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-rw-r--r--arch/x86/kvm/x86.c1
-rw-r--r--include/linux/kvm.h24
-rw-r--r--include/linux/kvm_host.h10
-rw-r--r--virt/kvm/eventfd.c251
-rw-r--r--virt/kvm/kvm_main.c11
5 files changed, 293 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2214384ff610..42160b031fcd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1212,6 +1212,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_IRQ_INJECT_STATUS:
case KVM_CAP_ASSIGN_DEV_IRQ:
case KVM_CAP_IRQFD:
+ case KVM_CAP_IOEVENTFD:
case KVM_CAP_PIT2:
case KVM_CAP_PIT_STATE2:
r = 1;
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index a74a1fcc28e9..230a91aa61c9 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -307,6 +307,28 @@ struct kvm_guest_debug {
struct kvm_guest_debug_arch arch;
};
+enum {
+ kvm_ioeventfd_flag_nr_datamatch,
+ kvm_ioeventfd_flag_nr_pio,
+ kvm_ioeventfd_flag_nr_deassign,
+ 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_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1)
+
+struct kvm_ioeventfd {
+ __u64 datamatch;
+ __u64 addr; /* legal pio/mmio address */
+ __u32 len; /* 1, 2, 4, or 8 bytes */
+ __s32 fd;
+ __u32 flags;
+ __u8 pad[36];
+};
+
#define KVM_TRC_SHIFT 16
/*
* kvm trace categories
@@ -412,6 +434,7 @@ struct kvm_guest_debug {
#ifdef __KVM_HAVE_PIT_STATE2
#define KVM_CAP_PIT_STATE2 35
#endif
+#define KVM_CAP_IOEVENTFD 36
#ifdef KVM_CAP_IRQ_ROUTING
@@ -520,6 +543,7 @@ struct kvm_irqfd {
#define KVM_IRQFD _IOW(KVMIO, 0x76, struct kvm_irqfd)
#define KVM_CREATE_PIT2 _IOW(KVMIO, 0x77, struct kvm_pit_config)
#define KVM_SET_BOOT_CPU_ID _IO(KVMIO, 0x78)
+#define KVM_IOEVENTFD _IOW(KVMIO, 0x79, struct kvm_ioeventfd)
/*
* ioctls for vcpu fds
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 983b0bdeb3ff..6ec9fc56a49e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -155,6 +155,7 @@ struct kvm {
spinlock_t lock;
struct list_head items;
} irqfds;
+ struct list_head ioeventfds;
#endif
struct kvm_vm_stat stat;
struct kvm_arch arch;
@@ -528,19 +529,24 @@ static inline void kvm_free_irq_routing(struct kvm *kvm) {}
#ifdef CONFIG_HAVE_KVM_EVENTFD
-void kvm_irqfd_init(struct kvm *kvm);
+void kvm_eventfd_init(struct kvm *kvm);
int kvm_irqfd(struct kvm *kvm, int fd, int gsi, int flags);
void kvm_irqfd_release(struct kvm *kvm);
+int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args);
#else
-static inline void kvm_irqfd_init(struct kvm *kvm) {}
+static inline void kvm_eventfd_init(struct kvm *kvm) {}
static inline int kvm_irqfd(struct kvm *kvm, int fd, int gsi, int flags)
{
return -EINVAL;
}
static inline void kvm_irqfd_release(struct kvm *kvm) {}
+static inline int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+{
+ return -ENOSYS;
+}
#endif /* CONFIG_HAVE_KVM_EVENTFD */
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 4092b8dcd510..99017e8a92ac 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -21,6 +21,7 @@
*/
#include <linux/kvm_host.h>
+#include <linux/kvm.h>
#include <linux/workqueue.h>
#include <linux/syscalls.h>
#include <linux/wait.h>
@@ -28,6 +29,9 @@
#include <linux/file.h>
#include <linux/list.h>
#include <linux/eventfd.h>
+#include <linux/kernel.h>
+
+#include "iodev.h"
/*
* --------------------------------------------------------------------
@@ -234,10 +238,11 @@ fail:
}
void
-kvm_irqfd_init(struct kvm *kvm)
+kvm_eventfd_init(struct kvm *kvm)
{
spin_lock_init(&kvm->irqfds.lock);
INIT_LIST_HEAD(&kvm->irqfds.items);
+ INIT_LIST_HEAD(&kvm->ioeventfds);
}
/*
@@ -327,3 +332,247 @@ static void __exit irqfd_module_exit(void)
module_init(irqfd_module_init);
module_exit(irqfd_module_exit);
+
+/*
+ * --------------------------------------------------------------------
+ * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
+ *
+ * userspace can register a PIO/MMIO address with an eventfd for receiving
+ * notification when the memory has been touched.
+ * --------------------------------------------------------------------
+ */
+
+struct _ioeventfd {
+ struct list_head list;
+ u64 addr;
+ int length;
+ struct eventfd_ctx *eventfd;
+ u64 datamatch;
+ struct kvm_io_device dev;
+ bool wildcard;
+};
+
+static inline struct _ioeventfd *
+to_ioeventfd(struct kvm_io_device *dev)
+{
+ return container_of(dev, struct _ioeventfd, dev);
+}
+
+static void
+ioeventfd_release(struct _ioeventfd *p)
+{
+ eventfd_ctx_put(p->eventfd);
+ list_del(&p->list);
+ kfree(p);
+}
+
+static bool
+ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
+{
+ u64 _val;
+
+ if (!(addr == p->addr && len == p->length))
+ /* address-range must be precise for a hit */
+ return false;
+
+ if (p->wildcard)
+ /* all else equal, wildcard is always a hit */
+ return true;
+
+ /* otherwise, we have to actually compare the data */
+
+ BUG_ON(!IS_ALIGNED((unsigned long)val, len));
+
+ switch (len) {
+ case 1:
+ _val = *(u8 *)val;
+ break;
+ case 2:
+ _val = *(u16 *)val;
+ break;
+ case 4:
+ _val = *(u32 *)val;
+ break;
+ case 8:
+ _val = *(u64 *)val;
+ break;
+ default:
+ return false;
+ }
+
+ return _val == p->datamatch ? true : false;
+}
+
+/* MMIO/PIO writes trigger an event if the addr/val match */
+static int
+ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
+ const void *val)
+{
+ struct _ioeventfd *p = to_ioeventfd(this);
+
+ if (!ioeventfd_in_range(p, addr, len, val))
+ return -EOPNOTSUPP;
+
+ eventfd_signal(p->eventfd, 1);
+ return 0;
+}
+
+/*
+ * This function is called as KVM is completely shutting down. We do not
+ * need to worry about locking just nuke anything we have as quickly as possible
+ */
+static void
+ioeventfd_destructor(struct kvm_io_device *this)
+{
+ struct _ioeventfd *p = to_ioeventfd(this);
+
+ ioeventfd_release(p);
+}
+
+static const struct kvm_io_device_ops ioeventfd_ops = {
+ .write = ioeventfd_write,
+ .destructor = ioeventfd_destructor,
+};
+
+/* assumes kvm->slots_lock held */
+static bool
+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))
+ return true;
+
+ return false;
+}
+
+static int
+kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+{
+ int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
+ struct kvm_io_bus *bus = 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;
+
+ /* check for extra flags that we don't understand */
+ if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
+ return -EINVAL;
+
+ eventfd = eventfd_ctx_fdget(args->fd);
+ if (IS_ERR(eventfd))
+ return PTR_ERR(eventfd);
+
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ 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;
+
+ down_write(&kvm->slots_lock);
+
+ /* Verify that there isnt a match already */
+ if (ioeventfd_check_collision(kvm, p)) {
+ ret = -EEXIST;
+ goto unlock_fail;
+ }
+
+ kvm_iodevice_init(&p->dev, &ioeventfd_ops);
+
+ ret = __kvm_io_bus_register_dev(bus, &p->dev);
+ if (ret < 0)
+ goto unlock_fail;
+
+ list_add_tail(&p->list, &kvm->ioeventfds);
+
+ up_write(&kvm->slots_lock);
+
+ return 0;
+
+unlock_fail:
+ up_write(&kvm->slots_lock);
+
+fail:
+ kfree(p);
+ eventfd_ctx_put(eventfd);
+
+ return ret;
+}
+
+static int
+kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+{
+ int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
+ struct kvm_io_bus *bus = pio ? &kvm->pio_bus : &kvm->mmio_bus;
+ struct _ioeventfd *p, *tmp;
+ struct eventfd_ctx *eventfd;
+ int ret = -ENOENT;
+
+ eventfd = eventfd_ctx_fdget(args->fd);
+ if (IS_ERR(eventfd))
+ return PTR_ERR(eventfd);
+
+ down_write(&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)
+ continue;
+
+ if (!p->wildcard && p->datamatch != args->datamatch)
+ continue;
+
+ __kvm_io_bus_unregister_dev(bus, &p->dev);
+ ioeventfd_release(p);
+ ret = 0;
+ break;
+ }
+
+ up_write(&kvm->slots_lock);
+
+ eventfd_ctx_put(eventfd);
+
+ return ret;
+}
+
+int
+kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+{
+ if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
+ return kvm_deassign_ioeventfd(kvm, args);
+
+ return kvm_assign_ioeventfd(kvm, args);
+}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 9c2fd025b8ae..d7b9bbba26da 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -979,7 +979,7 @@ static struct kvm *kvm_create_vm(void)
spin_lock_init(&kvm->mmu_lock);
spin_lock_init(&kvm->requests_lock);
kvm_io_bus_init(&kvm->pio_bus);
- kvm_irqfd_init(kvm);
+ kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
mutex_init(&kvm->irq_lock);
kvm_io_bus_init(&kvm->mmio_bus);
@@ -2271,6 +2271,15 @@ static long kvm_vm_ioctl(struct file *filp,
r = kvm_irqfd(kvm, data.fd, data.gsi, data.flags);
break;
}
+ case KVM_IOEVENTFD: {
+ struct kvm_ioeventfd data;
+
+ r = -EFAULT;
+ if (copy_from_user(&data, argp, sizeof data))
+ goto out;
+ r = kvm_ioeventfd(kvm, &data);
+ break;
+ }
#ifdef CONFIG_KVM_APIC_ARCHITECTURE
case KVM_SET_BOOT_CPU_ID:
r = 0;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 18:42:13 +0000