On Wed, Jul 03, 2013 at 04:30:53PM +0200, Cornelia Huck wrote:
> 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@xxxxxxxxxx>
Looks good to me now.
> ---
> include/linux/kvm_host.h | 4 ++
> virt/kvm/kvm_main.c | 106 ++++++++++++++++++++++++++++++++++++++++-------
> 2 files changed, 95 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index e3aae6d..60e261c9 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -159,8 +159,12 @@ 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,
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 1580dd4..c7f5355 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -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;
> + if (!kvm_iodevice_read(bus->range[idx].dev, range->addr,
> + range->len, val))
> + return idx;
> idx++;
> }
>
> @@ -2895,9 +2953,9 @@ 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,
> @@ -2905,18 +2963,36 @@ 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;
> + r = __kvm_io_bus_read(bus, &range, val);
> + return r < 0 ? r : 0;
> +}
>
> - 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++;
> - }
> +/* 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;
>
> - return -EOPNOTSUPP;
> + range = (struct kvm_io_range) {
> + .addr = addr,
> + .len = len,
> + };
> +
> + bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
> +
> + /* 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;
> +
> + /*
> + * 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. */
> --
> 1.8.2.2
--
Gleb.
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