Currently, ioeventfds are designed to work on architectures that
can trap I/O memory writes. This won't work for architectures like
s390, however; therefore provide a way for architectures to override
this with an architecture-specific implementation.
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
Documentation/virtual/kvm/api.txt | 5 +-
include/linux/kvm_host.h | 13 +++
include/uapi/linux/kvm.h | 4 +-
virt/kvm/eventfd.c | 181 ++++++++++++++++++++++++++------------
4 files changed, 146 insertions(+), 57 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c2534c3..13c038c 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1465,7 +1465,7 @@ struct kvm_ioeventfd {
__u32 len; /* 1, 2, 4, or 8 bytes */
__s32 fd;
__u32 flags;
- __u8 pad[36];
+ __u8 data[36]; /* for architecture-specific data */
};
The following flags are defined:
@@ -1473,10 +1473,13 @@ The following flags are defined:
#define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
#define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
#define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
+#define KVM_IOEVENTFD_FLAG_ARCH (1 << kvm_ioeventfd_flag_nr_arch)
If datamatch flag is set, the event will be signaled only if the written value
to the registered address is equal to datamatch in struct kvm_ioeventfd.
+If the arch flag is set, the eventfd will use the data field. If the arch flag
+is not set, the data field is not valid.
4.60 KVM_DIRTY_TLB
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 722cae7..d7965fb 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -905,8 +905,21 @@ static inline void kvm_free_irq_routing(struct kvm *kvm) {}
#ifdef CONFIG_HAVE_KVM_EVENTFD
+struct kvm_arch_ioeventfd;
void kvm_eventfd_init(struct kvm *kvm);
int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args);
+struct eventfd_ctx *kvm_ioeventfd_get_eventfd(struct kvm_arch_ioeventfd *arch);
+int kvm_arch_ioeventfd_check(struct kvm_ioeventfd *args);
+void kvm_arch_ioeventfd_init(struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args);
+int kvm_arch_ioeventfd_activate(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args);
+bool kvm_arch_ioeventfd_match(struct kvm_arch_ioeventfd *arch,
+ struct kvm_arch_ioeventfd *to_match);
+bool kvm_arch_ioeventfd_match_and_release(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args);
#ifdef CONFIG_HAVE_KVM_IRQCHIP
int kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args);
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 9a2db57..dfd444b 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -448,12 +448,14 @@ enum {
kvm_ioeventfd_flag_nr_datamatch,
kvm_ioeventfd_flag_nr_pio,
kvm_ioeventfd_flag_nr_deassign,
+ kvm_ioeventfd_flag_nr_arch,
kvm_ioeventfd_flag_nr_max,
};
#define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
#define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
#define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
+#define KVM_IOEVENTFD_FLAG_ARCH (1 << kvm_ioeventfd_flag_nr_arch)
#define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1)
@@ -463,7 +465,7 @@ struct kvm_ioeventfd {
__u32 len; /* 1, 2, 4, or 8 bytes */
__s32 fd;
__u32 flags;
- __u8 pad[36];
+ __u8 data[36]; /* for architecture-specific data */
};
/* for KVM_ENABLE_CAP */
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index b6eea5c..63fe454 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -568,23 +568,37 @@ module_exit(irqfd_module_exit);
*
* userspace can register a PIO/MMIO address with an eventfd for receiving
* notification when the memory has been touched.
+ *
+ * Architectures that use a notification mechanism different from memory
+ * writes may override this with architecture-specific callbacks.
* --------------------------------------------------------------------
*/
-
-struct _ioeventfd {
- struct list_head list;
+#ifndef __KVM_HAVE_ARCH_IOEVENTFD
+struct kvm_arch_ioeventfd {
u64 addr;
int length;
- struct eventfd_ctx *eventfd;
u64 datamatch;
struct kvm_io_device dev;
bool wildcard;
};
+#endif
+
+struct _ioeventfd {
+ struct list_head list;
+ struct eventfd_ctx *eventfd;
+ struct kvm_arch_ioeventfd arch;
+};
-static inline struct _ioeventfd *
-to_ioeventfd(struct kvm_io_device *dev)
+static inline struct _ioeventfd *to_ioeventfd(struct kvm_arch_ioeventfd *arch)
{
- return container_of(dev, struct _ioeventfd, dev);
+ return container_of(arch, struct _ioeventfd, arch);
+}
+
+struct eventfd_ctx *kvm_ioeventfd_get_eventfd(struct kvm_arch_ioeventfd *arch)
+{
+ struct _ioeventfd *p = to_ioeventfd(arch);
+
+ return p->eventfd;
}
static void
@@ -595,16 +609,18 @@ ioeventfd_release(struct _ioeventfd *p)
kfree(p);
}
+#ifndef __KVM_HAVE_ARCH_IOEVENTFD
static bool
-ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
+ioeventfd_in_range(struct kvm_arch_ioeventfd *arch, gpa_t addr, int len,
+ const void *val)
{
u64 _val;
- if (!(addr == p->addr && len == p->length))
+ if (!(addr == arch->addr && len == arch->length))
/* address-range must be precise for a hit */
return false;
- if (p->wildcard)
+ if (arch->wildcard)
/* all else equal, wildcard is always a hit */
return true;
@@ -629,7 +645,13 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
return false;
}
- return _val == p->datamatch ? true : false;
+ return _val == arch->datamatch ? true : false;
+}
+
+static inline struct kvm_arch_ioeventfd *
+to_arch_ioeventfd(struct kvm_io_device *dev)
+{
+ return container_of(dev, struct kvm_arch_ioeventfd, dev);
}
/* MMIO/PIO writes trigger an event if the addr/val match */
@@ -637,12 +659,12 @@ static int
ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
const void *val)
{
- struct _ioeventfd *p = to_ioeventfd(this);
+ struct kvm_arch_ioeventfd *arch = to_arch_ioeventfd(this);
- if (!ioeventfd_in_range(p, addr, len, val))
+ if (!ioeventfd_in_range(arch, addr, len, val))
return -EOPNOTSUPP;
- eventfd_signal(p->eventfd, 1);
+ eventfd_signal(kvm_ioeventfd_get_eventfd(arch), 1);
return 0;
}
@@ -653,7 +675,7 @@ ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
static void
ioeventfd_destructor(struct kvm_io_device *this)
{
- struct _ioeventfd *p = to_ioeventfd(this);
+ struct _ioeventfd *p = to_ioeventfd(to_arch_ioeventfd(this));
ioeventfd_release(p);
}
@@ -663,6 +685,87 @@ static const struct kvm_io_device_ops ioeventfd_ops = {
.destructor = ioeventfd_destructor,
};
+int kvm_arch_ioeventfd_check(struct kvm_ioeventfd *args)
+{
+ if (args->flags & KVM_IOEVENTFD_FLAG_ARCH)
+ return -EINVAL;
+
+ /* must be natural-word sized */
+ switch (args->len) {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ /* check for range overflow */
+ if (args->addr + args->len < args->addr)
+ return -EINVAL;
+
+ return 0;
+}
+
+void kvm_arch_ioeventfd_init(struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args)
+{
+ arch->addr = args->addr;
+ arch->length = args->len;
+
+ /* The datamatch feature is optional, otherwise this is a wildcard */
+ if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
+ arch->datamatch = args->datamatch;
+ else
+ arch->wildcard = true;
+}
+
+int kvm_arch_ioeventfd_activate(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args)
+{
+ int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
+ enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
+
+ kvm_iodevice_init(&arch->dev, &ioeventfd_ops);
+
+ return kvm_io_bus_register_dev(kvm, bus_idx, arch->addr, arch->length,
+ &arch->dev);
+}
+
+bool kvm_arch_ioeventfd_match(struct kvm_arch_ioeventfd *arch,
+ struct kvm_arch_ioeventfd *to_match)
+{
+ if (to_match->addr == arch->addr &&
+ to_match->length == arch->length &&
+ (to_match->wildcard || arch->wildcard ||
+ to_match->datamatch == arch->datamatch))
+ return true;
+ return false;
+}
+
+bool kvm_arch_ioeventfd_match_and_release(struct kvm *kvm,
+ struct kvm_arch_ioeventfd *arch,
+ struct kvm_ioeventfd *args)
+{
+ int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
+ enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
+ bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
+
+ if (arch->addr != args->addr ||
+ arch->length != args->len ||
+ arch->wildcard != wildcard)
+ return false;
+
+ if (!arch->wildcard && arch->datamatch != args->datamatch)
+ return false;
+
+ kvm_io_bus_unregister_dev(kvm, bus_idx, &arch->dev);
+ return true;
+}
+#endif
+
/* assumes kvm->slots_lock held */
static bool
ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
@@ -670,9 +773,7 @@ ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
struct _ioeventfd *_p;
list_for_each_entry(_p, &kvm->ioeventfds, list)
- if (_p->addr == p->addr && _p->length == p->length &&
- (_p->wildcard || p->wildcard ||
- _p->datamatch == p->datamatch))
+ if (kvm_arch_ioeventfd_match(&p->arch, &_p->arch))
return true;
return false;
@@ -681,26 +782,13 @@ ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
static int
kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
{
- int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
- enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
struct _ioeventfd *p;
struct eventfd_ctx *eventfd;
int ret;
- /* must be natural-word sized */
- switch (args->len) {
- case 1:
- case 2:
- case 4:
- case 8:
- break;
- default:
- return -EINVAL;
- }
-
- /* check for range overflow */
- if (args->addr + args->len < args->addr)
- return -EINVAL;
+ ret = kvm_arch_ioeventfd_check(args);
+ if (ret)
+ return ret;
/* check for extra flags that we don't understand */
if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
@@ -717,15 +805,9 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
}
INIT_LIST_HEAD(&p->list);
- p->addr = args->addr;
- p->length = args->len;
p->eventfd = eventfd;
- /* The datamatch feature is optional, otherwise this is a wildcard */
- if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
- p->datamatch = args->datamatch;
- else
- p->wildcard = true;
+ kvm_arch_ioeventfd_init(&p->arch, args);
mutex_lock(&kvm->slots_lock);
@@ -735,10 +817,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
goto unlock_fail;
}
- kvm_iodevice_init(&p->dev, &ioeventfd_ops);
-
- ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
- &p->dev);
+ ret = kvm_arch_ioeventfd_activate(kvm, &p->arch, args);
if (ret < 0)
goto unlock_fail;
@@ -761,8 +840,6 @@ fail:
static int
kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
{
- int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
- enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
struct _ioeventfd *p, *tmp;
struct eventfd_ctx *eventfd;
int ret = -ENOENT;
@@ -774,18 +851,12 @@ kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
mutex_lock(&kvm->slots_lock);
list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
- bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
-
- if (p->eventfd != eventfd ||
- p->addr != args->addr ||
- p->length != args->len ||
- p->wildcard != wildcard)
+ if (p->eventfd != eventfd)
continue;
- if (!p->wildcard && p->datamatch != args->datamatch)
+ if (!kvm_arch_ioeventfd_match_and_release(kvm, &p->arch, args))
continue;
- kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
ioeventfd_release(p);
ret = 0;
break;
--
1.7.12.4
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