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-rw-r--r--arch/powerpc/mm/tlb-radix.c45
1 files changed, 43 insertions, 2 deletions
diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index 744e0164ecf5..16ae1bbe13f0 100644
--- 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 */