Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[cascardo/linux.git] / arch / powerpc / kvm / book3s_hv_rmhandlers.S

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 0a2d64f..10554df 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -190,8 +190,6 @@ kvmppc_primary_no_guest:
        bge     kvm_novcpu_exit /* another thread already exiting */
        li      r3, NAPPING_NOVCPU
        stb     r3, HSTATE_NAPPING(r13)
-       li      r3, 1
-       stb     r3, HSTATE_HWTHREAD_REQ(r13)
 
        b       kvm_do_nap
 
@@ -282,6 +280,8 @@ kvm_start_guest:
        /* if we have no vcpu to run, go back to sleep */
        beq     kvm_no_guest
 
+kvm_secondary_got_guest:
+
        /* Set HSTATE_DSCR(r13) to something sensible */
        ld      r6, PACA_DSCR(r13)
        std     r6, HSTATE_DSCR(r13)
@@ -307,27 +307,46 @@ kvm_start_guest:
        stwcx.  r3, 0, r4
        bne     51b
 
+/*
+ * At this point we have finished executing in the guest.
+ * We need to wait for hwthread_req to become zero, since
+ * we may not turn on the MMU while hwthread_req is non-zero.
+ * While waiting we also need to check if we get given a vcpu to run.
+ */
 kvm_no_guest:
-       li      r0, KVM_HWTHREAD_IN_NAP
+       lbz     r3, HSTATE_HWTHREAD_REQ(r13)
+       cmpwi   r3, 0
+       bne     53f
+       HMT_MEDIUM
+       li      r0, KVM_HWTHREAD_IN_KERNEL
        stb     r0, HSTATE_HWTHREAD_STATE(r13)
-kvm_do_nap:
-       /* Clear the runlatch bit before napping */
-       mfspr   r2, SPRN_CTRLF
-       clrrdi  r2, r2, 1
-       mtspr   SPRN_CTRLT, r2
-
+       /* need to recheck hwthread_req after a barrier, to avoid race */
+       sync
+       lbz     r3, HSTATE_HWTHREAD_REQ(r13)
+       cmpwi   r3, 0
+       bne     54f
+/*
+ * We jump to power7_wakeup_loss, which will return to the caller
+ * of power7_nap in the powernv cpu offline loop.  The value we
+ * put in r3 becomes the return value for power7_nap.
+ */
        li      r3, LPCR_PECE0
        mfspr   r4, SPRN_LPCR
        rlwimi  r4, r3, 0, LPCR_PECE0 | LPCR_PECE1
        mtspr   SPRN_LPCR, r4
-       isync
-       std     r0, HSTATE_SCRATCH0(r13)
-       ptesync
-       ld      r0, HSTATE_SCRATCH0(r13)
-1:     cmpd    r0, r0
-       bne     1b
-       nap
-       b       .
+       li      r3, 0
+       b       power7_wakeup_loss
+
+53:    HMT_LOW
+       ld      r4, HSTATE_KVM_VCPU(r13)
+       cmpdi   r4, 0
+       beq     kvm_no_guest
+       HMT_MEDIUM
+       b       kvm_secondary_got_guest
+
+54:    li      r0, KVM_HWTHREAD_IN_KVM
+       stb     r0, HSTATE_HWTHREAD_STATE(r13)
+       b       kvm_no_guest
 
 /******************************************************************************
  *                                                                            *
@@ -1939,6 +1958,7 @@ _GLOBAL(kvmppc_h_cede)
         * occurs, with PECE1, PECE0 and PECEDP set in LPCR. Also clear the
         * runlatch bit before napping.
         */
+kvm_do_nap:
        mfspr   r2, SPRN_CTRLF
        clrrdi  r2, r2, 1
        mtspr   SPRN_CTRLT, r2