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x86/xen: export xen_alloc_p2m_entry()

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Rename alloc_p2m() to xen_alloc_p2m_entry() and export it.

This is useful for ensuring that a p2m entry is allocated (i.e., not a
shared missing or identity entry) so that subsequent set_phys_to_machine()
calls will require no further allocations.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
v3:
- Make xen_alloc_p2m_entry() a nop on auto-xlate guests.
This commit is contained in:
David Vrabel 2015-07-22 14:48:09 +01:00
parent 1cf6a6c829
commit 8edfcf882e
2 changed files with 15 additions and 6 deletions
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2
arch/x86/include/asm/xen/page.h
View File

@ -43,6 +43,8 @@ extern unsigned long *xen_p2m_addr;
extern unsigned long xen_p2m_size;
extern unsigned long xen_max_p2m_pfn;
extern int xen_alloc_p2m_entry(unsigned long pfn);
extern unsigned long get_phys_to_machine(unsigned long pfn);
extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);

19
arch/x86/xen/p2m.c
View File

@ -530,7 +530,7 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
* the new pages are installed with cmpxchg; if we lose the race then
* simply free the page we allocated and use the one that's there.
*/
static bool alloc_p2m(unsigned long pfn)
int xen_alloc_p2m_entry(unsigned long pfn)
{
unsigned topidx;
unsigned long *top_mfn_p, *mid_mfn;
@ -540,6 +540,9 @@ static bool alloc_p2m(unsigned long pfn)
unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
unsigned long p2m_pfn;
if (xen_feature(XENFEAT_auto_translated_physmap))
return 0;
ptep = lookup_address(addr, &level);
BUG_ON(!ptep || level != PG_LEVEL_4K);
pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
@ -548,7 +551,7 @@ static bool alloc_p2m(unsigned long pfn)
/* PMD level is missing, allocate a new one */
ptep = alloc_p2m_pmd(addr, pte_pg);
if (!ptep)
return false;
return -ENOMEM;
}
if (p2m_top_mfn && pfn < MAX_P2M_PFN) {
@ -566,7 +569,7 @@ static bool alloc_p2m(unsigned long pfn)
mid_mfn = alloc_p2m_page();
if (!mid_mfn)
return false;
return -ENOMEM;
p2m_mid_mfn_init(mid_mfn, p2m_missing);
@ -592,7 +595,7 @@ static bool alloc_p2m(unsigned long pfn)
p2m = alloc_p2m_page();
if (!p2m)
return false;
return -ENOMEM;
if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
p2m_init(p2m);
@ -625,8 +628,9 @@ static bool alloc_p2m(unsigned long pfn)
HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
}
return true;
return 0;
}
EXPORT_SYMBOL(xen_alloc_p2m_entry);
unsigned long __init set_phys_range_identity(unsigned long pfn_s,
unsigned long pfn_e)
@ -688,7 +692,10 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
if (!alloc_p2m(pfn))
int ret;
ret = xen_alloc_p2m_entry(pfn);
if (ret < 0)
return false;
return __set_phys_to_machine(pfn, mfn);