[PATCH 4.2 005/258] kvm: factor out core eventfd assign/deassign logic

From: Greg Kroah-Hartman
Date: Sun Oct 18 2015 - 00:54:10 EST


4.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@xxxxxxxxxx>

commit 85da11ca587c8eb73993a1b503052391a73586f9 upstream.

This patch factors out core eventfd assign/deassign logic and leaves
the argument checking and bus index selection to callers.

Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
virt/kvm/eventfd.c | 85 +++++++++++++++++++++++++++++++----------------------
1 file changed, 50 insertions(+), 35 deletions(-)

--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -771,40 +771,14 @@ static enum kvm_bus ioeventfd_bus_from_f
return KVM_MMIO_BUS;
}

-static int
-kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
+ enum kvm_bus bus_idx,
+ struct kvm_ioeventfd *args)
{
- enum kvm_bus bus_idx;
- struct _ioeventfd *p;
- struct eventfd_ctx *eventfd;
- int ret;

- bus_idx = ioeventfd_bus_from_flags(args->flags);
- /* must be natural-word sized, or 0 to ignore length */
- switch (args->len) {
- case 0:
- 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;
-
- /* ioeventfd with no length can't be combined with DATAMATCH */
- if (!args->len &&
- args->flags & (KVM_IOEVENTFD_FLAG_PIO |
- KVM_IOEVENTFD_FLAG_DATAMATCH))
- return -EINVAL;
+ struct eventfd_ctx *eventfd;
+ struct _ioeventfd *p;
+ int ret;

eventfd = eventfd_ctx_fdget(args->fd);
if (IS_ERR(eventfd))
@@ -873,14 +847,13 @@ fail:
}

static int
-kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
+ struct kvm_ioeventfd *args)
{
- enum kvm_bus bus_idx;
struct _ioeventfd *p, *tmp;
struct eventfd_ctx *eventfd;
int ret = -ENOENT;

- bus_idx = ioeventfd_bus_from_flags(args->flags);
eventfd = eventfd_ctx_fdget(args->fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
@@ -918,6 +891,48 @@ kvm_deassign_ioeventfd(struct kvm *kvm,
return ret;
}

+static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+{
+ enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags);
+
+ return kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);
+}
+
+static int
+kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
+{
+ enum kvm_bus bus_idx;
+
+ bus_idx = ioeventfd_bus_from_flags(args->flags);
+ /* must be natural-word sized, or 0 to ignore length */
+ switch (args->len) {
+ case 0:
+ 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;
+
+ /* ioeventfd with no length can't be combined with DATAMATCH */
+ if (!args->len &&
+ args->flags & (KVM_IOEVENTFD_FLAG_PIO |
+ KVM_IOEVENTFD_FLAG_DATAMATCH))
+ return -EINVAL;
+
+ return kvm_assign_ioeventfd_idx(kvm, bus_idx, args);
+}
+
int
kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
{


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