On 30/10/2019 22.04, Bill Wendling wrote:
Shifting a negative number is undefined. Clang complains about it:
x86/svm.c:1131:38: error: shifting a negative signed value is undefined [-Werror,-Wshift-negative-value]
test->vmcb->control.tsc_offset = TSC_OFFSET_VALUE;
Using "~0ull" results in identical asm code:
before: movabsq $-281474976710656, %rsi
after: movabsq $-281474976710656, %rsi
Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx>
---
x86/svm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/x86/svm.c b/x86/svm.c
index 4ddfaa4..cef43d5 100644
--- a/x86/svm.c
+++ b/x86/svm.c
@@ -1122,7 +1122,7 @@ static bool npt_rw_l1mmio_check(struct test *test)
}
#define TSC_ADJUST_VALUE (1ll << 32)
-#define TSC_OFFSET_VALUE (-1ll << 48)
+#define TSC_OFFSET_VALUE (~0ull << 48)
static bool ok;
static void tsc_adjust_prepare(struct test *test)
Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
