| Message ID | 1372841780-29645-2-git-send-email-cornelia.huck@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 03/07/2013 10:56, Cornelia Huck ha scritto: > Add a new function kvm_io_bus_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> > --- > include/linux/kvm_host.h | 2 ++ > virt/kvm/kvm_main.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 46 insertions(+) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index e3aae6d..2d298fc 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -159,6 +159,8 @@ 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_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 1580dd4..222475a 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2891,6 +2891,50 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, > return -EOPNOTSUPP; > } > > +/* 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) > +{ > + int idx, ret = -EOPNOTSUPP; > + struct kvm_io_bus *bus; > + struct kvm_io_range range; > + > + 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_write(bus->range[*cookie].dev, addr, len, > + val)) > + return 0; Nice idea, though I don't really like the duplication between kvm_io_bus_write and kvm_io_bus_write_cookie. Can you make kvm_io_bus_write, and perhaps kvm_io_bus_read too, return the cookie, and return -EINVAL here if the cookie is garbage? (Unfortunately, most callers of kvm_io_bus_read/write expect them to never return a value that is >= 0, but there aren't many so it's easily solved). Paolo > + > + /* > + * *cookie contained garbage; fall back to search and return the > + * correct value in *cookie. > + */ > + idx = kvm_io_bus_get_first_dev(bus, addr, len); > + if (idx < 0) > + goto out; > + > + 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)) { > + ret = 0; > + goto out; > + } > + idx++; > + } > + idx = -ENOENT; > +out: > + *cookie = idx; > + return ret; > +} > + > /* kvm_io_bus_read - called under kvm->slots_lock */ > int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, > int len, void *val) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Il 03/07/2013 11:05, Paolo Bonzini ha scritto: > Nice idea, though I don't really like the duplication between > kvm_io_bus_write and kvm_io_bus_write_cookie. > > Can you make kvm_io_bus_write, and perhaps kvm_io_bus_read too, return > the cookie, and return -EINVAL here if the cookie is garbage? On second though---no need to return -EINVAL, you can just pass the cookie by value and tail-call kvm_io_bus_write. Whatever makes the s390 code look nicer. Paolo > (Unfortunately, most callers of kvm_io_bus_read/write expect them to > never return a value that is >= 0, but there aren't many so it's easily > solved). -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index e3aae6d..2d298fc 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -159,6 +159,8 @@ 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_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 1580dd4..222475a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2891,6 +2891,50 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, return -EOPNOTSUPP; } +/* 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) +{ + int idx, ret = -EOPNOTSUPP; + struct kvm_io_bus *bus; + struct kvm_io_range range; + + 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_write(bus->range[*cookie].dev, addr, len, + val)) + return 0; + + /* + * *cookie contained garbage; fall back to search and return the + * correct value in *cookie. + */ + idx = kvm_io_bus_get_first_dev(bus, addr, len); + if (idx < 0) + goto out; + + 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)) { + ret = 0; + goto out; + } + idx++; + } + idx = -ENOENT; +out: + *cookie = idx; + return ret; +} + /* kvm_io_bus_read - called under kvm->slots_lock */ int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len, void *val)
Add a new function kvm_io_bus_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> --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 46 insertions(+)