pci-arbiter: Implement memory mapping over region files

* pci-arbiter/Makefile:
	* Add device_map.c to sources
* pci-arbiter/device_map.c:
* pci-arbiter/device_map.h:
	* New module for device mapping
	* Relies on libpciaccess mapping methods
* pci-arbiter/func_files.c:
	* io_region_file(): Use the new device mapping module
* pci-arbiter/netfs_impl.c:
	* Implements netfs_get_filemap():
		* Uses the device mapping module to map the region to the
		  arbiter space
		* Calls the kernel RPC vm_region_create_proxy() to obtain the
		  memory object proxy
		* Only region files are mapped for now
Message-Id: <20211219112647.11512-4-jlledom@mailfence.com>

5 files changed, 124 insertions, 12 deletions

diff --git a/pci-arbiter/Makefile b/pci-arbiter/Makefile
index d3d205ec..821c3ca9 100644
--- a/pci-arbiter/Makefile
+++ b/pci-arbiter/Makefile
@@ -22,7 +22,7 @@ PORTDIR = $(srcdir)/port
 
 SRCS		= main.c pci-ops.c netfs_impl.c \
 		  pcifs.c ncache.c options.c func_files.c \
-		  pciServer.c startup_notifyServer.c
+		  device_map.c pciServer.c startup_notifyServer.c
 OBJS		= $(SRCS:.c=.o) $(MIGSTUBS)
 
 HURDLIBS= fshelp ports shouldbeinlibc netfs iohelp ihash trivfs machdev
diff --git a/pci-arbiter/device_map.c b/pci-arbiter/device_map.c
new file mode 100644
index 00000000..216adfb9
--- /dev/null
+++ b/pci-arbiter/device_map.c
@@ -0,0 +1,38 @@
+/*
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* Implementation for device memory mapping functions */
+
+#include <pciaccess.h>
+
+#include "device_map.h"
+
+error_t
+device_map_region (struct pci_device *device, struct pci_mem_region *region)
+{
+  error_t err = 0;
+
+  if (region->memory == 0)
+    {
+      err = pci_device_map_range (device, region->base_addr, region->size,
+				  PCI_DEV_MAP_FLAG_WRITABLE, &region->memory);
+    }
+
+  return err;
+}
diff --git a/pci-arbiter/device_map.h b/pci-arbiter/device_map.h
new file mode 100644
index 00000000..9062e901
--- /dev/null
+++ b/pci-arbiter/device_map.h
@@ -0,0 +1,32 @@
+/*
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* Header for device memory mapping functions */
+
+#ifndef DEVICE_MAP_H
+#define DEVICE_MAP_H
+
+#include <hurd.h>
+
+#include <pciaccess.h>
+
+error_t device_map_region (struct pci_device *device,
+			   struct pci_mem_region *region);
+
+#endif /* DEVICE_MAP_H */
diff --git a/pci-arbiter/func_files.c b/pci-arbiter/func_files.c
index d7d8c5d5..81ebfded 100644
--- a/pci-arbiter/func_files.c
+++ b/pci-arbiter/func_files.c
@@ -30,6 +30,8 @@
 
 #include <pciaccess.h>
 
+#include "device_map.h"
+
 /* Read or write a block of data from/to the configuration space */
 static error_t
 config_block_op (struct pci_device *dev, off_t offset, size_t * len,
@@ -202,16 +204,10 @@ io_region_file (struct pcifs_dirent * e, off_t offset, size_t * len,
     region_block_ioport_op (region->base_addr, offset, len, data, read);
   else
     {
-      /* First check whether the region is already mapped */
-      if (region->memory == 0)
-	{
-	  /* Not mapped, try to map it now */
-	  err =
-	    pci_device_map_range (e->device, region->base_addr, region->size,
-				  PCI_DEV_MAP_FLAG_WRITABLE, &region->memory);
-	  if (err)
-	    return err;
-	}
+      /* Ensure the region is mapped */
+      err = device_map_region (e->device, region);
+      if (err)
+	return err;
       if (read)
 	memcpy (data, region->memory + offset, *len);
       else
diff --git a/pci-arbiter/netfs_impl.c b/pci-arbiter/netfs_impl.c
index 2087cfb4..8b4bd22b 100644
--- a/pci-arbiter/netfs_impl.c
+++ b/pci-arbiter/netfs_impl.c
@@ -29,11 +29,16 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <hurd/netfs.h>
+#include <hurd/paths.h>
+#include <mach/mach4.h>
+#include <device/device.h>
+
+#include <pciaccess.h>
 
 #include "pcifs.h"
 #include "ncache.h"
-#include <pciaccess.h>
 #include "func_files.h"
+#include "device_map.h"
 
 #define DIRENTS_CHUNK_SIZE      (8*1024)
 /* Returned directory entries are aligned to blocks this many bytes long.
@@ -563,3 +568,44 @@ netfs_node_norefs (struct node *node)
 {
   destroy_node (node);
 }
+
+mach_port_t
+netfs_get_filemap (struct node *node, vm_prot_t prot)
+{
+  error_t err;
+  memory_object_t proxy;
+  vm_prot_t max_prot;
+  size_t reg_num;
+  struct pci_mem_region *region;
+
+  /* Only regions files can be mapped */
+  if (strncmp
+      (node->nn->ln->name, FILE_REGION_NAME, strlen (FILE_REGION_NAME)))
+    {
+      goto error;
+    }
+
+  /* Get region info */
+  reg_num =
+    strtol (&node->nn->ln->name[strlen (node->nn->ln->name) - 1], 0, 16);
+  region = &node->nn->ln->device->regions[reg_num];
+
+  /* Ensure the region is mapped */
+  err = device_map_region (node->nn->ln->device, region);
+  if (err)
+    return err;
+
+  /* Create a new memory object proxy with the required protection */
+  max_prot = (VM_PROT_READ | VM_PROT_WRITE) & prot;
+  err =
+    vm_region_create_proxy(mach_task_self (), (vm_address_t)region->memory,
+			    max_prot, region->size, &proxy);
+  if (err)
+    goto error;
+
+  return proxy;
+
+error:
+  errno = EOPNOTSUPP;
+  return MACH_PORT_NULL;
+}