[PATCH] KVM: x86/mmu: fix comparison of u8 with -1

From: Colin King
Date: Tue Nov 26 2019 - 11:21:53 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The comparison of the u8 value __entry->u with -1 is always
going to be false because a __entry-u can never be negative.
Fix this by casting it to a s8 integer.

Addresses clang warning:
arch/x86/kvm/./mmutrace.h:360:16: warning: result of comparison
of constant -1 with expression of type 'u8' (aka 'unsigned char')
is always false [-Wtautological-constant-out-of-range-compare]

Fixes: 335e192a3fa4 ("KVM: x86: add tracepoints around __direct_map and FNAME(fetch)")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmutrace.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index 7ca8831c7d1a..3466cd528a67 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -357,7 +357,7 @@ TRACE_EVENT(
__entry->r ? "r" : "-",
__entry->spte & PT_WRITABLE_MASK ? "w" : "-",
__entry->x ? "x" : "-",
- __entry->u == -1 ? "" : (__entry->u ? "u" : "-"),
+ (s8)__entry->u == -1 ? "" : (__entry->u ? "u" : "-"),
__entry->level, __entry->sptep
)
);
--
2.24.0