77,6 +77,7 @@ struct vm_guest_mode_params {
 };
 extern const struct vm_guest_mode_params vm_guest_mode_params[];
 
+int open_kvm_dev_path_or_exit(int flags);
 int kvm_check_cap(long cap);
 int vm_enable_cap(struct kvm_vm *vm, struct kvm_enable_cap *cap);
 int vcpu_enable_cap(struct kvm_vm *vm, uint32_t vcpu_id,
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index fc83f6c5902d..10d488f83e3a 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -31,6 +31,27 @@ static void *align(void *x, size_t size)
 	return (void *) (((size_t) x + mask) & ~mask);
 }
 
+/* Open KVM_DEV_PATH if available, otherwise exit the entire program.
+ *
+ * Input Args:
+ *   flags - The flags to pass when opening KVM_DEV_PATH.
+ *
+ * Return:
+ *   The opened file descriptor of /dev/kvm.
+ */
+int open_kvm_dev_path_or_exit(int flags)
+{
+	int fd;
+
+	fd = open(KVM_DEV_PATH, flags);
+	if (fd < 0) {
+		print_skip("%s not available", KVM_DEV_PATH);
+		exit(KSFT_SKIP);
+	}
+
+	return fd;
+}
+
 /*
  * Capability
  *
@@ -52,10 +73,7 @@ int kvm_check_cap(long cap)
 	int ret;
 	int kvm_fd;
 
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
-
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 	ret = ioctl(kvm_fd, KVM_CHECK_EXTENSION, cap);
 	TEST_ASSERT(ret != -1, "KVM_CHECK_EXTENSION IOCTL failed,\n"
 		"  rc: %i errno: %i", ret, errno);
@@ -128,9 +146,7 @@ void vm_enable_dirty_ring(struct kvm_vm *vm, uint32_t ring_size)
 
 static void vm_open(struct kvm_vm *vm, int perm)
 {
-	vm->kvm_fd = open(KVM_DEV_PATH, perm);
-	if (vm->kvm_fd < 0)
-		exit(KSFT_SKIP);
+	vm->kvm_fd = open_kvm_dev_path_or_exit(perm);
 
 	if (!kvm_check_cap(KVM_CAP_IMMEDIATE_EXIT)) {
 		print_skip("immediate_exit not available");
@@ -925,9 +941,7 @@ static int vcpu_mmap_sz(void)
 {
 	int dev_fd, ret;
 
-	dev_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (dev_fd < 0)
-		exit(KSFT_SKIP);
+	dev_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	ret = ioctl(dev_fd, KVM_GET_VCPU_MMAP_SIZE, NULL);
 	TEST_ASSERT(ret >= sizeof(struct kvm_run),
@@ -2015,10 +2029,7 @@ bool vm_is_unrestricted_guest(struct kvm_vm *vm)
 
 	if (vm == NULL) {
 		/* Ensure that the KVM vendor-specific module is loaded. */
-		f = fopen(KVM_DEV_PATH, "r");
-		TEST_ASSERT(f != NULL, "Error in opening KVM dev file: %d",
-			    errno);
-		fclose(f);
+		close(open_kvm_dev_path_or_exit(O_RDONLY));
 	}
 
 	f = fopen("/sys/module/kvm_intel/parameters/unrestricted_guest", "r");
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index a8906e60a108..1ce0a37d8a89 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -657,9 +657,7 @@ struct kvm_cpuid2 *kvm_get_supported_cpuid(void)
 		return cpuid;
 
 	cpuid = allocate_kvm_cpuid2();
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	ret = ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, cpuid);
 	TEST_ASSERT(ret == 0, "KVM_GET_SUPPORTED_CPUID failed %d %d\n",
@@ -691,9 +689,7 @@ uint64_t kvm_get_feature_msr(uint64_t msr_index)
 
 	buffer.header.nmsrs = 1;
 	buffer.entry.index = msr_index;
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	r = ioctl(kvm_fd, KVM_GET_MSRS, &buffer.header);
 	TEST_ASSERT(r == 1, "KVM_GET_MSRS IOCTL failed,\n"
@@ -986,9 +982,7 @@ struct kvm_msr_list *kvm_get_msr_index_list(void)
 	struct kvm_msr_list *list;
 	int nmsrs, r, kvm_fd;
 
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	nmsrs = kvm_get_num_msrs_fd(kvm_fd);
 	list = malloc(sizeof(*list) + nmsrs * sizeof(list->indices[0]));
@@ -1312,9 +1306,7 @@ struct kvm_cpuid2 *kvm_get_supported_hv_cpuid(void)
 		return cpuid;
 
 	cpuid = allocate_kvm_cpuid2();
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	ret = ioctl(kvm_fd, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
 	TEST_ASSERT(ret == 0, "KVM_GET_SUPPORTED_HV_CPUID failed %d %d\n",
diff --git a/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c b/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
index cb953df4d7d0..91373935bff6 100644
--- a/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
+++ b/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
@@ -37,9 +37,7 @@ static void test_get_msr_index(void)
 	int old_res, res, kvm_fd, r;
 	struct kvm_msr_list *list;
 
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	old_res = kvm_num_index_msrs(kvm_fd, 0);
 	TEST_ASSERT(old_res != 0, "Expecting nmsrs to be > 0");
@@ -101,9 +99,7 @@ static void test_get_msr_feature(void)
 	int res, old_res, i, kvm_fd;
 	struct kvm_msr_list *feature_list;
 
-	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
-	if (kvm_fd < 0)
-		exit(KSFT_SKIP);
+	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
 
 	old_res = kvm_num_feature_msrs(kvm_fd, 0);
 	TEST_ASSERT(old_res != 0, "Expecting nmsrs to be > 0");
-- 
2.31.1.607.g51e8a6a459-goog


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v2] KVM: selftests: Print a message if /dev/kvm is missing
  2021-05-08  0:28 [PATCH v2] KVM: selftests: Print a message if /dev/kvm is missing David Matlack
@ 2021-05-10  6:28 ` Andrew Jones
  0 siblings, 0 replies; 2+ messages in thread
From: Andrew Jones @ 2021-05-10  6:28 UTC (permalink / raw)
  To: David Matlack; +Cc: kvm, Paolo Bonzini, Aaron Lewis

On Sat, May 08, 2021 at 12:28:32AM +0000, David Matlack wrote:
> If a KVM selftest is run on a machine without /dev/kvm, it will exit
> silently. Make it easy to tell what's happening by printing an error
> message.
> 
> Opportunistically consolidate all codepaths that open /dev/kvm into a
> single function so they all print the same message.
> 
> This slightly changes the semantics of vm_is_unrestricted_guest() by
> changing a TEST_ASSERT() to exit(KSFT_SKIP). However
> vm_is_unrestricted_guest() is only called in one place
> (x86_64/mmio_warning_test.c) and that is to determine if the test should
> be skipped or not.
> 
> Signed-off-by: David Matlack <dmatlack@google.com>
> ---
>  .../testing/selftests/kvm/include/kvm_util.h  |  1 +
>  tools/testing/selftests/kvm/lib/kvm_util.c    | 39 ++++++++++++-------
>  .../selftests/kvm/lib/x86_64/processor.c      | 16 ++------
>  .../kvm/x86_64/get_msr_index_features.c       |  8 +---
>  4 files changed, 32 insertions(+), 32 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index a8f022794ce3..401393a8c2b7 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -77,6 +77,7 @@ struct vm_guest_mode_params {
>  };
>  extern const struct vm_guest_mode_params vm_guest_mode_params[];
>  
> +int open_kvm_dev_path_or_exit(int flags);
>  int kvm_check_cap(long cap);
>  int vm_enable_cap(struct kvm_vm *vm, struct kvm_enable_cap *cap);
>  int vcpu_enable_cap(struct kvm_vm *vm, uint32_t vcpu_id,
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index fc83f6c5902d..10d488f83e3a 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -31,6 +31,27 @@ static void *align(void *x, size_t size)
>  	return (void *) (((size_t) x + mask) & ~mask);
>  }
>  
> +/* Open KVM_DEV_PATH if available, otherwise exit the entire program.

nit: We use the style where '/*' is on its own line.

> + *
> + * Input Args:
> + *   flags - The flags to pass when opening KVM_DEV_PATH.
> + *
> + * Return:
> + *   The opened file descriptor of /dev/kvm.
> + */
> +int open_kvm_dev_path_or_exit(int flags)
> +{
> +	int fd;
> +
> +	fd = open(KVM_DEV_PATH, flags);
> +	if (fd < 0) {
> +		print_skip("%s not available", KVM_DEV_PATH);
> +		exit(KSFT_SKIP);
> +	}
> +
> +	return fd;
> +}
> +
>  /*
>   * Capability
>   *
> @@ -52,10 +73,7 @@ int kvm_check_cap(long cap)
>  	int ret;
>  	int kvm_fd;
>  
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> -
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  	ret = ioctl(kvm_fd, KVM_CHECK_EXTENSION, cap);
>  	TEST_ASSERT(ret != -1, "KVM_CHECK_EXTENSION IOCTL failed,\n"
>  		"  rc: %i errno: %i", ret, errno);
> @@ -128,9 +146,7 @@ void vm_enable_dirty_ring(struct kvm_vm *vm, uint32_t ring_size)
>  
>  static void vm_open(struct kvm_vm *vm, int perm)
>  {
> -	vm->kvm_fd = open(KVM_DEV_PATH, perm);
> -	if (vm->kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	vm->kvm_fd = open_kvm_dev_path_or_exit(perm);
>  
>  	if (!kvm_check_cap(KVM_CAP_IMMEDIATE_EXIT)) {
>  		print_skip("immediate_exit not available");
> @@ -925,9 +941,7 @@ static int vcpu_mmap_sz(void)
>  {
>  	int dev_fd, ret;
>  
> -	dev_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (dev_fd < 0)
> -		exit(KSFT_SKIP);
> +	dev_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	ret = ioctl(dev_fd, KVM_GET_VCPU_MMAP_SIZE, NULL);
>  	TEST_ASSERT(ret >= sizeof(struct kvm_run),
> @@ -2015,10 +2029,7 @@ bool vm_is_unrestricted_guest(struct kvm_vm *vm)
>  
>  	if (vm == NULL) {
>  		/* Ensure that the KVM vendor-specific module is loaded. */
> -		f = fopen(KVM_DEV_PATH, "r");
> -		TEST_ASSERT(f != NULL, "Error in opening KVM dev file: %d",
> -			    errno);
> -		fclose(f);
> +		close(open_kvm_dev_path_or_exit(O_RDONLY));
>  	}
>  
>  	f = fopen("/sys/module/kvm_intel/parameters/unrestricted_guest", "r");
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index a8906e60a108..1ce0a37d8a89 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -657,9 +657,7 @@ struct kvm_cpuid2 *kvm_get_supported_cpuid(void)
>  		return cpuid;
>  
>  	cpuid = allocate_kvm_cpuid2();
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	ret = ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, cpuid);
>  	TEST_ASSERT(ret == 0, "KVM_GET_SUPPORTED_CPUID failed %d %d\n",
> @@ -691,9 +689,7 @@ uint64_t kvm_get_feature_msr(uint64_t msr_index)
>  
>  	buffer.header.nmsrs = 1;
>  	buffer.entry.index = msr_index;
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	r = ioctl(kvm_fd, KVM_GET_MSRS, &buffer.header);
>  	TEST_ASSERT(r == 1, "KVM_GET_MSRS IOCTL failed,\n"
> @@ -986,9 +982,7 @@ struct kvm_msr_list *kvm_get_msr_index_list(void)
>  	struct kvm_msr_list *list;
>  	int nmsrs, r, kvm_fd;
>  
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	nmsrs = kvm_get_num_msrs_fd(kvm_fd);
>  	list = malloc(sizeof(*list) + nmsrs * sizeof(list->indices[0]));
> @@ -1312,9 +1306,7 @@ struct kvm_cpuid2 *kvm_get_supported_hv_cpuid(void)
>  		return cpuid;
>  
>  	cpuid = allocate_kvm_cpuid2();
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	ret = ioctl(kvm_fd, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
>  	TEST_ASSERT(ret == 0, "KVM_GET_SUPPORTED_HV_CPUID failed %d %d\n",
> diff --git a/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c b/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
> index cb953df4d7d0..91373935bff6 100644
> --- a/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
> +++ b/tools/testing/selftests/kvm/x86_64/get_msr_index_features.c
> @@ -37,9 +37,7 @@ static void test_get_msr_index(void)
>  	int old_res, res, kvm_fd, r;
>  	struct kvm_msr_list *list;
>  
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	old_res = kvm_num_index_msrs(kvm_fd, 0);
>  	TEST_ASSERT(old_res != 0, "Expecting nmsrs to be > 0");
> @@ -101,9 +99,7 @@ static void test_get_msr_feature(void)
>  	int res, old_res, i, kvm_fd;
>  	struct kvm_msr_list *feature_list;
>  
> -	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
> -	if (kvm_fd < 0)
> -		exit(KSFT_SKIP);
> +	kvm_fd = open_kvm_dev_path_or_exit(O_RDONLY);
>  
>  	old_res = kvm_num_feature_msrs(kvm_fd, 0);
>  	TEST_ASSERT(old_res != 0, "Expecting nmsrs to be > 0");
> -- 
> 2.31.1.607.g51e8a6a459-goog
>

Reviewed-by: Andrew Jones <drjones@redhat.com>

Thanks,
drew


^ permalink raw reply	[flat|nested] 2+ messages in thread

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