FreeBSD/Linux Kernel Cross Reference
sys/dev/xen/bus/xenpv.c

     /*
      * Copyright (c) 2014 Roger Pau Monné <roger.pau@citrix.com>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/pcpu.h>
    #include <sys/rman.h>
    #include <sys/smp.h>
    #include <sys/limits.h>
    #include <sys/vmmeter.h>
    
    #include <vm/vm.h>
    #include <vm/vm_page.h>
    #include <vm/vm_param.h>
    #include <vm/vm_phys.h>
    
    #include <xen/xen-os.h>
    #include <xen/gnttab.h>
    
    #include "xenmem_if.h"
    
    /*
     * Allocate unused physical memory above 4GB in order to map memory
     * from foreign domains. We use memory starting at 4GB in order to
     * prevent clashes with MMIO/ACPI regions.
     *
     * Since this is not possible on i386 just use any available memory
     * chunk above 1MB and hope we don't clash with anything else.
     *
     * Other architectures better document MMIO regions and drivers more
     * reliably reserve them.  As such, allow using any unpopulated memory
     * region.
     */
    #ifdef __amd64__
    #define LOW_MEM_LIMIT   0x100000000ul
    #elif defined(__i386__)
    #define LOW_MEM_LIMIT   0x100000ul
    #else
    #define LOW_MEM_LIMIT   0
    #endif
    
    static void
    xenpv_identify(driver_t *driver, device_t parent)
    {
            if (!xen_domain())
                    return;
    
            /* Make sure there's only one xenpv device. */
            if (devclass_get_device(devclass_find(driver->name), 0))
                    return;
    
            /*
             * The xenpv bus should be the last to attach in order
             * to properly detect if an ISA bus has already been added.
             */
            if (BUS_ADD_CHILD(parent, UINT_MAX, driver->name, 0) == NULL)
                    panic("Unable to attach xenpv bus.");
    }
    
    static int
    xenpv_probe(device_t dev)
    {
    
            device_set_desc(dev, "Xen PV bus");
            return (BUS_PROBE_NOWILDCARD);
    }
    
    static int
    xenpv_attach(device_t dev)
    {
           int error;
   
           /*
            * Let our child drivers identify any child devices that they
            * can find.  Once that is done attach any devices that we
            * found.
            */
           error = bus_generic_probe(dev);
           if (error)
                   return (error);
   
           error = bus_generic_attach(dev);
   
           return (error);
   }
   
   static struct resource *
   xenpv_alloc_physmem(device_t dev, device_t child, int *res_id, size_t size)
   {
           struct resource *res;
           vm_paddr_t phys_addr;
           void *virt_addr;
           int error;
   
           res = bus_alloc_resource(child, SYS_RES_MEMORY, res_id, LOW_MEM_LIMIT,
               ~0, size, RF_ACTIVE | RF_UNMAPPED);
           if (res == NULL)
                   return (NULL);
   
           phys_addr = rman_get_start(res);
           error = vm_phys_fictitious_reg_range(phys_addr, phys_addr + size,
               VM_MEMATTR_XEN);
           if (error) {
                   bus_release_resource(child, SYS_RES_MEMORY, *res_id, res);
                   return (NULL);
           }
           virt_addr = pmap_mapdev_attr(phys_addr, size, VM_MEMATTR_XEN);
           KASSERT(virt_addr != NULL, ("Failed to create linear mappings"));
           rman_set_virtual(res, virt_addr);
   
           return (res);
   }
   
   static int
   xenpv_free_physmem(device_t dev, device_t child, int res_id, struct resource *res)
   {
           vm_paddr_t phys_addr;
           void *virt_addr;
           size_t size;
   
           phys_addr = rman_get_start(res);
           size = rman_get_size(res);
           virt_addr = rman_get_virtual(res);
   
           pmap_unmapdev(virt_addr, size);
           vm_phys_fictitious_unreg_range(phys_addr, phys_addr + size);
           return (bus_release_resource(child, SYS_RES_MEMORY, res_id, res));
   }
   
   static device_method_t xenpv_methods[] = {
           /* Device interface */
           DEVMETHOD(device_identify,              xenpv_identify),
           DEVMETHOD(device_probe,                 xenpv_probe),
           DEVMETHOD(device_attach,                xenpv_attach),
           DEVMETHOD(device_suspend,               bus_generic_suspend),
           DEVMETHOD(device_resume,                bus_generic_resume),
   
           /* Bus interface */
           DEVMETHOD(bus_add_child,                bus_generic_add_child),
           DEVMETHOD(bus_alloc_resource,           bus_generic_alloc_resource),
           DEVMETHOD(bus_release_resource,         bus_generic_release_resource),
           DEVMETHOD(bus_activate_resource,        bus_generic_activate_resource),
           DEVMETHOD(bus_deactivate_resource,      bus_generic_deactivate_resource),
   
           /* Interface to allocate memory for foreign mappings */
           DEVMETHOD(xenmem_alloc,                 xenpv_alloc_physmem),
           DEVMETHOD(xenmem_free,                  xenpv_free_physmem),
   
           DEVMETHOD_END
   };
   
   static driver_t xenpv_driver = {
           "xenpv",
           xenpv_methods,
           0,
   };
   
   DRIVER_MODULE(xenpv, nexus, xenpv_driver, 0, 0);
   
   struct resource *
   xenmem_alloc(device_t dev, int *res_id, size_t size)
   {
           device_t parent;
   
           parent = device_get_parent(dev);
           if (parent == NULL)
                   return (NULL);
           return (XENMEM_ALLOC(parent, dev, res_id, size));
   }
   
   int
   xenmem_free(device_t dev, int res_id, struct resource *res)
   {
           device_t parent;
   
           parent = device_get_parent(dev);
           if (parent == NULL)
                   return (ENXIO);
           return (XENMEM_FREE(parent, dev, res_id, res));
   }

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