Example #1
0
static void enable_hypercall_page(void)
{
    struct domain *d = current->domain;
    unsigned long gmfn = d->arch.hvm_domain.viridian.hypercall_gpa.fields.pfn;
    unsigned long mfn = gmfn_to_mfn(d, gmfn);
    uint8_t *p;

    if ( !mfn_valid(mfn) ||
         !get_page_and_type(mfn_to_page(mfn), d, PGT_writable_page) )
    {
        gdprintk(XENLOG_WARNING, "Bad GMFN %lx (MFN %lx)\n", gmfn, mfn);
        return;
    }

    p = map_domain_page(mfn);

    /*
     * We set the bit 31 in %eax (reserved field in the Viridian hypercall
     * calling convention) to differentiate Xen and Viridian hypercalls.
     */
    *(u8  *)(p + 0) = 0x0d; /* orl $0x80000000, %eax */
    *(u32 *)(p + 1) = 0x80000000;
    *(u8  *)(p + 5) = 0x0f; /* vmcall/vmmcall */
    *(u8  *)(p + 6) = 0x01;
    *(u8  *)(p + 7) = ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
                       ? 0xc1 : 0xd9);
    *(u8  *)(p + 8) = 0xc3; /* ret */
    memset(p + 9, 0xcc, PAGE_SIZE - 9); /* int3, int3, ... */

    unmap_domain_page(p);

    put_page_and_type(mfn_to_page(mfn));
}
Example #2
0
int guest_remove_page(struct domain *d, unsigned long gmfn)
{
    struct page_info *page;
    unsigned long mfn;

    mfn = gmfn_to_mfn(d, gmfn);
    if ( unlikely(!mfn_valid(mfn)) )
    {
        gdprintk(XENLOG_INFO, "Domain %u page number %lx invalid\n",
                d->domain_id, gmfn);
        return 0;
    }
            
    page = mfn_to_page(mfn);
    if ( unlikely(!get_page(page, d)) )
    {
        gdprintk(XENLOG_INFO, "Bad page free for domain %u\n", d->domain_id);
        return 0;
    }

    if ( test_and_clear_bit(_PGT_pinned, &page->u.inuse.type_info) )
        put_page_and_type(page);
            
    if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
        put_page(page);

    guest_physmap_remove_page(d, gmfn, mfn, 0);

    put_page(page);

    return 1;
}
Example #3
0
int guest_remove_page(struct domain *d, unsigned long gmfn)
{
    struct page_info *page;
#ifdef CONFIG_X86
    p2m_type_t p2mt;
#endif
    unsigned long mfn;

#ifdef CONFIG_X86
    mfn = mfn_x(gfn_to_mfn(p2m_get_hostp2m(d), gmfn, &p2mt)); 
    if ( unlikely(p2m_is_paging(p2mt)) )
    {
        guest_physmap_remove_page(d, gmfn, mfn, 0);
        p2m_mem_paging_drop_page(p2m_get_hostp2m(d), gmfn);
        return 1;
    }
#else
    mfn = gmfn_to_mfn(d, gmfn);
#endif
    if ( unlikely(!mfn_valid(mfn)) )
    {
        gdprintk(XENLOG_INFO, "Domain %u page number %lx invalid\n",
                d->domain_id, gmfn);
        return 0;
    }
            
    page = mfn_to_page(mfn);
#ifdef CONFIG_X86
    /* If gmfn is shared, just drop the guest reference (which may or may not
     * free the page) */
    if(p2m_is_shared(p2mt))
    {
        put_page_and_type(page);
        guest_physmap_remove_page(d, gmfn, mfn, 0);
        return 1;
    }

#endif /* CONFIG_X86 */
    if ( unlikely(!get_page(page, d)) )
    {
        gdprintk(XENLOG_INFO, "Bad page free for domain %u\n", d->domain_id);
        return 0;
    }

    if ( test_and_clear_bit(_PGT_pinned, &page->u.inuse.type_info) )
        put_page_and_type(page);
            
    if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
        put_page(page);

    guest_physmap_remove_page(d, gmfn, mfn, 0);

    put_page(page);

    return 1;
}
Example #4
0
File: memory.c Project: blue236/xen
int guest_remove_page(struct domain *d, unsigned long gmfn)
{
    struct page_info *page;
#ifdef CONFIG_X86
    p2m_type_t p2mt;
#endif
    unsigned long mfn;

#ifdef CONFIG_X86
    mfn = mfn_x(get_gfn_query(d, gmfn, &p2mt)); 
    if ( unlikely(p2m_is_paging(p2mt)) )
    {
        guest_physmap_remove_page(d, gmfn, mfn, 0);
        put_gfn(d, gmfn);
        /* If the page hasn't yet been paged out, there is an
         * actual page that needs to be released. */
        if ( p2mt == p2m_ram_paging_out )
        {
            ASSERT(mfn_valid(mfn));
            page = mfn_to_page(mfn);
            if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
                put_page(page);
        }
        p2m_mem_paging_drop_page(d, gmfn, p2mt);
        return 1;
    }
    if ( p2mt == p2m_mmio_direct )
    {
        clear_mmio_p2m_entry(d, gmfn, _mfn(mfn));
        put_gfn(d, gmfn);
        return 1;
    }
#else
    mfn = gmfn_to_mfn(d, gmfn);
#endif
    if ( unlikely(!mfn_valid(mfn)) )
    {
        put_gfn(d, gmfn);
        gdprintk(XENLOG_INFO, "Domain %u page number %lx invalid\n",
                d->domain_id, gmfn);
        return 0;
    }
            
#ifdef CONFIG_X86
    if ( p2m_is_shared(p2mt) )
    {
        /* Unshare the page, bail out on error. We unshare because 
         * we might be the only one using this shared page, and we
         * need to trigger proper cleanup. Once done, this is 
         * like any other page. */
        if ( mem_sharing_unshare_page(d, gmfn, 0) )
        {
            put_gfn(d, gmfn);
            (void)mem_sharing_notify_enomem(d, gmfn, 0);
            return 0;
        }
        /* Maybe the mfn changed */
        mfn = mfn_x(get_gfn_query_unlocked(d, gmfn, &p2mt));
        ASSERT(!p2m_is_shared(p2mt));
    }
#endif /* CONFIG_X86 */

    page = mfn_to_page(mfn);
    if ( unlikely(!get_page(page, d)) )
    {
        put_gfn(d, gmfn);
        gdprintk(XENLOG_INFO, "Bad page free for domain %u\n", d->domain_id);
        return 0;
    }

    if ( test_and_clear_bit(_PGT_pinned, &page->u.inuse.type_info) )
        put_page_and_type(page);

    /*
     * With the lack of an IOMMU on some platforms, domains with DMA-capable
     * device must retrieve the same pfn when the hypercall populate_physmap
     * is called.
     *
     * For this purpose (and to match populate_physmap() behavior), the page
     * is kept allocated.
     */
    if ( !is_domain_direct_mapped(d) &&
         test_and_clear_bit(_PGC_allocated, &page->count_info) )
        put_page(page);

    guest_physmap_remove_page(d, gmfn, mfn, 0);

    put_page(page);
    put_gfn(d, gmfn);

    return 1;
}
/*
 * Returns 0 if TLB flush / invalidate required by caller.
 * va will indicate the address to be invalidated.
 *
 * addr is _either_ a host virtual address, or the address of the pte to
 * update, as indicated by the GNTMAP_contains_pte flag.
 */
static void
__gnttab_map_grant_ref(
    struct gnttab_map_grant_ref *op)
{
    struct domain *ld, *rd;
    struct vcpu   *led;
    int            handle;
    unsigned long  frame = 0;
    int            rc = GNTST_okay;
    unsigned int   cache_flags;
    struct active_grant_entry *act;
    struct grant_mapping *mt;
    grant_entry_t *sha;
    union grant_combo scombo, prev_scombo, new_scombo;

    /*
     * We bound the number of times we retry CMPXCHG on memory locations that
     * we share with a guest OS. The reason is that the guest can modify that
     * location at a higher rate than we can read-modify-CMPXCHG, so the guest
     * could cause us to livelock. There are a few cases where it is valid for
     * the guest to race our updates (e.g., to change the GTF_readonly flag),
     * so we allow a few retries before failing.
     */
    int retries = 0;

    led = current;
    ld = led->domain;

    if ( unlikely((op->flags & (GNTMAP_device_map|GNTMAP_host_map)) == 0) )
    {
        gdprintk(XENLOG_INFO, "Bad flags in grant map op (%x).\n", op->flags);
        op->status = GNTST_bad_gntref;
        return;
    }

    if ( unlikely((rd = rcu_lock_domain_by_id(op->dom)) == NULL) )
    {
        gdprintk(XENLOG_INFO, "Could not find domain %d\n", op->dom);
        op->status = GNTST_bad_domain;
        return;
    }

    rc = xsm_grant_mapref(ld, rd, op->flags);
    if ( rc )
    {
        rcu_unlock_domain(rd);
        op->status = GNTST_permission_denied;
        return;
    }

    if ( unlikely((handle = get_maptrack_handle(ld->grant_table)) == -1) )
    {
        rcu_unlock_domain(rd);
        gdprintk(XENLOG_INFO, "Failed to obtain maptrack handle.\n");
        op->status = GNTST_no_device_space;
        return;
    }

    spin_lock(&rd->grant_table->lock);

    /* Bounds check on the grant ref */
    if ( unlikely(op->ref >= nr_grant_entries(rd->grant_table)))
        PIN_FAIL(unlock_out, GNTST_bad_gntref, "Bad ref (%d).\n", op->ref);

    act = &active_entry(rd->grant_table, op->ref);
    sha = &shared_entry(rd->grant_table, op->ref);

    /* If already pinned, check the active domid and avoid refcnt overflow. */
    if ( act->pin &&
            ((act->domid != ld->domain_id) ||
             (act->pin & 0x80808080U) != 0) )
        PIN_FAIL(unlock_out, GNTST_general_error,
                 "Bad domain (%d != %d), or risk of counter overflow %08x\n",
                 act->domid, ld->domain_id, act->pin);

    if ( !act->pin ||
            (!(op->flags & GNTMAP_readonly) &&
             !(act->pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask))) )
    {
        scombo.word = *(u32 *)&sha->flags;

        /*
         * This loop attempts to set the access (reading/writing) flags
         * in the grant table entry.  It tries a cmpxchg on the field
         * up to five times, and then fails under the assumption that
         * the guest is misbehaving.
         */
        for ( ; ; )
        {
            /* If not already pinned, check the grant domid and type. */
            if ( !act->pin &&
                    (((scombo.shorts.flags & GTF_type_mask) !=
                      GTF_permit_access) ||
                     (scombo.shorts.domid != ld->domain_id)) )
                PIN_FAIL(unlock_out, GNTST_general_error,
                         "Bad flags (%x) or dom (%d). (expected dom %d)\n",
                         scombo.shorts.flags, scombo.shorts.domid,
                         ld->domain_id);

            new_scombo = scombo;
            new_scombo.shorts.flags |= GTF_reading;

            if ( !(op->flags & GNTMAP_readonly) )
            {
                new_scombo.shorts.flags |= GTF_writing;
                if ( unlikely(scombo.shorts.flags & GTF_readonly) )
                    PIN_FAIL(unlock_out, GNTST_general_error,
                             "Attempt to write-pin a r/o grant entry.\n");
            }

            prev_scombo.word = cmpxchg((u32 *)&sha->flags,
                                       scombo.word, new_scombo.word);
            if ( likely(prev_scombo.word == scombo.word) )
                break;

            if ( retries++ == 4 )
                PIN_FAIL(unlock_out, GNTST_general_error,
                         "Shared grant entry is unstable.\n");

            scombo = prev_scombo;
        }

        if ( !act->pin )
        {
            act->domid = scombo.shorts.domid;
            act->frame = gmfn_to_mfn(rd, sha->frame);
        }
    }

    if ( op->flags & GNTMAP_device_map )
        act->pin += (op->flags & GNTMAP_readonly) ?
                    GNTPIN_devr_inc : GNTPIN_devw_inc;
    if ( op->flags & GNTMAP_host_map )
        act->pin += (op->flags & GNTMAP_readonly) ?
                    GNTPIN_hstr_inc : GNTPIN_hstw_inc;

    frame = act->frame;

    cache_flags = (sha->flags & (GTF_PAT | GTF_PWT | GTF_PCD) );

    spin_unlock(&rd->grant_table->lock);

    if ( is_iomem_page(frame) )
    {
        if ( !iomem_access_permitted(rd, frame, frame) )
        {
            gdprintk(XENLOG_WARNING,
                     "Iomem mapping not permitted %lx (domain %d)\n",
                     frame, rd->domain_id);
            rc = GNTST_general_error;
            goto undo_out;
        }

        rc = create_grant_host_mapping(
                 op->host_addr, frame, op->flags, cache_flags);
        if ( rc != GNTST_okay )
            goto undo_out;
    }
    else
    {
        if ( unlikely(!mfn_valid(frame)) ||
                unlikely(!(gnttab_host_mapping_get_page_type(op, ld, rd) ?
                           get_page_and_type(mfn_to_page(frame), rd,
                                             PGT_writable_page) :
                           get_page(mfn_to_page(frame), rd))) )
        {
            if ( !rd->is_dying )
                gdprintk(XENLOG_WARNING, "Could not pin grant frame %lx\n",
                         frame);
            rc = GNTST_general_error;
            goto undo_out;
        }

        if ( op->flags & GNTMAP_host_map )
        {
            rc = create_grant_host_mapping(op->host_addr, frame, op->flags, 0);
            if ( rc != GNTST_okay )
            {
                if ( gnttab_host_mapping_get_page_type(op, ld, rd) )
                    put_page_type(mfn_to_page(frame));
                put_page(mfn_to_page(frame));
                goto undo_out;
            }

            if ( op->flags & GNTMAP_device_map )
            {
                (void)get_page(mfn_to_page(frame), rd);
                if ( !(op->flags & GNTMAP_readonly) )
                    get_page_type(mfn_to_page(frame), PGT_writable_page);
            }
        }
    }

    TRACE_1D(TRC_MEM_PAGE_GRANT_MAP, op->dom);

    mt = &maptrack_entry(ld->grant_table, handle);
    mt->domid = op->dom;
    mt->ref   = op->ref;
    mt->flags = op->flags;

    op->dev_bus_addr = (u64)frame << PAGE_SHIFT;
    op->handle       = handle;
    op->status       = GNTST_okay;

    rcu_unlock_domain(rd);
    return;

undo_out:
    spin_lock(&rd->grant_table->lock);

    act = &active_entry(rd->grant_table, op->ref);
    sha = &shared_entry(rd->grant_table, op->ref);

    if ( op->flags & GNTMAP_device_map )
        act->pin -= (op->flags & GNTMAP_readonly) ?
                    GNTPIN_devr_inc : GNTPIN_devw_inc;
    if ( op->flags & GNTMAP_host_map )
        act->pin -= (op->flags & GNTMAP_readonly) ?
                    GNTPIN_hstr_inc : GNTPIN_hstw_inc;

    if ( !(op->flags & GNTMAP_readonly) &&
            !(act->pin & (GNTPIN_hstw_mask|GNTPIN_devw_mask)) )
        gnttab_clear_flag(_GTF_writing, &sha->flags);

    if ( !act->pin )
        gnttab_clear_flag(_GTF_reading, &sha->flags);

unlock_out:
    spin_unlock(&rd->grant_table->lock);
    op->status = rc;
    put_maptrack_handle(ld->grant_table, handle);
    rcu_unlock_domain(rd);
}
Example #6
0
int guest_remove_page(struct domain *d, unsigned long gmfn)
{
    struct page_info *page;
#ifdef CONFIG_X86
    p2m_type_t p2mt;
#endif
    unsigned long mfn;

#ifdef CONFIG_X86
    mfn = mfn_x(get_gfn_query(d, gmfn, &p2mt)); 
    if ( unlikely(p2m_is_paging(p2mt)) )
    {
        guest_physmap_remove_page(d, gmfn, mfn, 0);
        put_gfn(d, gmfn);
        /* If the page hasn't yet been paged out, there is an
         * actual page that needs to be released. */
        if ( p2mt == p2m_ram_paging_out )
        {
            ASSERT(mfn_valid(mfn));
            page = mfn_to_page(mfn);
            if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
                put_page(page);
        }
        p2m_mem_paging_drop_page(d, gmfn, p2mt);
        return 1;
    }
#else
    mfn = gmfn_to_mfn(d, gmfn);
#endif
    if ( unlikely(!mfn_valid(mfn)) )
    {
        put_gfn(d, gmfn);
        gdprintk(XENLOG_INFO, "Domain %u page number %lx invalid\n",
                d->domain_id, gmfn);
        return 0;
    }
            
#ifdef CONFIG_X86_64
    if ( p2m_is_shared(p2mt) )
    {
        /* Unshare the page, bail out on error. We unshare because 
         * we might be the only one using this shared page, and we
         * need to trigger proper cleanup. Once done, this is 
         * like any other page. */
        if ( mem_sharing_unshare_page(d, gmfn, 0) )
        {
            put_gfn(d, gmfn);
            (void)mem_sharing_notify_enomem(d, gmfn, 0);
            return 0;
        }
        /* Maybe the mfn changed */
        mfn = mfn_x(get_gfn_query_unlocked(d, gmfn, &p2mt));
        ASSERT(!p2m_is_shared(p2mt));
    }
#endif /* CONFIG_X86_64 */

    page = mfn_to_page(mfn);
    if ( unlikely(!get_page(page, d)) )
    {
        put_gfn(d, gmfn);
        gdprintk(XENLOG_INFO, "Bad page free for domain %u\n", d->domain_id);
        return 0;
    }

    if ( test_and_clear_bit(_PGT_pinned, &page->u.inuse.type_info) )
        put_page_and_type(page);
            
    if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
        put_page(page);

    guest_physmap_remove_page(d, gmfn, mfn, 0);

    put_page(page);
    put_gfn(d, gmfn);

    return 1;
}