Commit 8edfcf88 authored by David Vrabel's avatar David Vrabel
Browse files

x86/xen: export xen_alloc_p2m_entry() 



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: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: default avatarDaniel Kiper <daniel.kiper@oracle.com>
---
v3:
- Make xen_alloc_p2m_entry() a nop on auto-xlate guests.
parent 1cf6a6c8

arch/x86/include/asm/xen/page.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/xen/p2m.c

+13 −6
Original line number Diff line number Diff line
@@ -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);

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