10924 Need mitigation of L1TF (CVE-2018-3646)
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Peter Tribble <peter.tribble@gmail.com>

@@ -73,10 +73,11 @@
 #include <sys/schedctl.h>
 #include <sys/waitq.h>
 #include <sys/cpucaps.h>
 #include <sys/kiconv.h>
 #include <sys/ctype.h>
+#include <sys/ht.h>
 
 struct kmem_cache *thread_cache;        /* cache of free threads */
 struct kmem_cache *lwp_cache;           /* cache of free lwps */
 struct kmem_cache *turnstile_cache;     /* cache of free turnstiles */
 

@@ -485,41 +486,38 @@
         kpreempt_disable();
         curthread->t_prev->t_next = t;
         curthread->t_prev = t;
 
         /*
-         * Threads should never have a NULL t_cpu pointer so assign it
-         * here.  If the thread is being created with state TS_RUN a
-         * better CPU may be chosen when it is placed on the run queue.
-         *
-         * We need to keep kernel preemption disabled when setting all
-         * three fields to keep them in sync.  Also, always create in
-         * the default partition since that's where kernel threads go
-         * (if this isn't a kernel thread, t_cpupart will be changed
-         * in lwp_create before setting the thread runnable).
+         * We'll always create in the default partition since that's where
+         * kernel threads go (we'll change this later if needed, in
+         * lwp_create()).
          */
         t->t_cpupart = &cp_default;
 
         /*
          * For now, affiliate this thread with the root lgroup.
          * Since the kernel does not (presently) allocate its memory
          * in a locality aware fashion, the root is an appropriate home.
          * If this thread is later associated with an lwp, it will have
-         * it's lgroup re-assigned at that time.
+         * its lgroup re-assigned at that time.
          */
         lgrp_move_thread(t, &cp_default.cp_lgrploads[LGRP_ROOTID], 1);
 
         /*
-         * Inherit the current cpu.  If this cpu isn't part of the chosen
-         * lgroup, a new cpu will be chosen by cpu_choose when the thread
-         * is ready to run.
+         * If the current CPU is in the default cpupart, use it.  Otherwise,
+         * pick one that is; before entering the dispatcher code, we'll
+         * make sure to keep the invariant that ->t_cpu is set.  (In fact, we
+         * rely on this, in ht_should_run(), in the call tree of
+         * disp_lowpri_cpu().)
          */
-        if (CPU->cpu_part == &cp_default)
+        if (CPU->cpu_part == &cp_default) {
                 t->t_cpu = CPU;
-        else
-                t->t_cpu = disp_lowpri_cpu(cp_default.cp_cpulist, t->t_lpl,
-                    t->t_pri, NULL);
+        } else {
+                t->t_cpu = cp_default.cp_cpulist;
+                t->t_cpu = disp_lowpri_cpu(t->t_cpu, t, t->t_pri);
+        }
 
         t->t_disp_queue = t->t_cpu->cpu_disp;
         kpreempt_enable();
 
         /*

@@ -1324,10 +1322,12 @@
         ASSERT(t->t_intr != NULL);
 
         itp = t->t_intr;                /* interrupted thread */
         t->t_intr = NULL;               /* clear interrupt ptr */
 
+        ht_end_intr();
+
         /*
          * Get state from interrupt thread for the one
          * it interrupted.
          */