[PATCH v2] KVM: x86/cpuid: add type suffix to decimal const 48 fix building warning

[PATCH v2] KVM: x86/cpuid: add type suffix to decimal const 48 fix building warning

[Ethan Zhao]

The default type of a decimal constant is determined by the magnitude of
its value. If the value falls within the range of int, its type is int;
otherwise, if it falls within the range of unsigned int, its type is
unsigned int. This results in the constant 48 being of type int. In the
following min call,

g_phys_as = min(g_phys_as, 48);

This leads to a building warning/error (CONFIG_KVM_WERROR=y) caused by
the mismatch between the types of the two arguments to macro min. By
adding the suffix U to explicitly declare the type of the constant, this
issue is fixed.

Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
---
v2: fix typo in subject.
---
 arch/x86/kvm/cpuid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 2cbb3874ad39..aa2c319118bc 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1704,7 +1704,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			phys_as = entry->eax & 0xff;
 			g_phys_as = phys_as;
 			if (kvm_mmu_get_max_tdp_level() < 5)
-				g_phys_as = min(g_phys_as, 48);
+				g_phys_as = min(g_phys_as, 48U);
 		}
 
 		entry->eax = phys_as | (virt_as << 8) | (g_phys_as << 16);
-- 
2.31.1

Re: [PATCH v2] KVM: x86/cpuid: add type suffix to decimal const 48 fix building warning

[Sean Christopherson]

On Mon, 27 Jan 2025 09:38:37 +0800, Ethan Zhao wrote:
> The default type of a decimal constant is determined by the magnitude of
> its value. If the value falls within the range of int, its type is int;
> otherwise, if it falls within the range of unsigned int, its type is
> unsigned int. This results in the constant 48 being of type int. In the
> following min call,
> 
> g_phys_as = min(g_phys_as, 48);
> 
> [...]

Applied to kvm-x86 misc, thanks!

[1/1] KVM: x86/cpuid: add type suffix to decimal const 48 fix building warning
      https://github.com/kvm-x86/linux/commit/a11128ce1636

--
https://github.com/kvm-x86/linux/tree/next