From: Babu Moger <Babu.Moger@xxxxxxx>
The test ./x86/access fails with a timeout. This is due to the number test
combination. The test cases increase exponentially as the features get
enabled. The new machine adds the feature AC_CPU_CR4_PKE. The default
timeout is 180 seconds. Seen this problem both on AMD and Intel machines.
Test fails with following messages.
#./tests/access
qemu-system-x86_64: terminating on signal 15 from pid 20050 (timeout)
FAIL access (timeout; duration=180)
This test can take about 7 minutes without timeout.
time ./tests/access
58982405 tests, 0 failures
PASS access
real 7m10.063s
user 7m9.063s
sys 0m0.309s
Fix the problem by adding a new check to limit to the number of tests. The
new a check limits the combinations with more than one reserved bits. With
this limit, the runtime goes down from 7 minutes to approximately 2 minutes.
Signed-off-by: Babu Moger <Babu.Moger@xxxxxxx>
---
x86/access.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/x86/access.c b/x86/access.c
index 47807cc..c71f39d 100644
--- a/x86/access.c
+++ b/x86/access.c
@@ -315,11 +315,14 @@ static _Bool ac_test_legal(ac_test_t *at)
return false;
/*
- * Shorten the test by avoiding testing too many reserved bit combinations
+ * Shorten the test by avoiding testing too many reserved bit combinations.
+ * Skip testing multiple reserved bits to shorten the test. Reserved bit
+ * page faults are terminal and multiple reserved bits do not affect the
+ * error code; the odds of a KVM bug are super low, and the odds of actually
+ * being able to detect a bug are even lower.
*/
- if ((F(AC_PDE_BIT51) + F(AC_PDE_BIT36) + F(AC_PDE_BIT13)) > 1)
- return false;
- if ((F(AC_PTE_BIT51) + F(AC_PTE_BIT36)) > 1)
+ if ((F(AC_PDE_BIT51) + F(AC_PDE_BIT36) + F(AC_PDE_BIT13) +
+ F(AC_PTE_BIT51) + F(AC_PTE_BIT36)) > 1)
return false;
return true;
