[PATCH v4 6/6] KVM: s390: Wire up ioeventfd.

Cornelia Huck
2013-02-28T09:22:32Z

Enable ioeventfd support on s390 and hook up diagnose 500 virtio-ccw
notifications.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
arch/s390/kvm/Kconfig | 1 +
arch/s390/kvm/Makefile | 2 +-
arch/s390/kvm/diag.c | 26 ++++++++++++++++++++++++++
arch/s390/kvm/kvm-s390.c | 1 +
4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index b58dd86..3c43e30 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -22,6 +22,7 @@ config KVM
select PREEMPT_NOTIFIERS
select ANON_INODES
select HAVE_KVM_CPU_RELAX_INTERCEPT
+ select HAVE_KVM_EVENTFD
---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 3975722..8fe9d65 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -6,7 +6,7 @@
# it under the terms of the GNU General Public License (version 2 only)
# as published by the Free Software Foundation.

-common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o)
+common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o eventfd.o)

ccflags-y := -Ivirt/kvm -Iarch/s390/kvm

diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index a390687..96907f2 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -13,6 +13,7 @@

#include <linux/kvm.h>
#include <linux/kvm_host.h>
+#include <asm/virtio-ccw.h>
#include "kvm-s390.h"
#include "trace.h"
#include "trace-s390.h"
@@ -104,6 +105,29 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
return -EREMOTE;
}

+static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
+{
+ int ret, idx;
+
+ /* No virtio-ccw notification? Get out quickly. */
+ if (!vcpu->kvm->arch.css_support ||
+ (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
+ return -EOPNOTSUPP;
+
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+ /*
+ * The layout is as follows:
+ * - gpr 2 contains the subchannel id (passed as addr)
+ * - gpr 3 contains the virtqueue index (passed as datamatch)
+ */
+ ret = kvm_io_bus_write(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
+ vcpu->run->s.regs.gprs[2],
+ 8, &vcpu->run->s.regs.gprs[3]);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+ /* kvm_io_bus_write returns -EOPNOTSUPP if it found no match. */
+ return ret;
+}
+
int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
{
int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;
@@ -118,6 +142,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
return __diag_time_slice_end_directed(vcpu);
case 0x308:
return __diag_ipl_functions(vcpu);
+ case 0x500:
+ return __diag_virtio_hypercall(vcpu);
default:
return -EOPNOTSUPP;
}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index f822d36..04d2454 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -142,6 +142,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_ONE_REG:
case KVM_CAP_ENABLE_CAP:
case KVM_CAP_S390_CSS_SUPPORT:
+ case KVM_CAP_IOEVENTFD:
r = 1;
break;
case KVM_CAP_NR_VCPUS:
--
1.7.12.4