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, 0 insertions, 14 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 9c4294986af7..9015e5e412b5 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -824,13 +824,6 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
 
         vm_unmap_aliases();
 
-        /*
-         * If we're called with lazy mmu updates enabled, the
-         * in-memory pte state may be stale.  Flush pending updates to
-         * bring them up to date.
-         */
-        arch_flush_lazy_mmu_mode();
-
         cpa.vaddr = addr;
         cpa.numpages = numpages;
         cpa.mask_set = mask_set;
@@ -873,13 +866,6 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages,
         } else
                 cpa_flush_all(cache);
 
-        /*
-         * If we've been called with lazy mmu updates enabled, then
-         * make sure that everything gets flushed out before we
-         * return.
-         */
-        arch_flush_lazy_mmu_mode();
-
 out:
         return ret;
 }