mfn_t __get_gfn_type_access(struct p2m_domain *p2m, unsigned long gfn,
p2m_type_t *t, p2m_access_t *a, p2m_query_t q,
unsigned int *page_order, bool_t locked)
{
mfn_t mfn;
/* Unshare makes no sense withuot populate. */
if ( q & P2M_UNSHARE )
q |= P2M_ALLOC;
if ( !p2m || !paging_mode_translate(p2m->domain) )
{
/* Not necessarily true, but for non-translated guests, we claim
* it's the most generic kind of memory */
*t = p2m_ram_rw;
return _mfn(gfn);
}
if ( locked )
/* Grab the lock here, don't release until put_gfn */
gfn_lock(p2m, gfn, 0);
mfn = p2m->get_entry(p2m, gfn, t, a, q, page_order);
if ( (q & P2M_UNSHARE) && p2m_is_shared(*t) )
{
ASSERT(!p2m_is_nestedp2m(p2m));
/* Try to unshare. If we fail, communicate ENOMEM without
* sleeping. */
if ( mem_sharing_unshare_page(p2m->domain, gfn, 0) < 0 )
(void)mem_sharing_notify_enomem(p2m->domain, gfn, 0);
mfn = p2m->get_entry(p2m, gfn, t, a, q, page_order);
}
if (unlikely((p2m_is_broken(*t))))
{
/* Return invalid_mfn to avoid caller's access */
mfn = _mfn(INVALID_MFN);
if ( q & P2M_ALLOC )
domain_crash(p2m->domain);
}
return mfn;
}
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;
}
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;
}
int
guest_physmap_add_entry(struct domain *d, unsigned long gfn,
unsigned long mfn, unsigned int page_order,
p2m_type_t t)
{
struct p2m_domain *p2m = p2m_get_hostp2m(d);
unsigned long i, ogfn;
p2m_type_t ot;
p2m_access_t a;
mfn_t omfn;
int pod_count = 0;
int rc = 0;
if ( !paging_mode_translate(d) )
{
if ( need_iommu(d) && t == p2m_ram_rw )
{
for ( i = 0; i < (1 << page_order); i++ )
{
rc = iommu_map_page(
d, mfn + i, mfn + i, IOMMUF_readable|IOMMUF_writable);
if ( rc != 0 )
{
while ( i-- > 0 )
iommu_unmap_page(d, mfn + i);
return rc;
}
}
}
return 0;
}
p2m_lock(p2m);
P2M_DEBUG("adding gfn=%#lx mfn=%#lx\n", gfn, mfn);
/* First, remove m->p mappings for existing p->m mappings */
for ( i = 0; i < (1UL << page_order); i++ )
{
omfn = p2m->get_entry(p2m, gfn + i, &ot, &a, 0, NULL);
if ( p2m_is_shared(ot) )
{
/* Do an unshare to cleanly take care of all corner
* cases. */
int rc;
rc = mem_sharing_unshare_page(p2m->domain, gfn + i, 0);
if ( rc )
{
p2m_unlock(p2m);
/* NOTE: Should a guest domain bring this upon itself,
* there is not a whole lot we can do. We are buried
* deep in locks from most code paths by now. So, fail
* the call and don't try to sleep on a wait queue
* while placing the mem event.
*
* However, all current (changeset 3432abcf9380) code
* paths avoid this unsavoury situation. For now.
*
* Foreign domains are okay to place an event as they
* won't go to sleep. */
(void)mem_sharing_notify_enomem(p2m->domain, gfn + i, 0);
return rc;
}
omfn = p2m->get_entry(p2m, gfn + i, &ot, &a, 0, NULL);
ASSERT(!p2m_is_shared(ot));
}
if ( p2m_is_grant(ot) )
{
/* Really shouldn't be unmapping grant maps this way */
domain_crash(d);
p2m_unlock(p2m);
return -EINVAL;
}
else if ( p2m_is_ram(ot) && !p2m_is_paged(ot) )
{
ASSERT(mfn_valid(omfn));
set_gpfn_from_mfn(mfn_x(omfn), INVALID_M2P_ENTRY);
}
else if ( ot == p2m_populate_on_demand )
{
/* Count how man PoD entries we'll be replacing if successful */
pod_count++;
}
else if ( p2m_is_paging(ot) && (ot != p2m_ram_paging_out) )
{
/* We're plugging a hole in the physmap where a paged out page was */
atomic_dec(&d->paged_pages);
}
}
/* Then, look for m->p mappings for this range and deal with them */
for ( i = 0; i < (1UL << page_order); i++ )
{
if ( page_get_owner(mfn_to_page(_mfn(mfn + i))) == dom_cow )
{
/* This is no way to add a shared page to your physmap! */
gdprintk(XENLOG_ERR, "Adding shared mfn %lx directly to dom %hu "
"physmap not allowed.\n", mfn+i, d->domain_id);
p2m_unlock(p2m);
return -EINVAL;
}
if ( page_get_owner(mfn_to_page(_mfn(mfn + i))) != d )
continue;
ogfn = mfn_to_gfn(d, _mfn(mfn+i));
if ( (ogfn != INVALID_M2P_ENTRY) && (ogfn != gfn + i) )
{
/* This machine frame is already mapped at another physical
* address */
P2M_DEBUG("aliased! mfn=%#lx, old gfn=%#lx, new gfn=%#lx\n",
mfn + i, ogfn, gfn + i);
omfn = p2m->get_entry(p2m, ogfn, &ot, &a, 0, NULL);
if ( p2m_is_ram(ot) && !p2m_is_paged(ot) )
{
ASSERT(mfn_valid(omfn));
P2M_DEBUG("old gfn=%#lx -> mfn %#lx\n",
ogfn , mfn_x(omfn));
if ( mfn_x(omfn) == (mfn + i) )
p2m_remove_page(p2m, ogfn, mfn + i, 0);
}
}
}
/* Now, actually do the two-way mapping */
if ( mfn_valid(_mfn(mfn)) )
{
if ( !set_p2m_entry(p2m, gfn, _mfn(mfn), page_order, t, p2m->default_access) )
{
rc = -EINVAL;
goto out; /* Failed to update p2m, bail without updating m2p. */
}
if ( !p2m_is_grant(t) )
{
for ( i = 0; i < (1UL << page_order); i++ )
set_gpfn_from_mfn(mfn+i, gfn+i);
}
}
else
{
gdprintk(XENLOG_WARNING, "Adding bad mfn to p2m map (%#lx -> %#lx)\n",
gfn, mfn);
if ( !set_p2m_entry(p2m, gfn, _mfn(INVALID_MFN), page_order,
p2m_invalid, p2m->default_access) )
rc = -EINVAL;
else
{
pod_lock(p2m);
p2m->pod.entry_count -= pod_count;
BUG_ON(p2m->pod.entry_count < 0);
pod_unlock(p2m);
}
}
out:
p2m_unlock(p2m);
return rc;
}
