int
set_shared_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
{
struct p2m_domain *p2m = p2m_get_hostp2m(d);
int rc = 0;
p2m_access_t a;
p2m_type_t ot;
mfn_t omfn;
unsigned long pg_type;
if ( !paging_mode_translate(p2m->domain) )
return 0;
gfn_lock(p2m, gfn, 0);
omfn = p2m->get_entry(p2m, gfn, &ot, &a, 0, NULL);
/* At the moment we only allow p2m change if gfn has already been made
* sharable first */
ASSERT(p2m_is_shared(ot));
ASSERT(mfn_valid(omfn));
/* Set the m2p entry to invalid only if there are no further type
* refs to this page as shared */
pg_type = read_atomic(&(mfn_to_page(omfn)->u.inuse.type_info));
if ( (pg_type & PGT_count_mask) == 0
|| (pg_type & PGT_type_mask) != PGT_shared_page )
set_gpfn_from_mfn(mfn_x(omfn), INVALID_M2P_ENTRY);
P2M_DEBUG("set shared %lx %lx\n", gfn, mfn_x(mfn));
rc = set_p2m_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2m_ram_shared, p2m->default_access);
gfn_unlock(p2m, gfn, 0);
if ( 0 == rc )
gdprintk(XENLOG_ERR,
"set_shared_p2m_entry: set_p2m_entry failed! mfn=%08lx\n",
mfn_x(get_gfn_query_unlocked(p2m->domain, gfn, &ot)));
return rc;
}
static always_inline spinlock_tickets_t observe_lock(spinlock_tickets_t *t)
{
spinlock_tickets_t v;
smp_rmb();
v.head_tail = read_atomic(&t->head_tail);
return v;
}
long read_console_ring(struct xen_sysctl_readconsole *op)
{
XEN_GUEST_HANDLE_PARAM(char) str;
uint32_t idx, len, max, sofar, c, p;
str = guest_handle_cast(op->buffer, char),
max = op->count;
sofar = 0;
c = read_atomic(&conringc);
p = read_atomic(&conringp);
if ( op->incremental &&
(c <= p ? c < op->index && op->index <= p
: c < op->index || op->index <= p) )
c = op->index;
while ( (c != p) && (sofar < max) )
{
idx = CONRING_IDX_MASK(c);
len = p - c;
if ( (idx + len) > conring_size )
len = conring_size - idx;
if ( (sofar + len) > max )
len = max - sofar;
if ( copy_to_guest_offset(str, sofar, &conring[idx], len) )
return -EFAULT;
sofar += len;
c += len;
}
if ( op->clear )
{
spin_lock_irq(&console_lock);
conringc = p - c > conring_size ? p - conring_size : c;
spin_unlock_irq(&console_lock);
}
op->count = sofar;
op->index = c;
return 0;
}
static always_inline u16 observe_head(spinlock_tickets_t *t)
{
smp_rmb();
return read_atomic(&t->head);
}