x86/paravirt: remove lazy mode in interrupts

Impact: simplification, robustness

Make paravirt_lazy_mode() always return PARAVIRT_LAZY_NONE
when in an interrupt.  This prevents interrupt code from
accidentally inheriting an outer lazy state, and instead
does everything synchronously.  Outer batched operations
are left deferred.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a03b7279efa0..cfbb4a738011 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -225,12 +225,10 @@ static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
         if (!pmd_present(*pmd_k))
                 return NULL;
 
-        if (!pmd_present(*pmd)) {
+        if (!pmd_present(*pmd))
                 set_pmd(pmd, *pmd_k);
-                arch_flush_lazy_mmu_mode();
-        } else {
+        else
                 BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
-        }
 
         return pmd_k;
 }