paging.c

xen虚拟机源代码安装包

        d->arch.paging.log_dirty.dirty_count++;
    }

 out:
    log_dirty_unlock(d);
}

/* Read a domain's log-dirty bitmap and stats.  If the operation is a CLEAN,
 * clear the bitmap and stats as well. */
int paging_log_dirty_op(struct domain *d, struct xen_domctl_shadow_op *sc)
{
    int rv = 0, clean = 0, peek = 1;
    unsigned long pages = 0;
    mfn_t *l4, *l3, *l2;
    unsigned long *l1;
    int i4, i3, i2;

    domain_pause(d);
    log_dirty_lock(d);

    clean = (sc->op == XEN_DOMCTL_SHADOW_OP_CLEAN);

    PAGING_DEBUG(LOGDIRTY, "log-dirty %s: dom %u faults=%u dirty=%u\n",
                 (clean) ? "clean" : "peek",
                 d->domain_id,
                 d->arch.paging.log_dirty.fault_count,
                 d->arch.paging.log_dirty.dirty_count);

    sc->stats.fault_count = d->arch.paging.log_dirty.fault_count;
    sc->stats.dirty_count = d->arch.paging.log_dirty.dirty_count;

    if ( clean )
    {
        d->arch.paging.log_dirty.fault_count = 0;
        d->arch.paging.log_dirty.dirty_count = 0;
    }

    if ( guest_handle_is_null(sc->dirty_bitmap) )
        /* caller may have wanted just to clean the state or access stats. */
        peek = 0;

    if ( (peek || clean) && !mfn_valid(d->arch.paging.log_dirty.top) )
    {
        rv = -EINVAL; /* perhaps should be ENOMEM? */
        goto out;
    }

    if ( unlikely(d->arch.paging.log_dirty.failed_allocs) ) {
        printk("%s: %d failed page allocs while logging dirty pages\n",
               __FUNCTION__, d->arch.paging.log_dirty.failed_allocs);
        rv = -ENOMEM;
        goto out;
    }

    pages = 0;
    l4 = map_domain_page(mfn_x(d->arch.paging.log_dirty.top));

    for ( i4 = 0;
          (pages < sc->pages) && (i4 < LOGDIRTY_NODE_ENTRIES);
          i4++ )
    {
        l3 = mfn_valid(l4[i4]) ? map_domain_page(mfn_x(l4[i4])) : NULL;
        for ( i3 = 0;
              (pages < sc->pages) && (i3 < LOGDIRTY_NODE_ENTRIES);
              i3++ )
        {
            l2 = ((l3 && mfn_valid(l3[i3])) ?
                  map_domain_page(mfn_x(l3[i3])) : NULL);
            for ( i2 = 0;
                  (pages < sc->pages) && (i2 < LOGDIRTY_NODE_ENTRIES);
                  i2++ )
            {
                static unsigned long zeroes[PAGE_SIZE/BYTES_PER_LONG];
                unsigned int bytes = PAGE_SIZE;
                l1 = ((l2 && mfn_valid(l2[i2])) ?
                      map_domain_page(mfn_x(l2[i2])) : zeroes);
                if ( unlikely(((sc->pages - pages + 7) >> 3) < bytes) )
                    bytes = (unsigned int)((sc->pages - pages + 7) >> 3);
                if ( likely(peek) )
                {
                    if ( copy_to_guest_offset(sc->dirty_bitmap, pages >> 3,
                                              (uint8_t *)l1, bytes) != 0 )
                    {
                        rv = -EFAULT;
                        goto out;
                    }
                }
                if ( clean && l1 != zeroes )
                    clear_page(l1);
                pages += bytes << 3;
                if ( l1 != zeroes )
                    unmap_domain_page(l1);
            }
            if ( l2 )
                unmap_domain_page(l2);
        }
        if ( l3 )
            unmap_domain_page(l3);
    }
    unmap_domain_page(l4);

    if ( pages < sc->pages )
        sc->pages = pages;

    log_dirty_unlock(d);

    if ( clean )
    {
        /* We need to further call clean_dirty_bitmap() functions of specific
         * paging modes (shadow or hap).  Safe because the domain is paused. */
        d->arch.paging.log_dirty.clean_dirty_bitmap(d);
    }
    domain_unpause(d);
    return rv;

 out:
    log_dirty_unlock(d);
    domain_unpause(d);
    return rv;
}


/* Note that this function takes three function pointers. Callers must supply
 * these functions for log dirty code to call. This function usually is
 * invoked when paging is enabled. Check shadow_enable() and hap_enable() for
 * reference.
 *
 * These function pointers must not be followed with the log-dirty lock held.
 */
void paging_log_dirty_init(struct domain *d,
                           int    (*enable_log_dirty)(struct domain *d),
                           int    (*disable_log_dirty)(struct domain *d),
                           void   (*clean_dirty_bitmap)(struct domain *d))
{
    /* We initialize log dirty lock first */
    log_dirty_lock_init(d);

    d->arch.paging.log_dirty.enable_log_dirty = enable_log_dirty;
    d->arch.paging.log_dirty.disable_log_dirty = disable_log_dirty;
    d->arch.paging.log_dirty.clean_dirty_bitmap = clean_dirty_bitmap;
    d->arch.paging.log_dirty.top = _mfn(INVALID_MFN);
}

/* This function fress log dirty bitmap resources. */
void paging_log_dirty_teardown(struct domain*d)
{
    log_dirty_lock(d);
    paging_free_log_dirty_bitmap(d);
    log_dirty_unlock(d);
}
/************************************************/
/*           CODE FOR PAGING SUPPORT            */
/************************************************/
/* Domain paging struct initialization. */
int paging_domain_init(struct domain *d)
{
    int rc;

    if ( (rc = p2m_init(d)) != 0 )
        return rc;

    /* The order of the *_init calls below is important, as the later
     * ones may rewrite some common fields.  Shadow pagetables are the
     * default... */
    shadow_domain_init(d);

    /* ... but we will use hardware assistance if it's available. */
    if ( hap_enabled(d) )
        hap_domain_init(d);

    return 0;
}

/* vcpu paging struct initialization goes here */
void paging_vcpu_init(struct vcpu *v)
{
    if ( hap_enabled(v->domain) )
        hap_vcpu_init(v);
    else
        shadow_vcpu_init(v);
}


int paging_domctl(struct domain *d, xen_domctl_shadow_op_t *sc,
                  XEN_GUEST_HANDLE(void) u_domctl)
{
    int rc;

    if ( unlikely(d == current->domain) )
    {
        gdprintk(XENLOG_INFO, "Tried to do a paging op on itself.\n");
        return -EINVAL;
    }

    if ( unlikely(d->is_dying) )
    {
        gdprintk(XENLOG_INFO, "Ignoring paging op on dying domain %u\n",
                 d->domain_id);
        return 0;
    }

    if ( unlikely(d->vcpu[0] == NULL) )
    {
        PAGING_ERROR("Paging op on a domain (%u) with no vcpus\n",
                     d->domain_id);
        return -EINVAL;
    }

    rc = xsm_shadow_control(d, sc->op);
    if ( rc )
        return rc;

    /* Code to handle log-dirty. Note that some log dirty operations
     * piggy-back on shadow operations. For example, when
     * XEN_DOMCTL_SHADOW_OP_OFF is called, it first checks whether log dirty
     * mode is enabled. If does, we disables log dirty and continues with
     * shadow code. For this reason, we need to further dispatch domctl
     * to next-level paging code (shadow or hap).
     */
    switch ( sc->op )
    {
    case XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY:
        return paging_log_dirty_enable(d);

    case XEN_DOMCTL_SHADOW_OP_ENABLE:
        if ( sc->mode & XEN_DOMCTL_SHADOW_ENABLE_LOG_DIRTY )
            return paging_log_dirty_enable(d);

    case XEN_DOMCTL_SHADOW_OP_OFF:
        if ( paging_mode_log_dirty(d) )
            if ( (rc = paging_log_dirty_disable(d)) != 0 )
                return rc;

    case XEN_DOMCTL_SHADOW_OP_CLEAN:
    case XEN_DOMCTL_SHADOW_OP_PEEK:
        return paging_log_dirty_op(d, sc);
    }

    /* Here, dispatch domctl to the appropriate paging code */
    if ( hap_enabled(d) )
        return hap_domctl(d, sc, u_domctl);
    else
        return shadow_domctl(d, sc, u_domctl);
}

/* Call when destroying a domain */
void paging_teardown(struct domain *d)
{
    if ( hap_enabled(d) )
        hap_teardown(d);
    else
        shadow_teardown(d);

    /* clean up log dirty resources. */
    paging_log_dirty_teardown(d);
}

/* Call once all of the references to the domain have gone away */
void paging_final_teardown(struct domain *d)
{
    if ( hap_enabled(d) )
        hap_final_teardown(d);
    else
        shadow_final_teardown(d);

    p2m_final_teardown(d);
}

/* Enable an arbitrary paging-assistance mode.  Call once at domain
 * creation. */
int paging_enable(struct domain *d, u32 mode)
{
    if ( hap_enabled(d) )
        return hap_enable(d, mode | PG_HAP_enable);
    else
        return shadow_enable(d, mode | PG_SH_enable);
}

/* Print paging-assistance info to the console */
void paging_dump_domain_info(struct domain *d)
{
    if ( paging_mode_enabled(d) )
    {
        printk("    paging assistance: ");
        if ( paging_mode_shadow(d) )
            printk("shadow ");
        if ( paging_mode_hap(d) )
            printk("hap ");
        if ( paging_mode_refcounts(d) )
            printk("refcounts ");
        if ( paging_mode_log_dirty(d) )
            printk("log_dirty ");
        if ( paging_mode_translate(d) )
            printk("translate ");
        if ( paging_mode_external(d) )
            printk("external ");
        printk("\n");
    }
}

void paging_dump_vcpu_info(struct vcpu *v)
{
    if ( paging_mode_enabled(v->domain) )
    {
        printk("    paging assistance: ");
        if ( paging_mode_shadow(v->domain) )
        {
            if ( v->arch.paging.mode )
                printk("shadowed %u-on-%u\n",
                       v->arch.paging.mode->guest_levels,
                       v->arch.paging.mode->shadow.shadow_levels);
            else
                printk("not shadowed\n");
        }
        else if ( paging_mode_hap(v->domain) && v->arch.paging.mode )
            printk("hap, %u levels\n",
                   v->arch.paging.mode->guest_levels);
        else
            printk("none\n");
    }
}


/*
 * Local variables:
 * mode: C
 * c-set-style: "BSD"
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 */