Merge tag 'char-misc-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregk...

[karo-tx-linux.git] / arch / powerpc / mm / tlb-radix.c

diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index 744e0164ecf58551f036ef30e19a79638adcaa76..16ae1bbe13f09e588919f8aa55a81ed575290360 100644 (file)
--- a/arch/powerpc/mm/tlb-radix.c
+++ b/arch/powerpc/mm/tlb-radix.c
@@ -12,12 +12,12 @@
 #include <linux/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/memblock.h>
-#include <asm/ppc-opcode.h>
 
+#include <asm/ppc-opcode.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
 #include <asm/trace.h>
-
+#include <asm/cputhreads.h>
 
 #define RIC_FLUSH_TLB 0
 #define RIC_FLUSH_PWC 1
@@ -454,3 +454,44 @@ void radix__flush_tlb_pte_p9_dd1(unsigned long old_pte, struct mm_struct *mm,
        else
                radix__flush_tlb_page_psize(mm, address, mmu_virtual_psize);
 }
+
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+extern void radix_kvm_prefetch_workaround(struct mm_struct *mm)
+{
+       unsigned int pid = mm->context.id;
+
+       if (unlikely(pid == MMU_NO_CONTEXT))
+               return;
+
+       /*
+        * If this context hasn't run on that CPU before and KVM is
+        * around, there's a slim chance that the guest on another
+        * CPU just brought in obsolete translation into the TLB of
+        * this CPU due to a bad prefetch using the guest PID on
+        * the way into the hypervisor.
+        *
+        * We work around this here. If KVM is possible, we check if
+        * any sibling thread is in KVM. If it is, the window may exist
+        * and thus we flush that PID from the core.
+        *
+        * A potential future improvement would be to mark which PIDs
+        * have never been used on the system and avoid it if the PID
+        * is new and the process has no other cpumask bit set.
+        */
+       if (cpu_has_feature(CPU_FTR_HVMODE) && radix_enabled()) {
+               int cpu = smp_processor_id();
+               int sib = cpu_first_thread_sibling(cpu);
+               bool flush = false;
+
+               for (; sib <= cpu_last_thread_sibling(cpu) && !flush; sib++) {
+                       if (sib == cpu)
+                               continue;
+                       if (paca[sib].kvm_hstate.kvm_vcpu)
+                               flush = true;
+               }
+               if (flush)
+                       _tlbiel_pid(pid, RIC_FLUSH_ALL);
+       }
+}
+EXPORT_SYMBOL_GPL(radix_kvm_prefetch_workaround);
+#endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */