[PATCH v6 40/51] x86/pvclock: WARN if pvclock's valid_flags are overwritten

WARN if the common PV clock valid_flags are overwritten; all PV clocks
expect that they are the one and only PV clock, i.e. don't guard against
another PV clock having modified the flags.

Reviewed-by: David Woodhouse <redacted>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kernel/pvclock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index a51adce67f92..8d098841a225 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c

@@ -21,6 +21,7 @@ static struct pvclock_vsyscall_time_info *pvti_cpu0_va __ro_after_init;
 
 void __init pvclock_set_flags(u8 flags)
 {
+	WARN_ON(valid_flags);
 	valid_flags = flags;
 }
 

-- 
2.55.0.679.g6767b8d81c-goog