KVM: PPC: Enable IRQFD support for the XICS interrupt controller

This makes it possible to use IRQFDs on platforms that use the XICS
interrupt controller.  To do this we implement kvm_irq_map_gsi() and
kvm_irq_map_chip_pin() in book3s_xics.c, so as to provide a 1-1 mapping
between global interrupt numbers and XICS interrupt source numbers.
For now, all interrupts are mapped as "IRQCHIP" interrupts, and no
MSI support is provided.

This means that kvm_set_irq can now get called with level == 0 or 1
as well as the powerpc-specific values KVM_INTERRUPT_SET,
KVM_INTERRUPT_UNSET and KVM_INTERRUPT_SET_LEVEL.  We change
ics_deliver_irq() to accept all those values, and remove its
report_status argument, as it is always false, given that we don't
support KVM_IRQ_LINE_STATUS.

This also adds support for interrupt ack notifiers to the XICS code
so that the IRQFD resampler functionality can be supported.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

4 files changed, 55 insertions, 9 deletions

diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index d4741dba91af..602eb51d20bc 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -170,6 +170,8 @@ config KVM_MPIC
 config KVM_XICS
         bool "KVM in-kernel XICS emulation"
         depends on KVM_BOOK3S_64 && !KVM_MPIC
+        select HAVE_KVM_IRQCHIP
+        select HAVE_KVM_IRQFD
         ---help---
           Include support for the XICS (eXternal Interrupt Controller
           Specification) interrupt controller architecture used on
diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
index b4b0082f761c..3ee38e6e884f 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_xics.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -401,6 +401,11 @@ int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
                 icp->rm_action |= XICS_RM_REJECT;
                 icp->rm_reject = irq;
         }
+
+        if (!hlist_empty(&vcpu->kvm->irq_ack_notifier_list)) {
+                icp->rm_action |= XICS_RM_NOTIFY_EOI;
+                icp->rm_eoied_irq = irq;
+        }
  bail:
         return check_too_hard(xics, icp);
 }
diff --git a/arch/powerpc/kvm/book3s_xics.c b/arch/powerpc/kvm/book3s_xics.c
index d1acd32a64c0..eaeb78047fb8 100644
--- a/arch/powerpc/kvm/book3s_xics.c
+++ b/arch/powerpc/kvm/book3s_xics.c
@@ -64,8 +64,12 @@
 static void icp_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
                             u32 new_irq);
 
-static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level,
-                           bool report_status)
+/*
+ * Return value ideally indicates how the interrupt was handled, but no
+ * callers look at it (given that we don't implement KVM_IRQ_LINE_STATUS),
+ * so just return 0.
+ */
+static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level)
 {
         struct ics_irq_state *state;
         struct kvmppc_ics *ics;
@@ -82,17 +86,14 @@ static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level,
         if (!state->exists)
                 return -EINVAL;
 
-        if (report_status)
-                return state->asserted;
-
         /*
          * We set state->asserted locklessly. This should be fine as
          * we are the only setter, thus concurrent access is undefined
          * to begin with.
          */
-        if (level == KVM_INTERRUPT_SET_LEVEL)
+        if (level == 1 || level == KVM_INTERRUPT_SET_LEVEL)
                 state->asserted = 1;
-        else if (level == KVM_INTERRUPT_UNSET) {
+        else if (level == 0 || level == KVM_INTERRUPT_UNSET) {
                 state->asserted = 0;
                 return 0;
         }
@@ -100,7 +101,7 @@ static int ics_deliver_irq(struct kvmppc_xics *xics, u32 irq, u32 level,
         /* Attempt delivery */
         icp_deliver_irq(xics, NULL, irq);
 
-        return state->asserted;
+        return 0;
 }
 
 static void ics_check_resend(struct kvmppc_xics *xics, struct kvmppc_ics *ics,
@@ -772,6 +773,8 @@ static noinline int kvmppc_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
         if (state->asserted)
                 icp_deliver_irq(xics, icp, irq);
 
+        kvm_notify_acked_irq(vcpu->kvm, 0, irq);
+
         return H_SUCCESS;
 }
 
@@ -789,6 +792,8 @@ static noinline int kvmppc_xics_rm_complete(struct kvm_vcpu *vcpu, u32 hcall)
                 icp_check_resend(xics, icp);
         if (icp->rm_action & XICS_RM_REJECT)
                 icp_deliver_irq(xics, icp, icp->rm_reject);
+        if (icp->rm_action & XICS_RM_NOTIFY_EOI)
+                kvm_notify_acked_irq(vcpu->kvm, 0, icp->rm_eoied_irq);
 
         icp->rm_action = 0;
 
@@ -1170,7 +1175,16 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 {
         struct kvmppc_xics *xics = kvm->arch.xics;
 
-        return ics_deliver_irq(xics, irq, level, line_status);
+        return ics_deliver_irq(xics, irq, level);
+}
+
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm *kvm,
+                int irq_source_id, int level, bool line_status)
+{
+        if (!level)
+                return -1;
+        return kvm_set_irq(kvm, irq_source_id, irq_entry->gsi,
+                           level, line_status);
 }
 
 static int xics_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
@@ -1301,3 +1315,26 @@ void kvmppc_xics_free_icp(struct kvm_vcpu *vcpu)
         vcpu->arch.icp = NULL;
         vcpu->arch.irq_type = KVMPPC_IRQ_DEFAULT;
 }
+
+static int xics_set_irq(struct kvm_kernel_irq_routing_entry *e,
+                        struct kvm *kvm, int irq_source_id, int level,
+                        bool line_status)
+{
+        return kvm_set_irq(kvm, irq_source_id, e->gsi, level, line_status);
+}
+
+int kvm_irq_map_gsi(struct kvm *kvm,
+                    struct kvm_kernel_irq_routing_entry *entries, int gsi)
+{
+        entries->gsi = gsi;
+        entries->type = KVM_IRQ_ROUTING_IRQCHIP;
+        entries->set = xics_set_irq;
+        entries->irqchip.irqchip = 0;
+        entries->irqchip.pin = gsi;
+        return 1;
+}
+
+int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+        return pin;
+}
diff --git a/arch/powerpc/kvm/book3s_xics.h b/arch/powerpc/kvm/book3s_xics.h
index dd9326c5c19b..e8aaa7a3f209 100644
--- a/arch/powerpc/kvm/book3s_xics.h
+++ b/arch/powerpc/kvm/book3s_xics.h
@@ -71,9 +71,11 @@ struct kvmppc_icp {
 #define XICS_RM_KICK_VCPU       0x1
 #define XICS_RM_CHECK_RESEND    0x2
 #define XICS_RM_REJECT          0x4
+#define XICS_RM_NOTIFY_EOI      0x8
         u32 rm_action;
         struct kvm_vcpu *rm_kick_target;
         u32  rm_reject;
+        u32  rm_eoied_irq;
 
         /* Debug stuff for real mode */
         union kvmppc_icp_state rm_dbgstate;