unsigned long __init set_phys_range_identity(unsigned long pfn_s,
unsigned long pfn_e)
{
unsigned long pfn;
if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN))
return 0;
if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
return pfn_e - pfn_s;
if (pfn_s > pfn_e)
return 0;
for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1));
pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE));
pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE)
{
WARN_ON(!early_alloc_p2m(pfn));
}
early_alloc_p2m_middle(pfn_s, true);
early_alloc_p2m_middle(pfn_e, true);
for (pfn = pfn_s; pfn < pfn_e; pfn++)
if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn)))
break;
if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s),
"Identity mapping failed. We are %ld short of 1-1 mappings!\n",
(pfn_e - pfn_s) - (pfn - pfn_s)))
printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn);
return pfn - pfn_s;
}
bool __init early_set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
if (!early_alloc_p2m(pfn))
return false;
if (!early_alloc_p2m_middle(pfn, false /* boundary crossover OK!*/))
return false;
if (!__set_phys_to_machine(pfn, mfn))
return false;
}
return true;
}
/*
* Skim over the P2M tree looking at pages that are either filled with
* INVALID_P2M_ENTRY or with 1:1 PFNs. If found, re-use that page and
* replace the P2M leaf with a p2m_missing or p2m_identity.
* Stick the old page in the new P2M tree location.
*/
bool __init early_can_reuse_p2m_middle(unsigned long set_pfn, unsigned long set_mfn)
{
unsigned topidx;
unsigned mididx;
unsigned ident_pfns;
unsigned inv_pfns;
unsigned long *p2m;
unsigned long *mid_mfn_p;
unsigned idx;
unsigned long pfn;
/* We only look when this entails a P2M middle layer */
if (p2m_index(set_pfn))
return false;
for (pfn = 0; pfn <= MAX_DOMAIN_PAGES; pfn += P2M_PER_PAGE) {
topidx = p2m_top_index(pfn);
if (!p2m_top[topidx])
continue;
if (p2m_top[topidx] == p2m_mid_missing)
continue;
mididx = p2m_mid_index(pfn);
p2m = p2m_top[topidx][mididx];
if (!p2m)
continue;
if ((p2m == p2m_missing) || (p2m == p2m_identity))
continue;
if ((unsigned long)p2m == INVALID_P2M_ENTRY)
continue;
ident_pfns = 0;
inv_pfns = 0;
for (idx = 0; idx < P2M_PER_PAGE; idx++) {
/* IDENTITY_PFNs are 1:1 */
if (p2m[idx] == IDENTITY_FRAME(pfn + idx))
ident_pfns++;
else if (p2m[idx] == INVALID_P2M_ENTRY)
inv_pfns++;
else
break;
}
if ((ident_pfns == P2M_PER_PAGE) || (inv_pfns == P2M_PER_PAGE))
goto found;
}
return false;
found:
/* Found one, replace old with p2m_identity or p2m_missing */
p2m_top[topidx][mididx] = (ident_pfns ? p2m_identity : p2m_missing);
/* And the other for save/restore.. */
mid_mfn_p = p2m_top_mfn_p[topidx];
/* NOTE: Even if it is a p2m_identity it should still be point to
* a page filled with INVALID_P2M_ENTRY entries. */
mid_mfn_p[mididx] = virt_to_mfn(p2m_missing);
/* Reset where we want to stick the old page in. */
topidx = p2m_top_index(set_pfn);
mididx = p2m_mid_index(set_pfn);
/* This shouldn't happen */
if (WARN_ON(p2m_top[topidx] == p2m_mid_missing))
early_alloc_p2m(set_pfn);
if (WARN_ON(p2m_top[topidx][mididx] != p2m_missing))
return false;
p2m_init(p2m);
p2m_top[topidx][mididx] = p2m;
mid_mfn_p = p2m_top_mfn_p[topidx];
mid_mfn_p[mididx] = virt_to_mfn(p2m);
return true;
}
