Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8006ec3e authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Thomas Gleixner
Browse files

xen: add configurable max domain size 



Add a config option to set the max size of a Xen domain.  This is used
to scale the size of the physical-to-machine array; it ends up using
around 1 page/GByte, so there's no reason to be very restrictive.

For a 32-bit guest, the default value of 8GB is probably sufficient;
there's not much point in giving a 32-bit machine much more memory
than that.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent d451bb7a

arch/x86/xen/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -11,3 +11,13 @@ config XEN 
	  This is the Linux Xen port.  Enabling this will allow the

	  kernel to boot in a paravirtualized environment under the

	  Xen hypervisor.



config XEN_MAX_DOMAIN_MEMORY

       int "Maximum allowed size of a domain in gigabytes"

       default 8

       depends on XEN

       help

         The pseudo-physical to machine address array is sized

         according to the maximum possible memory size of a Xen

         domain.  This array uses 1 page per gigabyte, so there's no

         need to be too stingy here.
 
 No newline at end of file

arch/x86/xen/mmu.c

+12 −13
Original line number Diff line number Diff line
@@ -56,19 +56,13 @@ 
#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 unsigned long *p2m_top[MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE];



static inline unsigned p2m_top_index(unsigned long pfn)

{

	BUG_ON(pfn >= MAX_GUEST_PAGES);

	BUG_ON(pfn >= MAX_DOMAIN_PAGES);

	return pfn / P2M_ENTRIES_PER_PAGE;

}
@@ -81,12 +75,9 @@ void __init xen_build_dynamic_phys_to_machine(void) 
{

	unsigned pfn;

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

	unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);



	BUG_ON(xen_start_info->nr_pages >= MAX_GUEST_PAGES);



	for(pfn = 0;

	    pfn < xen_start_info->nr_pages;

	    pfn += P2M_ENTRIES_PER_PAGE) {

	for(pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {

		unsigned topidx = p2m_top_index(pfn);



		p2m_top[topidx] = &mfn_list[pfn];
@@ -97,6 +88,9 @@ unsigned long get_phys_to_machine(unsigned long pfn) 
{

	unsigned topidx, idx;



	if (unlikely(pfn >= MAX_DOMAIN_PAGES))

		return INVALID_P2M_ENTRY;



	topidx = p2m_top_index(pfn);

	if (p2m_top[topidx] == NULL)

		return INVALID_P2M_ENTRY;
@@ -129,6 +123,11 @@ void set_phys_to_machine(unsigned long pfn, unsigned long mfn) 
		return;

	}



	if (unlikely(pfn >= MAX_DOMAIN_PAGES)) {

		BUG_ON(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 */

arch/x86/xen/setup.c

+3 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <asm/xen/hypervisor.h>

#include <asm/xen/hypercall.h>



#include <xen/page.h>

#include <xen/interface/callback.h>

#include <xen/interface/physdev.h>

#include <xen/features.h>
@@ -36,6 +37,8 @@ char * __init xen_memory_setup(void) 
{

	unsigned long max_pfn = xen_start_info->nr_pages;



	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);



	e820.nr_map = 0;

	add_memory_region(0, LOWMEMSIZE(), E820_RAM);

	add_memory_region(HIGH_MEMORY, PFN_PHYS(max_pfn)-HIGH_MEMORY, E820_RAM);

include/asm-x86/xen/page.h

+5 −0
Original line number Diff line number Diff line
@@ -26,6 +26,11 @@ typedef struct xpaddr { 
#define FOREIGN_FRAME_BIT	(1UL<<31)

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



/* Maximum amount of memory we can handle in a domain in pages */

#define MAX_DOMAIN_PAGES						\

    ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))





extern unsigned long get_phys_to_machine(unsigned long pfn);

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