As s390 doesn't use memory writes for virtio notifcations, create
a special kind of ioeventfd instead that hooks up into diagnose
0x500 (kvm hypercall) with function code 3 (virtio-ccw notification).
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 23 ++++++
arch/s390/kvm/Kconfig | 1 +
arch/s390/kvm/Makefile | 2 +-
arch/s390/kvm/diag.c | 23 ++++++
arch/s390/kvm/kvm-s390.c | 165 +++++++++++++++++++++++++++++++++++++++
arch/s390/kvm/kvm-s390.h | 3 +
6 files changed, 216 insertions(+), 1 deletion(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 16bd5d1..8dad9dc 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -18,6 +18,7 @@
#include <linux/kvm_host.h>
#include <asm/debug.h>
#include <asm/cpu.h>
+#include <asm/schid.h>
#define KVM_MAX_VCPUS 64
#define KVM_USER_MEM_SLOTS 32
@@ -262,8 +263,30 @@ struct kvm_arch{
debug_info_t *dbf;
struct kvm_s390_float_interrupt float_int;
struct gmap *gmap;
+ struct list_head sch_fds;
+ struct rw_semaphore sch_fds_sem;
int css_support;
};
extern int sie64a(struct kvm_s390_sie_block *, u64 *);
+#define __KVM_HAVE_ARCH_IOEVENTFD
+
+#define KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY 1
+
+struct kvm_s390_ioeventfd_data {
+ __u8 type;
+ union {
+ /* VIRTIO_CCW_NOTIFY */
+ struct {
+ __u64 vq;
+ struct subchannel_id schid;
+ } virtio_ccw_vq;
+ char padding[35];
+ };
+} __packed;
+
+struct kvm_arch_ioeventfd {
+ struct list_head entry;
+ struct kvm_s390_ioeventfd_data data;
+};
#endif
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 2441ffd..dbd8cc9 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..51ea66f 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -104,6 +104,27 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
return -EREMOTE;
}
+static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
+{
+ struct kvm_s390_ioeventfd_data data;
+ u32 tmp;
+
+ /* No channel I/O? Get out quickly. */
+ if (!vcpu->kvm->arch.css_support ||
+ (vcpu->run->s.regs.gprs[1] != 3))
+ return -EOPNOTSUPP;
+
+ /* subchannel id is in gpr 2, queue in gpr 3 */
+ tmp = vcpu->run->s.regs.gprs[2] & 0xffffffff;
+ memcpy(&data.virtio_ccw_vq.schid, &tmp,
+ sizeof(data.virtio_ccw_vq.schid));
+ data.virtio_ccw_vq.vq = vcpu->run->s.regs.gprs[3];
+ data.type = KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY;
+
+ /* If signalling via eventfd fails, we want to drop to userspace. */
+ return kvm_s390_ioeventfd_signal(vcpu->kvm, &data) ? -EOPNOTSUPP : 0;
+}
+
int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
{
int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16;
@@ -118,6 +139,8 @@ 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 58a5f03..cd9eb0e 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -15,6 +15,7 @@
#include <linux/compiler.h>
#include <linux/err.h>
+#include <linux/eventfd.h>
#include <linux/fs.h>
#include <linux/hrtimer.h>
#include <linux/init.h>
@@ -143,6 +144,7 @@ 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:
@@ -237,6 +239,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
if (!kvm->arch.gmap)
goto out_nogmap;
}
+ INIT_LIST_HEAD(&kvm->arch.sch_fds);
+ init_rwsem(&kvm->arch.sch_fds_sem);
kvm->arch.css_support = 0;
@@ -1028,3 +1032,164 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot)
{
}
+static void kvm_s390_ioeventfd_add(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch)
+{
+ switch (arch->data.type) {
+ case KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY:
+ down_write(&kvm->arch.sch_fds_sem);
+ list_add_tail(&arch->entry, &kvm->arch.sch_fds);
+ up_write(&kvm->arch.sch_fds_sem);
+ break;
+ default:
+ pr_warn("Trying to add ioeventfd type %x\n", arch->data.type);
+ }
+}
+
+static void kvm_s390_ioeventfd_remove(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch)
+{
+ switch (arch->data.type) {
+ case KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY:
+ down_write(&kvm->arch.sch_fds_sem);
+ list_del(&arch->entry);
+ up_write(&kvm->arch.sch_fds_sem);
+ break;
+ default:
+ pr_warn("Trying to remove ioeventfd type %x\n",
+ arch->data.type);
+ }
+}
+
+int kvm_s390_ioeventfd_signal(struct kvm *kvm,
+ struct kvm_s390_ioeventfd_data *data)
+{
+ struct kvm_arch_ioeventfd *arch, match;
+ int ret;
+
+ if (data->type != KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY)
+ return -ENOENT;
+ down_read(&kvm->arch.sch_fds_sem);
+ if (list_empty(&kvm->arch.sch_fds)) {
+ ret = -ENOENT;
+ goto out_unlock;
+ }
+ memcpy(&match.data, data, sizeof(match.data));
+ list_for_each_entry(arch, &kvm->arch.sch_fds, entry) {
+ if (!kvm_arch_ioeventfd_match(arch, &match))
+ continue;
+ ret = eventfd_signal(kvm_ioeventfd_get_eventfd(arch), 1);
+ goto out_unlock;
+ }
+ ret = -ENOENT;
+out_unlock:
+ if (ret > 0)
+ ret = 0;
+ up_read(&kvm->arch.sch_fds_sem);
+ return ret;
+}
+
+int kvm_arch_ioeventfd_check(struct kvm_ioeventfd *args)
+{
+ struct kvm_s390_ioeventfd_data *data;
+
+ if (!(args->flags & KVM_IOEVENTFD_FLAG_ARCH))
+ return -EINVAL;
+ if (args->flags & (KVM_IOEVENTFD_FLAG_DATAMATCH |
+ KVM_IOEVENTFD_FLAG_PIO))
+ return -EINVAL;
+
+ data = (struct kvm_s390_ioeventfd_data *) args->data;
+ if (data->type != KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY)
+ return -EINVAL;
+ if (((data->virtio_ccw_vq.schid.m == 1) &&
+ (data->virtio_ccw_vq.schid.cssid != 0xfe)) ||
+ ((data->virtio_ccw_vq.schid.m == 0) &&
+ (data->virtio_ccw_vq.schid.cssid != 0)))
+ return -EINVAL;
+ if (data->virtio_ccw_vq.schid.one != 1)
+ return -EINVAL;
+ if (data->virtio_ccw_vq.vq > 128)
+ return -EINVAL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_arch_ioeventfd_check);
+
+void kvm_arch_ioeventfd_init(struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args)
+{
+ INIT_LIST_HEAD(&arch->entry);
+ memcpy(&arch->data, &args->data, sizeof(arch->data));
+}
+EXPORT_SYMBOL_GPL(kvm_arch_ioeventfd_init);
+
+int kvm_arch_ioeventfd_activate(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args)
+{
+ int ret;
+
+ switch (arch->data.type) {
+ case KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY:
+ /* Fail if channel subsystem support is not active. */
+ if (!kvm->arch.css_support)
+ ret = -EINVAL;
+ else {
+ kvm_s390_ioeventfd_add(kvm, arch);
+ ret = 0;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_arch_ioeventfd_activate);
+
+bool kvm_arch_ioeventfd_match(struct kvm_arch_ioeventfd *arch,
+ struct kvm_arch_ioeventfd *to_match)
+{
+ if (arch->data.type != to_match->data.type)
+ return false;
+
+ switch (arch->data.type) {
+ case KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY:
+ if (memcmp(&arch->data.virtio_ccw_vq.schid,
+ &to_match->data.virtio_ccw_vq.schid,
+ sizeof(arch->data.virtio_ccw_vq.schid)))
+ return false;
+ if (arch->data.virtio_ccw_vq.vq !=
+ to_match->data.virtio_ccw_vq.vq)
+ return false;
+ return true;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL_GPL(kvm_arch_ioeventfd_match);
+
+bool kvm_arch_ioeventfd_match_and_release(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args)
+{
+ struct kvm_s390_ioeventfd_data *data;
+
+ data = (struct kvm_s390_ioeventfd_data *)args->data;
+ if (arch->data.type != data->type)
+ return false;
+
+ switch (arch->data.type) {
+ case KVM_S390_IOEVENTFD_VIRTIO_CCW_NOTIFY:
+ if (memcmp(&arch->data.virtio_ccw_vq.schid,
+ &data->virtio_ccw_vq.schid,
+ sizeof(arch->data.virtio_ccw_vq.schid)))
+ return false;
+ if (arch->data.virtio_ccw_vq.vq != data->virtio_ccw_vq.vq)
+ return false;
+ kvm_s390_ioeventfd_remove(kvm, arch);
+ return true;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL_GPL(kvm_arch_ioeventfd_match_and_release);
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index 4d89d64..9794906 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -136,4 +136,7 @@ int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu,
/* implemented in diag.c */
int kvm_s390_handle_diag(struct kvm_vcpu *vcpu);
+int kvm_s390_ioeventfd_signal(struct kvm *kvm,
+ struct kvm_s390_ioeventfd_data *data);
+
#endif
--
1.7.12.4
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