[PATCH v2 07/17] IB/core: Add flags for on demand paging support

Haggai Eran
2014-11-11T16:36:13Z

From: Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

* Add a configuration option for enable on-demand paging support in the
infiniband subsystem (CONFIG_INFINIBAND_ON_DEMAND_PAGING). In a later patch,
this configuration option will select the MMU_NOTIFIER configuration option
to enable mmu notifiers.
* Add a flag for on demand paging (ODP) support in the IB device capabilities.
* Add a flag to request ODP MR in the access flags to reg_mr.
* Fail registrations done with the ODP flag when the low-level driver doesn't
support this.
* Change the conditions in which an MR will be writable to explicitly
specify the access flags. This is to avoid making an MR writable just
because it is an ODP MR.
* Add a ODP capabilities to the extended query device verb.

Signed-off-by: Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Shachar Raindel <raindel-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Haggai Eran <haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
---
drivers/infiniband/Kconfig | 10 ++++++++++
drivers/infiniband/core/umem.c | 8 +++++---
drivers/infiniband/core/uverbs_cmd.c | 25 +++++++++++++++++++++++++
include/rdma/ib_verbs.h | 28 ++++++++++++++++++++++++++--
include/uapi/rdma/ib_user_verbs.h | 16 ++++++++++++++++
5 files changed, 82 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/Kconfig b/drivers/infiniband/Kconfig
index 77089399359b..089a2c2af329 100644
--- a/drivers/infiniband/Kconfig
+++ b/drivers/infiniband/Kconfig
@@ -38,6 +38,16 @@ config INFINIBAND_USER_MEM
depends on INFINIBAND_USER_ACCESS != n
default y

+config INFINIBAND_ON_DEMAND_PAGING
+ bool "InfiniBand on-demand paging support"
+ depends on INFINIBAND_USER_MEM
+ default y
+ ---help---
+ On demand paging support for the InfiniBand subsystem.
+ Together with driver support this allows registration of
+ memory regions without pinning their pages, fetching the
+ pages on demand instead.
+
config INFINIBAND_ADDR_TRANS
bool
depends on INFINIBAND
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 77bec75963e7..a140b2d4d94e 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -107,13 +107,15 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
umem->page_size = PAGE_SIZE;
umem->pid = get_task_pid(current, PIDTYPE_PID);
/*
- * We ask for writable memory if any access flags other than
- * "remote read" are set. "Local write" and "remote write"
+ * We ask for writable memory if any of the following
+ * access flags are set. "Local write" and "remote write"
* obviously require write access. "Remote atomic" can do
* things like fetch and add, which will modify memory, and
* "MW bind" can change permissions by binding a window.
*/
- umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ);
+ umem->writable = !!(access &
+ (IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE |
+ IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));

/* We assume the memory is from hugetlb until proved otherwise */
umem->hugetlb = 1;
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 74ad0d0de92b..46b60086a4bf 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -953,6 +953,18 @@ ssize_t ib_uverbs_reg_mr(struct ib_uverbs_file *file,
goto err_free;
}

+ if (cmd.access_flags & IB_ACCESS_ON_DEMAND) {
+ struct ib_device_attr attr;
+
+ ret = ib_query_device(pd->device, &attr);
+ if (ret || !(attr.device_cap_flags &
+ IB_DEVICE_ON_DEMAND_PAGING)) {
+ pr_debug("ODP support not available\n");
+ ret = -EINVAL;
+ goto err_put;
+ }
+ }
+
mr = pd->device->reg_user_mr(pd, cmd.start, cmd.length, cmd.hca_va,
cmd.access_flags, &udata);
if (IS_ERR(mr)) {
@@ -3286,6 +3298,19 @@ int ib_uverbs_ex_query_device(struct ib_uverbs_file *file,
copy_query_dev_fields(file, &resp.base, &attr);
resp.comp_mask = 0;

+#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
+ if (cmd.comp_mask & IB_USER_VERBS_EX_QUERY_DEVICE_ODP) {
+ resp.odp_caps.general_caps = attr.odp_caps.general_caps;
+ resp.odp_caps.per_transport_caps.rc_odp_caps =
+ attr.odp_caps.per_transport_caps.rc_odp_caps;
+ resp.odp_caps.per_transport_caps.uc_odp_caps =
+ attr.odp_caps.per_transport_caps.uc_odp_caps;
+ resp.odp_caps.per_transport_caps.ud_odp_caps =
+ attr.odp_caps.per_transport_caps.ud_odp_caps;
+ resp.comp_mask |= IB_USER_VERBS_EX_QUERY_DEVICE_ODP;
+ }
+#endif
+
err = ib_copy_to_udata(ucore, &resp, sizeof(resp));
if (err)
return err;
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 97a999f9e4d8..a41bc5a39ebf 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -123,7 +123,8 @@ enum ib_device_cap_flags {
IB_DEVICE_MEM_WINDOW_TYPE_2A = (1<<23),
IB_DEVICE_MEM_WINDOW_TYPE_2B = (1<<24),
IB_DEVICE_MANAGED_FLOW_STEERING = (1<<29),
- IB_DEVICE_SIGNATURE_HANDOVER = (1<<30)
+ IB_DEVICE_SIGNATURE_HANDOVER = (1<<30),
+ IB_DEVICE_ON_DEMAND_PAGING = (1<<31),
};

enum ib_signature_prot_cap {
@@ -143,6 +144,27 @@ enum ib_atomic_cap {
IB_ATOMIC_GLOB
};

+enum ib_odp_general_cap_bits {
+ IB_ODP_SUPPORT = 1 << 0,
+};
+
+enum ib_odp_transport_cap_bits {
+ IB_ODP_SUPPORT_SEND = 1 << 0,
+ IB_ODP_SUPPORT_RECV = 1 << 1,
+ IB_ODP_SUPPORT_WRITE = 1 << 2,
+ IB_ODP_SUPPORT_READ = 1 << 3,
+ IB_ODP_SUPPORT_ATOMIC = 1 << 4,
+};
+
+struct ib_odp_caps {
+ uint64_t general_caps;
+ struct {
+ uint32_t rc_odp_caps;
+ uint32_t uc_odp_caps;
+ uint32_t ud_odp_caps;
+ } per_transport_caps;
+};
+
struct ib_device_attr {
u64 fw_ver;
__be64 sys_image_guid;
@@ -186,6 +208,7 @@ struct ib_device_attr {
u8 local_ca_ack_delay;
int sig_prot_cap;
int sig_guard_cap;
+ struct ib_odp_caps odp_caps;
};

enum ib_mtu {
@@ -1073,7 +1096,8 @@ enum ib_access_flags {
IB_ACCESS_REMOTE_READ = (1<<2),
IB_ACCESS_REMOTE_ATOMIC = (1<<3),
IB_ACCESS_MW_BIND = (1<<4),
- IB_ZERO_BASED = (1<<5)
+ IB_ZERO_BASED = (1<<5),
+ IB_ACCESS_ON_DEMAND = (1<<6),
};

struct ib_phys_buf {
diff --git a/include/uapi/rdma/ib_user_verbs.h b/include/uapi/rdma/ib_user_verbs.h
index ed8c3d9da42c..cd542dd28ed4 100644
--- a/include/uapi/rdma/ib_user_verbs.h
+++ b/include/uapi/rdma/ib_user_verbs.h
@@ -202,13 +202,29 @@ struct ib_uverbs_query_device_resp {
__u8 reserved[4];
};

+enum {
+ IB_USER_VERBS_EX_QUERY_DEVICE_ODP = 1ULL << 0,
+};
+
struct ib_uverbs_ex_query_device {
__u32 comp_mask;
};

+struct ib_uverbs_odp_caps {
+ __u64 general_caps;
+ struct {
+ __u32 rc_odp_caps;
+ __u32 uc_odp_caps;
+ __u32 ud_odp_caps;
+ } per_transport_caps;
+ __u32 reserved;
+};
+
struct ib_uverbs_ex_query_device_resp {
struct ib_uverbs_query_device_resp base;
__u32 comp_mask;
+ __u32 reserved;
+ struct ib_uverbs_odp_caps odp_caps;
};

struct ib_uverbs_query_port {