KVM: s390: irq routing for adapter interrupts.

Introduce a new interrupt class for s390 adapter interrupts and enable
irqfds for s390.

This is depending on a new s390 specific vm capability, KVM_CAP_S390_IRQCHIP,
that needs to be enabled by userspace.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

9 files changed, 209 insertions, 5 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index faf6fe9772c7..2cb1640a90ad 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -586,8 +586,8 @@ struct kvm_fpu {
 
 4.24 KVM_CREATE_IRQCHIP
 
-Capability: KVM_CAP_IRQCHIP
-Architectures: x86, ia64, ARM, arm64
+Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390)
+Architectures: x86, ia64, ARM, arm64, s390
 Type: vm ioctl
 Parameters: none
 Returns: 0 on success, -1 on error
@@ -596,7 +596,10 @@ Creates an interrupt controller model in the kernel.  On x86, creates a virtual
 ioapic, a virtual PIC (two PICs, nested), and sets up future vcpus to have a
 local APIC.  IRQ routing for GSIs 0-15 is set to both PIC and IOAPIC; GSI 16-23
 only go to the IOAPIC.  On ia64, a IOSAPIC is created. On ARM/arm64, a GIC is
-created.
+created. On s390, a dummy irq routing table is created.
+
+Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled
+before KVM_CREATE_IRQCHIP can be used.
 
 
 4.25 KVM_IRQ_LINE
@@ -1336,7 +1339,7 @@ KVM_ASSIGN_DEV_IRQ. Partial deassignment of host or guest IRQ is allowed.
 4.52 KVM_SET_GSI_ROUTING
 
 Capability: KVM_CAP_IRQ_ROUTING
-Architectures: x86 ia64
+Architectures: x86 ia64 s390
 Type: vm ioctl
 Parameters: struct kvm_irq_routing (in)
 Returns: 0 on success, -1 on error
@@ -1359,6 +1362,7 @@ struct kvm_irq_routing_entry {
         union {
                 struct kvm_irq_routing_irqchip irqchip;
                 struct kvm_irq_routing_msi msi;
+                struct kvm_irq_routing_s390_adapter adapter;
                 __u32 pad[8];
         } u;
 };
@@ -1366,6 +1370,7 @@ struct kvm_irq_routing_entry {
 /* gsi routing entry types */
 #define KVM_IRQ_ROUTING_IRQCHIP 1
 #define KVM_IRQ_ROUTING_MSI 2
+#define KVM_IRQ_ROUTING_S390_ADAPTER 3
 
 No flags are specified so far, the corresponding field must be set to zero.
 
@@ -1381,6 +1386,14 @@ struct kvm_irq_routing_msi {
         __u32 pad;
 };
 
+struct kvm_irq_routing_s390_adapter {
+        __u64 ind_addr;
+        __u64 summary_addr;
+        __u64 ind_offset;
+        __u32 summary_offset;
+        __u32 adapter_id;
+};
+
 
 4.53 KVM_ASSIGN_SET_MSIX_NR
 
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 0d5235262707..dd3933754d23 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -24,6 +24,14 @@
 #define KVM_MAX_VCPUS 64
 #define KVM_USER_MEM_SLOTS 32
 
+/*
+ * These seem to be used for allocating ->chip in the routing table,
+ * which we don't use. 4096 is an out-of-thin-air value. If we need
+ * to look at ->chip later on, we'll need to revisit this.
+ */
+#define KVM_NR_IRQCHIPS 1
+#define KVM_IRQCHIP_NUM_PINS 4096
+
 struct sca_entry {
         atomic_t scn;
         __u32   reserved;
@@ -274,6 +282,7 @@ struct kvm_arch{
         struct kvm_device *flic;
         struct gmap *gmap;
         int css_support;
+        int use_irqchip;
         struct s390_io_adapter *adapters[MAX_S390_IO_ADAPTERS];
 };
 
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index c8bacbcd2e5b..10d529ac9821 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -25,6 +25,8 @@ config KVM
         select HAVE_KVM_EVENTFD
         select KVM_ASYNC_PF
         select KVM_ASYNC_PF_SYNC
+        select HAVE_KVM_IRQCHIP
+        select HAVE_KVM_IRQ_ROUTING
         ---help---
           Support hosting paravirtualized guest machines using the SIE
           virtualization capability on the mainframe. This should work
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index a47d2c355f68..d3adb37e93a4 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -7,7 +7,7 @@
 # as published by the Free Software Foundation.
 
 KVM := ../../../virt/kvm
-common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o  $(KVM)/async_pf.o
+common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o  $(KVM)/async_pf.o $(KVM)/irqchip.o
 
 ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
 
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 7ecef5a18e25..2e2814eceb85 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -13,6 +13,7 @@
 #include <linux/interrupt.h>
 #include <linux/kvm_host.h>
 #include <linux/hrtimer.h>
+#include <linux/mmu_context.h>
 #include <linux/signal.h>
 #include <linux/slab.h>
 #include <asm/asm-offsets.h>
@@ -1284,3 +1285,123 @@ struct kvm_device_ops kvm_flic_ops = {
         .create = flic_create,
         .destroy = flic_destroy,
 };
+
+static unsigned long get_ind_bit(__u64 addr, unsigned long bit_nr, bool swap)
+{
+        unsigned long bit;
+
+        bit = bit_nr + (addr % PAGE_SIZE) * 8;
+
+        return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit;
+}
+
+static struct s390_map_info *get_map_info(struct s390_io_adapter *adapter,
+                                          u64 addr)
+{
+        struct s390_map_info *map;
+
+        if (!adapter)
+                return NULL;
+
+        list_for_each_entry(map, &adapter->maps, list) {
+                if (map->guest_addr == addr)
+                        return map;
+        }
+        return NULL;
+}
+
+static int adapter_indicators_set(struct kvm *kvm,
+                                  struct s390_io_adapter *adapter,
+                                  struct kvm_s390_adapter_int *adapter_int)
+{
+        unsigned long bit;