diff mbox series

[RFC,11/13] fwctl/cxl: Add query commands software command for ->fw_rpc()

Message ID 20240718213446.1750135-12-dave.jiang@intel.com
State New, archived
Headers show
Series fwctl/cxl: Add CXL feature commands support via fwctl | expand

Commit Message

Dave Jiang July 18, 2024, 9:32 p.m. UTC
Add a software command through the ->fw_rpc() in order for the user to
retrieve information about the commands that are supported. In this
instance only 3 commands are supported: Get Supported Features, Get
Feature, and Set Feature.

The expected flow of operation is to send the call first with 0 set
to the n_commands parameter to indicate query of total commands
available. And then a second call provides the number of commands
to retrieve with the appropriate amount of memory allocated to store
information about the commands.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/cxl/core/mbox.c     | 80 +++++++++++++++++++++++++++++++++++++
 drivers/fwctl/cxl/cxl.c     | 42 ++++++++++++++++---
 include/linux/cxl/mailbox.h |  3 ++
 include/uapi/fwctl/cxl.h    |  5 ++-
 4 files changed, 124 insertions(+), 6 deletions(-)

Comments

Jason Gunthorpe July 22, 2024, 3:24 p.m. UTC | #1
On Thu, Jul 18, 2024 at 02:32:29PM -0700, Dave Jiang wrote:
> Add a software command through the ->fw_rpc() in order for the user to
> retrieve information about the commands that are supported. In this
> instance only 3 commands are supported: Get Supported Features, Get
> Feature, and Set Feature.

I wonder if we should try to have a seperate API for this, knowing
what command numbers are supported seems sort of general to me?

Jason
Dave Jiang July 22, 2024, 11:23 p.m. UTC | #2
On 7/22/24 8:24 AM, Jason Gunthorpe wrote:
> On Thu, Jul 18, 2024 at 02:32:29PM -0700, Dave Jiang wrote:
>> Add a software command through the ->fw_rpc() in order for the user to
>> retrieve information about the commands that are supported. In this
>> instance only 3 commands are supported: Get Supported Features, Get
>> Feature, and Set Feature.
> 
> I wonder if we should try to have a seperate API for this, knowing
> what command numbers are supported seems sort of general to me?

Probably a reasonable thing to add. Will you add something in the fwctl v3 or should I try to add something in my series for fwctl?

Wonder if we should also return some sort of fwctl commonly defined effects field for each command.

> 
> Jason
Jonathan Cameron July 29, 2024, 11:48 a.m. UTC | #3
On Thu, 18 Jul 2024 14:32:29 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> Add a software command through the ->fw_rpc() in order for the user to
> retrieve information about the commands that are supported. In this
> instance only 3 commands are supported: Get Supported Features, Get
> Feature, and Set Feature.
> 
> The expected flow of operation is to send the call first with 0 set
> to the n_commands parameter to indicate query of total commands
> available. And then a second call provides the number of commands
> to retrieve with the appropriate amount of memory allocated to store
> information about the commands.

We will need another layer of querying to query what features
are supported for each type of access. Get is probably always reasonable
in some cases we may want to block Set even with taint as it may provide
a nasty footgun.

Jonathan
Jason Gunthorpe Aug. 8, 2024, 12:56 p.m. UTC | #4
On Mon, Jul 22, 2024 at 04:23:14PM -0700, Dave Jiang wrote:
> 
> 
> On 7/22/24 8:24 AM, Jason Gunthorpe wrote:
> > On Thu, Jul 18, 2024 at 02:32:29PM -0700, Dave Jiang wrote:
> >> Add a software command through the ->fw_rpc() in order for the user to
> >> retrieve information about the commands that are supported. In this
> >> instance only 3 commands are supported: Get Supported Features, Get
> >> Feature, and Set Feature.
> > 
> > I wonder if we should try to have a seperate API for this, knowing
> > what command numbers are supported seems sort of general to me?
> 
> Probably a reasonable thing to add. Will you add something in the
> fwctl v3 or should I try to add something in my series for fwctl?
> 
> Wonder if we should also return some sort of fwctl commonly defined
> effects field for each command.

I'm not sure I fully understand what CXL would like here, including
Jonathan's remakrs too. Can you give some short draft?

Jason
diff mbox series

Patch

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index d77817e347d8..91be8cfbc2bb 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -655,6 +655,86 @@  int cxl_query_cmd(struct cxl_mailbox *cxl_mbox,
 	return 0;
 }
 
+static bool fwctl_supported_commands(u16 opcode)
+{
+	switch (opcode) {
+	case CXL_MBOX_OP_GET_SUPPORTED_FEATURES:
+	case CXL_MBOX_OP_GET_FEATURE:
+	case CXL_MBOX_OP_SET_FEATURE:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static int get_fwctl_supported_commands(void)
+{
+	struct cxl_mem_command *cmd;
+	int cmds = 0;
+
+	cxl_for_each_cmd(cmd) {
+		if (fwctl_supported_commands(cmd->opcode))
+			cmds++;
+	}
+
+	return cmds;
+}
+
+void *cxl_query_cmd_from_fwctl(struct cxl_mailbox *cxl_mbox,
+			       struct cxl_mem_query_commands *q,
+			       size_t *out_len)
+{
+	u32 n_commands = q->n_commands;
+	struct cxl_mem_command *cmd;
+	size_t output_size;
+	int commands;
+	int j = 0;
+
+	commands = get_fwctl_supported_commands();
+	if (n_commands > commands)
+		return ERR_PTR(-EINVAL);
+
+	output_size = sizeof(struct cxl_mem_query_commands) +
+		      n_commands * sizeof(struct cxl_command_info);
+
+	struct cxl_mem_query_commands *qout __free(kvfree) =
+		kvzalloc(output_size, GFP_KERNEL);
+
+	if (!qout)
+		return ERR_PTR(-ENOMEM);
+
+	*out_len = output_size;
+	if (n_commands == 0) {
+		qout->n_commands = commands;
+		return no_free_ptr(qout);
+	}
+
+	qout->n_commands = n_commands;
+
+	/*
+	 * otherwise, return min(n_commands, total commands) cxl_command_info
+	 * structures.
+	 */
+	cxl_for_each_cmd(cmd) {
+		struct cxl_command_info info = cmd->info;
+
+		if (fwctl_supported_commands(cmd->opcode)) {
+			if (test_bit(info.id, cxl_mbox->enabled_cmds))
+				info.flags |= CXL_MEM_COMMAND_FLAG_ENABLED;
+			if (test_bit(info.id, cxl_mbox->exclusive_cmds))
+				info.flags |= CXL_MEM_COMMAND_FLAG_EXCLUSIVE;
+
+			memcpy(&qout->commands[j++], &info, sizeof(info));
+		}
+
+		if (j == n_commands)
+			break;
+	}
+
+	return no_free_ptr(qout);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_query_cmd_from_fwctl, CXL);
+
 /**
  * handle_mailbox_cmd_from_user() - Dispatch a mailbox command for userspace.
  * @mailbox: The mailbox context for the operation.
diff --git a/drivers/fwctl/cxl/cxl.c b/drivers/fwctl/cxl/cxl.c
index 01f0771148e1..8836a806763f 100644
--- a/drivers/fwctl/cxl/cxl.c
+++ b/drivers/fwctl/cxl/cxl.c
@@ -135,6 +135,24 @@  static bool cxlctl_validate_hw_cmds(struct cxl_mailbox *cxl_mbox,
 	return false;
 }
 
+static bool cxlctl_validate_query_commands(struct fwctl_rpc_cxl *rpc_in)
+{
+	int cmds;
+
+	if (rpc_in->payload_size < sizeof(rpc_in->query))
+		return false;
+
+	cmds = rpc_in->query.n_commands;
+	if (cmds) {
+		int cmds_size = rpc_in->payload_size - sizeof(rpc_in->query);
+
+		if (cmds != cmds_size / sizeof(struct cxl_command_info))
+			return false;
+	}
+
+	return true;
+}
+
 static bool cxlctl_validate_rpc(struct fwctl_uctx *uctx,
 				struct fwctl_rpc_cxl *rpc_in,
 				enum fwctl_rpc_scope scope)
@@ -142,10 +160,17 @@  static bool cxlctl_validate_rpc(struct fwctl_uctx *uctx,
 	struct cxlctl_dev *cxlctl =
 		container_of(uctx->fwctl, struct cxlctl_dev, fwctl);
 
-	if (rpc_in->rpc_cmd != FWCTL_CXL_SEND_COMMAND)
+	switch (rpc_in->rpc_cmd) {
+	case FWCTL_CXL_QUERY_COMMANDS:
+		return cxlctl_validate_query_commands(rpc_in);
+
+	case FWCTL_CXL_SEND_COMMAND:
+		return cxlctl_validate_hw_cmds(cxlctl->mbox,
+					       &rpc_in->send_cmd, scope);
+
+	default:
 		return false;
-
-	return cxlctl_validate_hw_cmds(cxlctl->mbox, &rpc_in->send_cmd, scope);
+	}
 }
 
 static void *send_cxl_command(struct cxl_mailbox *cxl_mbox,
@@ -175,10 +200,17 @@  static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
 	if (!cxlctl_validate_rpc(uctx, rpc_in, scope))
 		return ERR_PTR(-EPERM);
 
-	if (rpc_in->rpc_cmd == FWCTL_CXL_SEND_COMMAND)
+	switch (rpc_in->rpc_cmd) {
+	case FWCTL_CXL_QUERY_COMMANDS:
+		return cxl_query_cmd_from_fwctl(cxl_mbox, &rpc_in->query,
+						out_len);
+
+	case FWCTL_CXL_SEND_COMMAND:
 		return send_cxl_command(cxl_mbox, &rpc_in->send_cmd, out_len);
 
-	return ERR_PTR(-EOPNOTSUPP);
+	default:
+		return ERR_PTR(-EOPNOTSUPP);
+	}
 }
 
 static const struct fwctl_ops cxlctl_ops = {
diff --git a/include/linux/cxl/mailbox.h b/include/linux/cxl/mailbox.h
index b3c74f3da9a5..13b5bb6e5bc3 100644
--- a/include/linux/cxl/mailbox.h
+++ b/include/linux/cxl/mailbox.h
@@ -168,5 +168,8 @@  int cxl_fwctl_send_cmd(struct cxl_mailbox *cxl_mbox,
 		       struct fwctl_cxl_command *fwctl_cmd,
 		       struct cxl_mbox_cmd *mbox_cmd,
 		       size_t *out_len);
+void *cxl_query_cmd_from_fwctl(struct cxl_mailbox *cxl_mbox,
+			       struct cxl_mem_query_commands *q,
+			       size_t *out_len);
 
 #endif
diff --git a/include/uapi/fwctl/cxl.h b/include/uapi/fwctl/cxl.h
index de8949a28473..a439f497b889 100644
--- a/include/uapi/fwctl/cxl.h
+++ b/include/uapi/fwctl/cxl.h
@@ -77,7 +77,10 @@  struct fwctl_rpc_cxl {
 	__u32 payload_size;
 	__u32 version;
 	__u32 rsvd;
-	struct fwctl_cxl_command send_cmd;
+	union {
+		struct cxl_mem_query_commands query;
+		struct fwctl_cxl_command send_cmd;
+	};
 };
 
 struct fwctl_rpc_cxl_out {