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KVM: kvm-io: support cookies 

Add new functions kvm_io_bus_{read,write}_cookie() that allows users of
the kvm io infrastructure to use a cookie value to speed up lookup of a
device on an io bus.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Cornelia Huck 2013-07-03 16:30:53 +02:00 committed by Paolo Bonzini
parent 1c118b8226
commit 126a5af520
2 changed files with 96 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/kvm_host.h
View File

@ -160,8 +160,12 @@ enum kvm_bus {
int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val);
int kvm_io_bus_write_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val, long cookie);
int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len,
void *val);
int kvm_io_bus_read_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, void *val, long cookie);
int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, struct kvm_io_device *dev);
int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,

108
virt/kvm/kvm_main.c
View File

@ -2863,11 +2863,48 @@ static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus,
return off;
}
static int __kvm_io_bus_write(struct kvm_io_bus *bus,
struct kvm_io_range *range, const void *val)
{
int idx;
idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
if (idx < 0)
return -EOPNOTSUPP;
while (idx < bus->dev_count &&
kvm_io_bus_sort_cmp(range, &bus->range[idx]) == 0) {
if (!kvm_iodevice_write(bus->range[idx].dev, range->addr,
range->len, val))
return idx;
idx++;
}
return -EOPNOTSUPP;
}
/* kvm_io_bus_write - called under kvm->slots_lock */
int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val)
{
int idx;
struct kvm_io_bus *bus;
struct kvm_io_range range;
int r;
range = (struct kvm_io_range) {
.addr = addr,
.len = len,
};
bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
r = __kvm_io_bus_write(bus, &range, val);
return r < 0 ? r : 0;
}
/* kvm_io_bus_write_cookie - called under kvm->slots_lock */
int kvm_io_bus_write_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val, long cookie)
{
struct kvm_io_bus *bus;
struct kvm_io_range range;
@ -2877,14 +2914,35 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
};
bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
idx = kvm_io_bus_get_first_dev(bus, addr, len);
/* First try the device referenced by cookie. */
if ((cookie >= 0) && (cookie < bus->dev_count) &&
(kvm_io_bus_sort_cmp(&range, &bus->range[cookie]) == 0))
if (!kvm_iodevice_write(bus->range[cookie].dev, addr, len,
val))
return cookie;
/*
* cookie contained garbage; fall back to search and return the
* correct cookie value.
*/
return __kvm_io_bus_write(bus, &range, val);
}
static int __kvm_io_bus_read(struct kvm_io_bus *bus, struct kvm_io_range *range,
void *val)
{
int idx;
idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
if (idx < 0)
return -EOPNOTSUPP;
while (idx < bus->dev_count &&
kvm_io_bus_sort_cmp(&range, &bus->range[idx]) == 0) {
if (!kvm_iodevice_write(bus->range[idx].dev, addr, len, val))
return 0;
kvm_io_bus_sort_cmp(range, &bus->range[idx]) == 0) {
if (!kvm_iodevice_read(bus->range[idx].dev, range->addr,
range->len, val))
return idx;
idx++;
}
@ -2895,7 +2953,24 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, void *val)
{
int idx;
struct kvm_io_bus *bus;
struct kvm_io_range range;
int r;
range = (struct kvm_io_range) {
.addr = addr,
.len = len,
};
bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
r = __kvm_io_bus_read(bus, &range, val);
return r < 0 ? r : 0;
}
/* kvm_io_bus_read_cookie - called under kvm->slots_lock */
int kvm_io_bus_read_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, void *val, long cookie)
{
struct kvm_io_bus *bus;
struct kvm_io_range range;
@ -2905,18 +2980,19 @@ int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
};
bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
idx = kvm_io_bus_get_first_dev(bus, addr, len);
if (idx < 0)
return -EOPNOTSUPP;
while (idx < bus->dev_count &&
kvm_io_bus_sort_cmp(&range, &bus->range[idx]) == 0) {
if (!kvm_iodevice_read(bus->range[idx].dev, addr, len, val))
return 0;
idx++;
}
/* First try the device referenced by cookie. */
if ((cookie >= 0) && (cookie < bus->dev_count) &&
(kvm_io_bus_sort_cmp(&range, &bus->range[cookie]) == 0))
if (!kvm_iodevice_read(bus->range[cookie].dev, addr, len,
val))
return cookie;
return -EOPNOTSUPP;
/*
* cookie contained garbage; fall back to search and return the
* correct cookie value.
*/
return __kvm_io_bus_read(bus, &range, val);
}
/* Caller must hold slots_lock. */