Shifting signed values is rarely a good idea, especially if the result
ends up setting the most significant bit. UBSAN warns about two
occasions in the CPUID filter code:
===========================
x86/cpuid.c:23:25: runtime error: left shift of 255 by 24 places cannot be represented in type 'int'
x86/cpuid.c:27:22: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
===========================
Fix those warnings by making sure we only deal with unsigned values.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
x86/cpuid.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/x86/cpuid.c b/x86/cpuid.c
index f4347a84..1ae681ce 100644
--- a/x86/cpuid.c
+++ b/x86/cpuid.c
@@ -8,7 +8,7 @@
#define MAX_KVM_CPUID_ENTRIES 100
-static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid, int cpu_id)
+static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid, unsigned int cpu_id)
{
unsigned int i;
@@ -20,11 +20,11 @@ static void filter_cpuid(struct kvm_cpuid2 *kvm_cpuid, int cpu_id)
switch (entry->function) {
case 1:
- entry->ebx &= ~(0xff << 24);
+ entry->ebx &= ~(0xffU << 24);
entry->ebx |= cpu_id << 24;
/* Set X86_FEATURE_HYPERVISOR */
if (entry->index == 0)
- entry->ecx |= (1 << 31);
+ entry->ecx |= (1U << 31);
break;
case 6:
/* Clear X86_FEATURE_EPB */
--
2.25.1
