[PATCH 2/5] ioeventfd: Add helper functions for reading and writing

Sasha Levin
2011-07-06T04:38:10Z

Add get_val() and set_val() to help getting and setting a natural
sized variable pointed by a void ptr.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
virt/kvm/eventfd.c | 57 ++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 5fb09b4..a1a3f66 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -444,23 +444,10 @@ ioeventfd_release(struct _ioeventfd *p)
kfree(p);
}

-static bool
-ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
+static u64 get_val(const void *val, int len)
{
u64 _val;

- if (!((addr >= p->addr) && ((addr + len) <= (p->addr + p->length))))
- /* the entire address-range must be within the ioeventfd */
- 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;
@@ -475,8 +462,48 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
_val = *(u64 *)val;
break;
default:
- return false;
+ return 0;
+ }
+
+ return _val;
+}
+
+static void set_val(void *val, int len, u64 new_val)
+{
+ switch (len) {
+ case 1:
+ *(u8 *)val = new_val;
+ break;
+ case 2:
+ *(u16 *)val = new_val;
+ break;
+ case 4:
+ *(u32 *)val = new_val;
+ break;
+ case 8:
+ *(u64 *)val = new_val;
+ break;
}
+}
+
+static bool
+ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
+{
+ u64 _val;
+
+ if (!((addr >= p->addr) && ((addr + len) <= (p->addr + p->length))))
+ /* the entire address-range must be within the ioeventfd */
+ 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));
+
+ _val = get_val(val, len);

return _val == p->datamatch ? true : false;
}
--
1.7.6