lk/kernel/vm/vmm.c

/*
 * Copyright (c) 2014 Travis Geiselbrecht
 *
 * Use of this source code is governed by a MIT-style
 * license that can be found in the LICENSE file or at
 * https://opensource.org/licenses/MIT
 */
#include <assert.h>
#include <kernel/mutex.h>
#include <kernel/vm.h>
#include <lk/console_cmd.h>
#include <lk/err.h>
#include <lk/trace.h>
#include <string.h>
#include "vm_priv.h"

#define LOCAL_TRACE 0

static struct list_node aspace_list = LIST_INITIAL_VALUE(aspace_list);
static mutex_t vmm_lock = MUTEX_INITIAL_VALUE(vmm_lock);

vmm_aspace_t _kernel_aspace;

static void dump_aspace(const vmm_aspace_t *a);
static void dump_region(const vmm_region_t *r);

void vmm_init_preheap(void) {
    /* initialize the kernel address space */
    strlcpy(_kernel_aspace.name, "kernel", sizeof(_kernel_aspace.name));
    _kernel_aspace.base = KERNEL_ASPACE_BASE;
    _kernel_aspace.size = KERNEL_ASPACE_SIZE;
    _kernel_aspace.flags = VMM_ASPACE_FLAG_KERNEL;
    list_initialize(&_kernel_aspace.region_list);

    arch_mmu_init_aspace(&_kernel_aspace.arch_aspace, KERNEL_ASPACE_BASE, KERNEL_ASPACE_SIZE, ARCH_ASPACE_FLAG_KERNEL);

    list_add_head(&aspace_list, &_kernel_aspace.node);
}

void vmm_init(void) {
}

static inline bool is_inside_aspace(const vmm_aspace_t *aspace, vaddr_t vaddr) {
    return (vaddr >= aspace->base && vaddr <= aspace->base + aspace->size - 1);
}

static bool is_region_inside_aspace(const vmm_aspace_t *aspace, vaddr_t vaddr, size_t size) {
    /* is the starting address within the address space*/
    if (!is_inside_aspace(aspace, vaddr))
        return false;

    if (size == 0)
        return true;

    /* see if the size is enough to wrap the integer */
    if (vaddr + size - 1 < vaddr)
        return false;

    /* test to see if the end address is within the address space's */
    if (vaddr + size - 1 > aspace->base + aspace->size - 1)
        return false;

    return true;
}

static size_t trim_to_aspace(const vmm_aspace_t *aspace, vaddr_t vaddr, size_t size) {
    DEBUG_ASSERT(is_inside_aspace(aspace, vaddr));

    if (size == 0)
        return size;

    size_t offset = vaddr - aspace->base;

    //LTRACEF("vaddr 0x%lx size 0x%zx offset 0x%zx aspace base 0x%lx aspace size 0x%zx\n",
    //        vaddr, size, offset, aspace->base, aspace->size);

    if (offset + size < offset)
        size = ULONG_MAX - offset - 1;

    //LTRACEF("size now 0x%zx\n", size);

    if (offset + size >= aspace->size - 1)
        size = aspace->size - offset;

    //LTRACEF("size now 0x%zx\n", size);

    return size;
}

static vmm_region_t *alloc_region_struct(const char *name, vaddr_t base, size_t size,
        uint flags, uint arch_mmu_flags) {
    DEBUG_ASSERT(name);

    vmm_region_t *r = calloc(1, sizeof(vmm_region_t));
    if (!r)
        return NULL;

    strlcpy(r->name, name, sizeof(r->name));
    r->base = base;
    r->size = size;
    r->flags = flags;
    r->arch_mmu_flags = arch_mmu_flags;
    list_initialize(&r->page_list);

    return r;
}

/* add a region to the appropriate spot in the address space list,
 * testing to see if there's a space */
static status_t add_region_to_aspace(vmm_aspace_t *aspace, vmm_region_t *r) {
    DEBUG_ASSERT(aspace);
    DEBUG_ASSERT(r);

    LTRACEF("aspace %p base 0x%lx size 0x%zx r %p base 0x%lx size 0x%zx\n",
            aspace, aspace->base, aspace->size, r, r->base, r->size);

    /* only try if the region will at least fit in the address space */
    if (r->size == 0 || !is_region_inside_aspace(aspace, r->base, r->size)) {
        LTRACEF("region was out of range\n");
        return ERR_OUT_OF_RANGE;
    }

    vaddr_t r_end = r->base + r->size - 1;

    /* does it fit in front */
    vmm_region_t *last;
    last = list_peek_head_type(&aspace->region_list, vmm_region_t, node);
    if (!last || r_end < last->base) {
        /* empty list or not empty and fits before the first element */
        list_add_head(&aspace->region_list, &r->node);
        return NO_ERROR;
    }

    /* walk the list, finding the right spot to put it */
    list_for_every_entry(&aspace->region_list, last, vmm_region_t, node) {
        /* does it go after last? */
        if (r->base > last->base + last->size - 1) {
            /* get the next element in the list */
            vmm_region_t *next = list_next_type(&aspace->region_list, &last->node, vmm_region_t, node);
            if (!next || (r_end < next->base)) {
                /* end of the list or next exists and it goes between them */
                list_add_after(&last->node, &r->node);
                return NO_ERROR;
            }
        }
    }

    LTRACEF("couldn't find spot\n");
    return ERR_NO_MEMORY;
}

/*
 *  Try to pick the spot within specified gap
 *
 *  Arch can override this to impose it's own restrictions.
 */
__WEAK vaddr_t arch_mmu_pick_spot(arch_aspace_t *aspace, vaddr_t base, uint prev_region_arch_mmu_flags,
                                  vaddr_t end,  uint next_region_arch_mmu_flags,
                                  vaddr_t align, size_t size, uint arch_mmu_flags) {
    /* just align it by default */
    return ALIGN(base, align);
}

/*
 *  Returns true if the caller has to stop search
 */
static inline bool check_gap(vmm_aspace_t *aspace,
                             vmm_region_t *prev, vmm_region_t *next,
                             vaddr_t *pva, vaddr_t align, size_t size,
                             uint arch_mmu_flags) {
    vaddr_t gap_beg; /* first byte of a gap */
    vaddr_t gap_end; /* last byte of a gap */

    DEBUG_ASSERT(pva);

    if (prev)
        gap_beg = prev->base + prev->size;
    else
        gap_beg = aspace->base;

    if (next) {
        if (gap_beg == next->base)
            goto next_gap;  /* no gap between regions */
        gap_end = next->base - 1;
    } else {
        if (gap_beg == (aspace->base + aspace->size))
            goto not_found;  /* no gap at the end of address space. Stop search */
        gap_end = aspace->base + aspace->size - 1;
    }

    *pva = arch_mmu_pick_spot(&aspace->arch_aspace, gap_beg, prev ? prev->arch_mmu_flags : ARCH_MMU_FLAG_INVALID,
                              gap_end, next ? next->arch_mmu_flags : ARCH_MMU_FLAG_INVALID,
                              align, size, arch_mmu_flags);
    if (*pva < gap_beg)
        goto not_found; /* address wrapped around */

    if (*pva < gap_end && ((gap_end - *pva + 1) >= size)) {
        /* we have enough room */
        return true; /* found spot, stop search */
    }

next_gap:
    return false; /* continue search */

not_found:
    *pva = -1;
    return true; /* not_found: stop search */
}

static vaddr_t alloc_spot(vmm_aspace_t *aspace, size_t size, uint8_t align_pow2,
                          uint arch_mmu_flags, struct list_node **before) {
    DEBUG_ASSERT(aspace);
    DEBUG_ASSERT(size > 0 && IS_PAGE_ALIGNED(size));

    LTRACEF("aspace %p size 0x%zx align %hhu\n", aspace, size, align_pow2);

    if (align_pow2 < PAGE_SIZE_SHIFT)
        align_pow2 = PAGE_SIZE_SHIFT;
    vaddr_t align = 1UL << align_pow2;

    vaddr_t spot;
    vmm_region_t *r = NULL;

    /* try to pick spot at the beginning of address space */
    if (check_gap(aspace, NULL,
                  list_peek_head_type(&aspace->region_list, vmm_region_t, node),
                  &spot, align, size, arch_mmu_flags))
        goto done;

    /* search the middle of the list */
    list_for_every_entry(&aspace->region_list, r, vmm_region_t, node) {
        if (check_gap(aspace, r,
                      list_next_type(&aspace->region_list, &r->node, vmm_region_t, node),
                      &spot, align, size, arch_mmu_flags))
            goto done;
    }

    /* couldn't find anything */
    return -1;

done:
    if (before)
        *before = r ? &r->node : &aspace->region_list;
    return spot;
}

/* allocate a region structure and stick it in the address space */
static vmm_region_t *alloc_region(vmm_aspace_t *aspace, const char *name, size_t size,
                                  vaddr_t vaddr, uint8_t align_pow2,
                                  uint vmm_flags, uint region_flags, uint arch_mmu_flags) {
    /* make a region struct for it and stick it in the list */
    vmm_region_t *r = alloc_region_struct(name, vaddr, size, region_flags, arch_mmu_flags);
    if (!r)
        return NULL;

    /* if they ask us for a specific spot, put it there */
    if (vmm_flags & VMM_FLAG_VALLOC_SPECIFIC) {
        /* stick it in the list, checking to see if it fits */
        if (add_region_to_aspace(aspace, r) < 0) {
            /* didn't fit */
            free(r);
            return NULL;
        }
    } else {
        /* allocate a virtual slot for it */
        struct list_node *before = NULL;

        vaddr = alloc_spot(aspace, size, align_pow2, arch_mmu_flags, &before);
        LTRACEF("alloc_spot returns 0x%lx, before %p\n", vaddr, before);

        if (vaddr == (vaddr_t)-1) {
            LTRACEF("failed to find spot\n");
            free(r);
            return NULL;
        }

        DEBUG_ASSERT(before != NULL);

        r->base = (vaddr_t)vaddr;

        /* add it to the region list */
        list_add_after(before, &r->node);
    }

    return r;
}

status_t vmm_reserve_space(vmm_aspace_t *aspace, const char *name, size_t size, vaddr_t vaddr) {
    LTRACEF("aspace %p name '%s' size 0x%zx vaddr 0x%lx\n", aspace, name, size, vaddr);

    DEBUG_ASSERT(aspace);
    DEBUG_ASSERT(IS_PAGE_ALIGNED(vaddr));
    DEBUG_ASSERT(IS_PAGE_ALIGNED(size));

    if (!name)
        name = "";

    if (!aspace)
        return ERR_INVALID_ARGS;
    if (size == 0)
        return NO_ERROR;
    if (!IS_PAGE_ALIGNED(vaddr) || !IS_PAGE_ALIGNED(size))
        return ERR_INVALID_ARGS;

    if (!is_inside_aspace(aspace, vaddr))
        return ERR_OUT_OF_RANGE;

    /* trim the size */
    size = trim_to_aspace(aspace, vaddr, size);

    mutex_acquire(&vmm_lock);

    /* lookup how it's already mapped */
    uint arch_mmu_flags = 0;
    arch_mmu_query(&aspace->arch_aspace, vaddr, NULL, &arch_mmu_flags);

    /* build a new region structure */
    vmm_region_t *r = alloc_region(aspace, name, size, vaddr, 0,
                                   VMM_FLAG_VALLOC_SPECIFIC, VMM_REGION_FLAG_RESERVED, arch_mmu_flags);

    mutex_release(&vmm_lock);
    return r ? NO_ERROR : ERR_NO_MEMORY;
}

status_t vmm_alloc_physical(vmm_aspace_t *aspace, const char *name, size_t size,
                            void **ptr, uint8_t align_log2, paddr_t paddr, uint vmm_flags, uint arch_mmu_flags) {
    status_t ret;

    LTRACEF("aspace %p name '%s' size 0x%zx ptr %p paddr 0x%lx vmm_flags 0x%x arch_mmu_flags 0x%x\n",
            aspace, name, size, ptr ? *ptr : 0, paddr, vmm_flags, arch_mmu_flags);

    DEBUG_ASSERT(aspace);
    DEBUG_ASSERT(IS_PAGE_ALIGNED(paddr));
    DEBUG_ASSERT(IS_PAGE_ALIGNED(size));

    if (!name)
        name = "";

    if (!aspace)
        return ERR_INVALID_ARGS;
    if (size == 0)
        return NO_ERROR;
    if (!IS_PAGE_ALIGNED(paddr) || !IS_PAGE_ALIGNED(size))
        return ERR_INVALID_ARGS;

    vaddr_t vaddr = 0;

    /* if they're asking for a specific spot, copy the address */
    if (vmm_flags & VMM_FLAG_VALLOC_SPECIFIC) {
        /* can't ask for a specific spot and then not provide one */
        if (!ptr) {
            return ERR_INVALID_ARGS;
        }
        vaddr = (vaddr_t)*ptr;
    }

    mutex_acquire(&vmm_lock);

    /* allocate a region and put it in the aspace list */
    vmm_region_t *r = alloc_region(aspace, name, size, vaddr, align_log2, vmm_flags,
                                   VMM_REGION_FLAG_PHYSICAL, arch_mmu_flags);
    if (!r) {
        ret = ERR_NO_MEMORY;
        goto err_alloc_region;
    }

    /* return the vaddr if requested */
    if (ptr)
        *ptr = (void *)r->base;

    /* map all of the pages */
    int err = arch_mmu_map(&aspace->arch_aspace, r->base, paddr, size / PAGE_SIZE, arch_mmu_flags);
    LTRACEF("arch_mmu_map returns %d\n", err);

    ret = NO_ERROR;

err_alloc_region:
    mutex_release(&vmm_lock);
    return ret;
}

status_t vmm_alloc_contiguous(vmm_aspace_t *aspace, const char *name, size_t size, void **ptr,
                              uint8_t align_pow2, uint vmm_flags, uint arch_mmu_flags) {
    status_t err = NO_ERROR;

    LTRACEF("aspace %p name '%s' size 0x%zx ptr %p align %hhu vmm_flags 0x%x arch_mmu_flags 0x%x\n",
            aspace, name, size, ptr ? *ptr : 0, align_pow2, vmm_flags, arch_mmu_flags);

    DEBUG_ASSERT(aspace);

    size = ROUNDUP(size, PAGE_SIZE);
    if (size == 0)
        return ERR_INVALID_ARGS;

    if (!name)
        name = "";

    vaddr_t vaddr = 0;

    /* if they're asking for a specific spot, copy the address */
    if (vmm_flags & VMM_FLAG_VALLOC_SPECIFIC) {
        /* can't ask for a specific spot and then not provide one */
        if (!ptr) {
            err = ERR_INVALID_ARGS;
            goto err;
        }
        vaddr = (vaddr_t)*ptr;
    }

    /* allocate physical memory up front, in case it cant be satisfied */
    struct list_node page_list;
    list_initialize(&page_list);

    paddr_t pa = 0;
    /* allocate a run of physical pages */
    size_t count = pmm_alloc_contiguous(size / PAGE_SIZE, align_pow2, &pa, &page_list);
    if (count < size / PAGE_SIZE) {
        DEBUG_ASSERT(count == 0); /* check that the pmm didn't allocate a partial run */
        err = ERR_NO_MEMORY;
        goto err;
    }

    mutex_acquire(&vmm_lock);

    /* allocate a region and put it in the aspace list */
    vmm_region_t *r = alloc_region(aspace, name, size, vaddr, align_pow2, vmm_flags,
                                   VMM_REGION_FLAG_PHYSICAL, arch_mmu_flags);
    if (!r) {
        err = ERR_NO_MEMORY;
        goto err1;
    }

    /* return the vaddr if requested */
    if (ptr)
        *ptr = (void *)r->base;

    /* map all of the pages */
    arch_mmu_map(&aspace->arch_aspace, r->base, pa, size / PAGE_SIZE, arch_mmu_flags);
    // XXX deal with error mapping here

    vm_page_t *p;
    while ((p = list_remove_head_type(&page_list, vm_page_t, node))) {
        list_add_tail(&r->page_list, &p->node);
    }

    mutex_release(&vmm_lock);
    return NO_ERROR;

err1:
    mutex_release(&vmm_lock);
    pmm_free(&page_list);
err:
    return err;
}

status_t vmm_alloc(vmm_aspace_t *aspace, const char *name, size_t size, void **ptr,
                   uint8_t align_pow2, uint vmm_flags, uint arch_mmu_flags) {
    status_t err = NO_ERROR;

    LTRACEF("aspace %p name '%s' size 0x%zx ptr %p align %hhu vmm_flags 0x%x arch_mmu_flags 0x%x\n",
            aspace, name, size, ptr ? *ptr : 0, align_pow2, vmm_flags, arch_mmu_flags);

    DEBUG_ASSERT(aspace);

    size = ROUNDUP(size, PAGE_SIZE);
    if (size == 0)
        return ERR_INVALID_ARGS;

    if (!name)
        name = "";

    vaddr_t vaddr = 0;

    /* if they're asking for a specific spot, copy the address */
    if (vmm_flags & VMM_FLAG_VALLOC_SPECIFIC) {
        /* can't ask for a specific spot and then not provide one */
        if (!ptr) {
            err = ERR_INVALID_ARGS;
            goto err;
        }
        vaddr = (vaddr_t)*ptr;
    }

    /* allocate physical memory up front, in case it cant be satisfied */

    /* allocate a random pile of pages */
    struct list_node page_list;
    list_initialize(&page_list);

    size_t count = pmm_alloc_pages(size / PAGE_SIZE, &page_list);
    DEBUG_ASSERT(count <= size);
    if (count < size / PAGE_SIZE) {
        LTRACEF("failed to allocate enough pages (asked for %zu, got %zu)\n", size / PAGE_SIZE, count);
        pmm_free(&page_list);
        err = ERR_NO_MEMORY;
        goto err;
    }

    mutex_acquire(&vmm_lock);

    /* allocate a region and put it in the aspace list */
    vmm_region_t *r = alloc_region(aspace, name, size, vaddr, align_pow2, vmm_flags,
                                   VMM_REGION_FLAG_PHYSICAL, arch_mmu_flags);
    if (!r) {
        err = ERR_NO_MEMORY;
        goto err1;
    }

    /* return the vaddr if requested */
    if (ptr)
        *ptr = (void *)r->base;

    /* map all of the pages */
    /* XXX use smarter algorithm that tries to build runs */
    vm_page_t *p;
    vaddr_t va = r->base;
    DEBUG_ASSERT(IS_PAGE_ALIGNED(va));
    while ((p = list_remove_head_type(&page_list, vm_page_t, node))) {
        DEBUG_ASSERT(va <= r->base + r->size - 1);

        paddr_t pa = vm_page_to_paddr(p);
        DEBUG_ASSERT(IS_PAGE_ALIGNED(pa));

        arch_mmu_map(&aspace->arch_aspace, va, pa, 1, arch_mmu_flags);
        // XXX deal with error mapping here

        list_add_tail(&r->page_list, &p->node);

        va += PAGE_SIZE;
    }

    mutex_release(&vmm_lock);
    return NO_ERROR;

err1:
    mutex_release(&vmm_lock);
    pmm_free(&page_list);
err:
    return err;
}

static vmm_region_t *vmm_find_region(const vmm_aspace_t *aspace, vaddr_t vaddr) {
    vmm_region_t *r;

    DEBUG_ASSERT(aspace);

    if (!aspace)
        return NULL;

    /* search the region list */
    list_for_every_entry(&aspace->region_list, r, vmm_region_t, node) {
        if ((vaddr >= r->base) && (vaddr <= r->base + r->size - 1))
            return r;
    }

    return NULL;
}

status_t vmm_free_region(vmm_aspace_t *aspace, vaddr_t vaddr) {
    mutex_acquire(&vmm_lock);

    vmm_region_t *r = vmm_find_region (aspace, vaddr);
    if (!r) {
        mutex_release(&vmm_lock);
        return ERR_NOT_FOUND;
    }

    /* remove it from aspace */
    list_delete(&r->node);

    /* unmap it */
    arch_mmu_unmap(&aspace->arch_aspace, r->base, r->size / PAGE_SIZE);

    mutex_release(&vmm_lock);

    /* return physical pages if any */
    pmm_free(&r->page_list);

    /* free it */
    free(r);

    return NO_ERROR;
}

status_t vmm_create_aspace(vmm_aspace_t **_aspace, const char *name, uint flags) {
    status_t err;

    vmm_aspace_t *aspace = calloc(1, sizeof(vmm_aspace_t));
    if (!aspace)
        return ERR_NO_MEMORY;

    if (name)
        strlcpy(aspace->name, name, sizeof(aspace->name));
    else
        strlcpy(aspace->name, "unnamed", sizeof(aspace->name));

    aspace->flags = flags;

    if (aspace->flags & VMM_ASPACE_FLAG_KERNEL) {
        aspace->base = KERNEL_ASPACE_BASE;
        aspace->size = KERNEL_ASPACE_SIZE;
    } else {
        aspace->base = USER_ASPACE_BASE;
        aspace->size = USER_ASPACE_SIZE;
    }

    /* initialize the arch specific component to our address space */
    err = arch_mmu_init_aspace(&aspace->arch_aspace, aspace->base, aspace->size,
                               (aspace->flags & VMM_ASPACE_FLAG_KERNEL) ? ARCH_ASPACE_FLAG_KERNEL : 0);
    if (err < 0) {
        free(aspace);
        return err;
    }

    list_clear_node(&aspace->node);
    list_initialize(&aspace->region_list);

    mutex_acquire(&vmm_lock);
    list_add_head(&aspace_list, &aspace->node);
    mutex_release(&vmm_lock);

    *_aspace = aspace;

    return NO_ERROR;
}

status_t vmm_free_aspace(vmm_aspace_t *aspace) {
    /* pop it out of the global aspace list */
    mutex_acquire(&vmm_lock);
    if (!list_in_list(&aspace->node)) {
        mutex_release(&vmm_lock);
        return ERR_INVALID_ARGS;
    }
    list_delete(&aspace->node);

    /* free all of the regions */
    struct list_node region_list = LIST_INITIAL_VALUE(region_list);

    vmm_region_t *r;
    while ((r = list_remove_head_type(&aspace->region_list, vmm_region_t, node))) {
        /* add it to our tempoary list */
        list_add_tail(&region_list, &r->node);

        /* unmap it */
        arch_mmu_unmap(&aspace->arch_aspace, r->base, r->size / PAGE_SIZE);
    }
    mutex_release(&vmm_lock);

    /* without the vmm lock held, free all of the pmm pages and the structure */
    while ((r = list_remove_head_type(&region_list, vmm_region_t, node))) {
        /* return physical pages if any */
        pmm_free(&r->page_list);

        /* free it */
        free(r);
    }

    /* make sure the current thread does not map the aspace */
    thread_t *current_thread = get_current_thread();
    if (current_thread->aspace == aspace) {
        THREAD_LOCK(state);
        current_thread->aspace = NULL;
        vmm_context_switch(aspace, NULL);
        THREAD_UNLOCK(state);
    }

    /* destroy the arch portion of the aspace */
    arch_mmu_destroy_aspace(&aspace->arch_aspace);

    /* free the aspace */
    free(aspace);

    return NO_ERROR;
}

void vmm_context_switch(vmm_aspace_t *oldspace, vmm_aspace_t *newaspace) {
    DEBUG_ASSERT(thread_lock_held());

    arch_mmu_context_switch(newaspace ? &newaspace->arch_aspace : NULL);
}

void vmm_set_active_aspace(vmm_aspace_t *aspace) {
    LTRACEF("aspace %p\n", aspace);

    thread_t *t = get_current_thread();
    DEBUG_ASSERT(t);

    if (aspace == t->aspace)
        return;

    /* grab the thread lock and switch to the new address space */
    THREAD_LOCK(state);
    vmm_aspace_t *old = t->aspace;
    t->aspace = aspace;
    vmm_context_switch(old, t->aspace);
    THREAD_UNLOCK(state);
}

static void dump_region(const vmm_region_t *r) {
    printf("\tregion %p: name '%s' range 0x%lx - 0x%lx size 0x%zx flags 0x%x mmu_flags 0x%x\n",
           r, r->name, r->base, r->base + r->size - 1, r->size, r->flags, r->arch_mmu_flags);
}

static void dump_aspace(const vmm_aspace_t *a) {
    printf("aspace %p: name '%s' range 0x%lx - 0x%lx size 0x%zx flags 0x%x\n",
           a, a->name, a->base, a->base + a->size - 1, a->size, a->flags);

    printf("regions:\n");
    vmm_region_t *r;
    list_for_every_entry(&a->region_list, r, vmm_region_t, node) {
        dump_region(r);
    }
}

static int cmd_vmm(int argc, const cmd_args *argv) {
    if (argc < 2) {
notenoughargs:
        printf("not enough arguments\n");
usage:
        printf("usage:\n");
        printf("%s aspaces\n", argv[0].str);
        printf("%s alloc <size> <align_pow2>\n", argv[0].str);
        printf("%s alloc_physical <paddr> <size> <align_pow2>\n", argv[0].str);
        printf("%s alloc_contig <size> <align_pow2>\n", argv[0].str);
        printf("%s free_region <address>\n", argv[0].str);
        printf("%s create_aspace\n", argv[0].str);
        printf("%s create_test_aspace\n", argv[0].str);
        printf("%s free_aspace <address>\n", argv[0].str);
        printf("%s set_test_aspace <address>\n", argv[0].str);
        return ERR_GENERIC;
    }

    static vmm_aspace_t *test_aspace;
    if (!test_aspace)
        test_aspace = vmm_get_kernel_aspace();

    if (!strcmp(argv[1].str, "aspaces")) {
        vmm_aspace_t *a;
        list_for_every_entry(&aspace_list, a, vmm_aspace_t, node) {
            dump_aspace(a);
        }
    } else if (!strcmp(argv[1].str, "alloc")) {
        if (argc < 4) goto notenoughargs;

        void *ptr = (void *)0x99;
        status_t err = vmm_alloc(test_aspace, "alloc test", argv[2].u, &ptr, argv[3].u, 0, 0);
        printf("vmm_alloc returns %d, ptr %p\n", err, ptr);
    } else if (!strcmp(argv[1].str, "alloc_physical")) {
        if (argc < 4) goto notenoughargs;

        void *ptr = (void *)0x99;
        status_t err = vmm_alloc_physical(test_aspace, "physical test", argv[3].u, &ptr,
                                          argv[4].u, argv[2].u, 0, ARCH_MMU_FLAG_UNCACHED_DEVICE);
        printf("vmm_alloc_physical returns %d, ptr %p\n", err, ptr);
    } else if (!strcmp(argv[1].str, "alloc_contig")) {
        if (argc < 4) goto notenoughargs;

        void *ptr = (void *)0x99;
        status_t err = vmm_alloc_contiguous(test_aspace, "contig test", argv[2].u, &ptr, argv[3].u, 0, 0);
        printf("vmm_alloc_contig returns %d, ptr %p\n", err, ptr);
    } else if (!strcmp(argv[1].str, "free_region")) {
        if (argc < 2) goto notenoughargs;

        status_t err = vmm_free_region(test_aspace, (vaddr_t)argv[2].u);
        printf("vmm_free_region returns %d\n", err);
    } else if (!strcmp(argv[1].str, "create_aspace")) {
        vmm_aspace_t *aspace;
        status_t err = vmm_create_aspace(&aspace, "test", 0);
        printf("vmm_create_aspace returns %d, aspace %p\n", err, aspace);
    } else if (!strcmp(argv[1].str, "create_test_aspace")) {
        vmm_aspace_t *aspace;
        status_t err = vmm_create_aspace(&aspace, "test", 0);
        printf("vmm_create_aspace returns %d, aspace %p\n", err, aspace);
        if (err < 0)
            return err;

        test_aspace = aspace;
        get_current_thread()->aspace = aspace;
        thread_sleep(1); // XXX hack to force it to reschedule and thus load the aspace
    } else if (!strcmp(argv[1].str, "free_aspace")) {
        if (argc < 2) goto notenoughargs;

        vmm_aspace_t *aspace = (void *)argv[2].u;
        if (test_aspace == aspace)
            test_aspace = NULL;

        if (get_current_thread()->aspace == aspace) {
            get_current_thread()->aspace = NULL;
            thread_sleep(1); // hack
        }

        status_t err = vmm_free_aspace(aspace);
        printf("vmm_free_aspace returns %d\n", err);
    } else if (!strcmp(argv[1].str, "set_test_aspace")) {
        if (argc < 2) goto notenoughargs;

        test_aspace = (void *)argv[2].u;
        get_current_thread()->aspace = test_aspace;
        thread_sleep(1); // XXX hack to force it to reschedule and thus load the aspace
    } else {
        printf("unknown command\n");
        goto usage;
    }

    return NO_ERROR;
}

STATIC_COMMAND_START
#if LK_DEBUGLEVEL > 0
STATIC_COMMAND("vmm", "virtual memory manager", &cmd_vmm)
#endif
STATIC_COMMAND_END(vmm);