2024-05-23 11:38:21

by Colin Ian King

Subject: [PATCH][next] selftests: kvm: fix shift of 32 bit unsigned int more than 32 bits

Currrentl a 32 bit 1u value is being shifted more than 32 bits causing
overflow and incorrect checking of bits 32-63. Fix this by using the
BIT_ULL macro for shifting bits.

Detected by cppcheck:
sev_init2_tests.c:108:34: error: Shifting 32-bit value by 63 bits is
undefined behaviour [shiftTooManyBits]

Fixes: dfc083a181ba ("selftests: kvm: add tests for KVM_SEV_INIT2")
Signed-off-by: Colin Ian King <[email protected]>
---
tools/testing/selftests/kvm/x86_64/sev_init2_tests.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c b/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
index 7a4a61be119b..ea09f7a06aa4 100644
--- a/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
@@ -105,11 +105,11 @@ void test_features(uint32_t vm_type, uint64_t supported_features)
int i;

for (i = 0; i < 64; i++) {
- if (!(supported_features & (1u << i)))
+ if (!(supported_features & BIT_ULL(i)))
test_init2_invalid(vm_type,
&(struct kvm_sev_init){ .vmsa_features = BIT_ULL(i) },
"unknown feature");
- else if (KNOWN_FEATURES & (1u << i))
+ else if (KNOWN_FEATURES & BIT_ULL(u))
test_init2(vm_type,
&(struct kvm_sev_init){ .vmsa_features = BIT_ULL(i) });
}
--
2.39.2

2024-05-23 15:35:22

by Dan Carpenter

Subject: Re: [PATCH][next] selftests: kvm: fix shift of 32 bit unsigned int more than 32 bits

On Thu, May 23, 2024 at 12:38:02PM +0100, Colin Ian King wrote:
> Currrentl a 32 bit 1u value is being shifted more than 32 bits causing
> overflow and incorrect checking of bits 32-63. Fix this by using the
> BIT_ULL macro for shifting bits.
>
> Detected by cppcheck:
> sev_init2_tests.c:108:34: error: Shifting 32-bit value by 63 bits is
> undefined behaviour [shiftTooManyBits]
>
> Fixes: dfc083a181ba ("selftests: kvm: add tests for KVM_SEV_INIT2")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> tools/testing/selftests/kvm/x86_64/sev_init2_tests.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c b/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
> index 7a4a61be119b..ea09f7a06aa4 100644
> --- a/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
> +++ b/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
> @@ -105,11 +105,11 @@ void test_features(uint32_t vm_type, uint64_t supported_features)
> int i;
>
> for (i = 0; i < 64; i++) {
> - if (!(supported_features & (1u << i)))
> + if (!(supported_features & BIT_ULL(i)))
> test_init2_invalid(vm_type,
> &(struct kvm_sev_init){ .vmsa_features = BIT_ULL(i) },
> "unknown feature");
> - else if (KNOWN_FEATURES & (1u << i))
> + else if (KNOWN_FEATURES & BIT_ULL(u))
^
Should be i. How does this build? :P

regards,
dan carpenter

2024-05-23 15:38:12

by Colin Ian King

Subject: Re: [PATCH][next] selftests: kvm: fix shift of 32 bit unsigned int more than 32 bits

On 23/05/2024 16:35, Dan Carpenter wrote:
> On Thu, May 23, 2024 at 12:38:02PM +0100, Colin Ian King wrote:
>> Currrentl a 32 bit 1u value is being shifted more than 32 bits causing
>> overflow and incorrect checking of bits 32-63. Fix this by using the
>> BIT_ULL macro for shifting bits.
>>
>> Detected by cppcheck:
>> sev_init2_tests.c:108:34: error: Shifting 32-bit value by 63 bits is
>> undefined behaviour [shiftTooManyBits]
>>
>> Fixes: dfc083a181ba ("selftests: kvm: add tests for KVM_SEV_INIT2")
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> tools/testing/selftests/kvm/x86_64/sev_init2_tests.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c b/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
>> index 7a4a61be119b..ea09f7a06aa4 100644
>> --- a/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
>> +++ b/tools/testing/selftests/kvm/x86_64/sev_init2_tests.c
>> @@ -105,11 +105,11 @@ void test_features(uint32_t vm_type, uint64_t supported_features)
>> int i;
>>
>> for (i = 0; i < 64; i++) {
>> - if (!(supported_features & (1u << i)))
>> + if (!(supported_features & BIT_ULL(i)))
>> test_init2_invalid(vm_type,
>> &(struct kvm_sev_init){ .vmsa_features = BIT_ULL(i) },
>> "unknown feature");
>> - else if (KNOWN_FEATURES & (1u << i))
>> + else if (KNOWN_FEATURES & BIT_ULL(u))
> ^
> Should be i. How does this build? :P

good catch, I sent the wrong one :-(
>
> regards,
> dan carpenter
>