Commit d451bb7a authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Thomas Gleixner
Browse files

xen: make phys_to_machine structure dynamic 



We now support the use of memory hotplug, so the physical to machine
page mapping structure must be dynamic.  This is implemented as a
two-level radix tree structure, which allows us to efficiently
incrementally allocate memory for the p2m table as new pages are
added.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 955d6f17

arch/x86/xen/enlighten.c

+1 −1
Original line number Diff line number Diff line
@@ -1221,7 +1221,7 @@ asmlinkage void __init xen_start_kernel(void) 


	/* Get mfn list */

	if (!xen_feature(XENFEAT_auto_translated_physmap))

		phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list;

		xen_build_dynamic_phys_to_machine();



	pgd = (pgd_t *)xen_start_info->pt_base;

arch/x86/xen/mmu.c

+85 −0
Original line number Diff line number Diff line
@@ -56,6 +56,91 @@ 
#include "multicalls.h"

#include "mmu.h"



/*

 * This should probably be a config option.  On 32-bit, it costs 1

 * page/gig of memory; on 64-bit its 2 pages/gig.  If we want it to be

 * completely unbounded we can add another level to the p2m structure.

 */

#define MAX_GUEST_PAGES		(16ull * 1024*1024*1024 / PAGE_SIZE)

#define P2M_ENTRIES_PER_PAGE	(PAGE_SIZE / sizeof(unsigned long))



static unsigned long *p2m_top[MAX_GUEST_PAGES / P2M_ENTRIES_PER_PAGE];



static inline unsigned p2m_top_index(unsigned long pfn)

{

	BUG_ON(pfn >= MAX_GUEST_PAGES);

	return pfn / P2M_ENTRIES_PER_PAGE;

}



static inline unsigned p2m_index(unsigned long pfn)

{

	return pfn % P2M_ENTRIES_PER_PAGE;

}



void __init xen_build_dynamic_phys_to_machine(void)

{

	unsigned pfn;

	unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;



	BUG_ON(xen_start_info->nr_pages >= MAX_GUEST_PAGES);



	for(pfn = 0;

	    pfn < xen_start_info->nr_pages;

	    pfn += P2M_ENTRIES_PER_PAGE) {

		unsigned topidx = p2m_top_index(pfn);



		p2m_top[topidx] = &mfn_list[pfn];

	}

}



unsigned long get_phys_to_machine(unsigned long pfn)

{

	unsigned topidx, idx;



	topidx = p2m_top_index(pfn);

	if (p2m_top[topidx] == NULL)

		return INVALID_P2M_ENTRY;



	idx = p2m_index(pfn);

	return p2m_top[topidx][idx];

}



static void alloc_p2m(unsigned long **pp)

{

	unsigned long *p;

	unsigned i;



	p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);

	BUG_ON(p == NULL);



	for(i = 0; i < P2M_ENTRIES_PER_PAGE; i++)

		p[i] = INVALID_P2M_ENTRY;



	if (cmpxchg(pp, NULL, p) != NULL)

		free_page((unsigned long)p);

}



void set_phys_to_machine(unsigned long pfn, unsigned long mfn)

{

	unsigned topidx, idx;



	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {

		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);

		return;

	}



	topidx = p2m_top_index(pfn);

	if (p2m_top[topidx] == NULL) {

		/* no need to allocate a page to store an invalid entry */

		if (mfn == INVALID_P2M_ENTRY)

			return;

		alloc_p2m(&p2m_top[topidx]);

	}



	idx = p2m_index(pfn);

	p2m_top[topidx][idx] = mfn;

}



xmaddr_t arbitrary_virt_to_machine(unsigned long address)

{

	unsigned int level;

arch/x86/xen/setup.c

+0 −2
Original line number Diff line number Diff line
@@ -27,8 +27,6 @@ 
extern const char xen_hypervisor_callback[];

extern const char xen_failsafe_callback[];



unsigned long *phys_to_machine_mapping;

EXPORT_SYMBOL(phys_to_machine_mapping);



/**

 * machine_specific_memory_setup - Hook for machine specific memory setup.

arch/x86/xen/xen-ops.h

+2 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ void __init xen_arch_setup(void); 
void __init xen_init_IRQ(void);

void xen_enable_sysenter(void);



void __init xen_build_dynamic_phys_to_machine(void);



void xen_setup_timer(int cpu);

void xen_setup_cpu_clockevents(void);

unsigned long xen_cpu_khz(void);

include/asm-x86/xen/page.h

+6 −14
Original line number Diff line number Diff line
@@ -26,15 +26,15 @@ typedef struct xpaddr { 
#define FOREIGN_FRAME_BIT	(1UL<<31)

#define FOREIGN_FRAME(m)	((m) | FOREIGN_FRAME_BIT)



extern unsigned long *phys_to_machine_mapping;

extern unsigned long get_phys_to_machine(unsigned long pfn);

extern void set_phys_to_machine(unsigned long pfn, unsigned long mfn);



static inline unsigned long pfn_to_mfn(unsigned long pfn)

{

	if (xen_feature(XENFEAT_auto_translated_physmap))

		return pfn;



	return phys_to_machine_mapping[(unsigned int)(pfn)] &

		~FOREIGN_FRAME_BIT;

	return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT;

}



static inline int phys_to_machine_mapping_valid(unsigned long pfn)
@@ -42,7 +42,7 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn) 
	if (xen_feature(XENFEAT_auto_translated_physmap))

		return 1;



	return (phys_to_machine_mapping[pfn] != INVALID_P2M_ENTRY);

	return get_phys_to_machine(pfn) != INVALID_P2M_ENTRY;

}



static inline unsigned long mfn_to_pfn(unsigned long mfn)
@@ -106,20 +106,12 @@ static inline unsigned long mfn_to_local_pfn(unsigned long mfn) 
	unsigned long pfn = mfn_to_pfn(mfn);

	if ((pfn < max_mapnr)

	    && !xen_feature(XENFEAT_auto_translated_physmap)

	    && (phys_to_machine_mapping[pfn] != mfn))

	    && (get_phys_to_machine(pfn) != mfn))

		return max_mapnr; /* force !pfn_valid() */

	/* XXX fixme; not true with sparsemem */

	return pfn;

}



static inline void set_phys_to_machine(unsigned long pfn, unsigned long mfn)

{

	if (xen_feature(XENFEAT_auto_translated_physmap)) {

		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);

		return;

	}

	phys_to_machine_mapping[pfn] = mfn;

}



/* VIRT <-> MACHINE conversion */

#define virt_to_machine(v)	(phys_to_machine(XPADDR(__pa(v))))

#define virt_to_mfn(v)		(pfn_to_mfn(PFN_DOWN(__pa(v))))

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