Merge tag 'iwlwifi-next-for-kalle-2014-12-30' of https://git.kernel.org/pub/scm/linux...

[cascardo/linux.git] / arch / powerpc / kvm / book3s_hv_rm_xics.c

diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
index 3ee38e6..7b066f6 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rm_xics.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -183,8 +183,10 @@ static void icp_rm_down_cppr(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
         * state update in HW (ie bus transactions) so we can handle them
         * separately here as well.
         */
-       if (resend)
+       if (resend) {
                icp->rm_action |= XICS_RM_CHECK_RESEND;
+               icp->rm_resend_icp = icp;
+       }
 }
 
 
@@ -254,10 +256,25 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
         * nothing needs to be done as there can be no XISR to
         * reject.
         *
+        * ICP state: Check_IPI
+        *
         * If the CPPR is less favored, then we might be replacing
-        * an interrupt, and thus need to possibly reject it as in
+        * an interrupt, and thus need to possibly reject it.
         *
-        * ICP state: Check_IPI
+        * ICP State: IPI
+        *
+        * Besides rejecting any pending interrupts, we also
+        * update XISR and pending_pri to mark IPI as pending.
+        *
+        * PAPR does not describe this state, but if the MFRR is being
+        * made less favored than its earlier value, there might be
+        * a previously-rejected interrupt needing to be resent.
+        * Ideally, we would want to resend only if
+        *      prio(pending_interrupt) < mfrr &&
+        *      prio(pending_interrupt) < cppr
+        * where pending interrupt is the one that was rejected. But
+        * we don't have that state, so we simply trigger a resend
+        * whenever the MFRR is made less favored.
         */
        do {
                old_state = new_state = ACCESS_ONCE(icp->state);
@@ -270,13 +287,14 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
                resend = false;
                if (mfrr < new_state.cppr) {
                        /* Reject a pending interrupt if not an IPI */
-                       if (mfrr <= new_state.pending_pri)
+                       if (mfrr <= new_state.pending_pri) {
                                reject = new_state.xisr;
-                       new_state.pending_pri = mfrr;
-                       new_state.xisr = XICS_IPI;
+                               new_state.pending_pri = mfrr;
+                               new_state.xisr = XICS_IPI;
+                       }
                }
 
-               if (mfrr > old_state.mfrr && mfrr > new_state.cppr) {
+               if (mfrr > old_state.mfrr) {
                        resend = new_state.need_resend;
                        new_state.need_resend = 0;
                }
@@ -289,8 +307,10 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
        }
 
        /* Pass resends to virtual mode */
-       if (resend)
+       if (resend) {
                this_icp->rm_action |= XICS_RM_CHECK_RESEND;
+               this_icp->rm_resend_icp = icp;
+       }
 
        return check_too_hard(xics, this_icp);
 }