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authorJeremy Fitzhardinge <jeremy@goop.org>2008-05-26 23:31:19 +0100
committerThomas Gleixner <tglx@linutronix.de>2008-05-27 10:11:37 +0200
commit8006ec3e911f93d702e1d4a4e387e244ab434924 (patch)
tree87c4a8648ff2f559ce039bf606fa40e033c48b3c /arch/x86/xen
parentd451bb7aa852627bdf7be7937dc3d9d9f261b235 (diff)
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: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/Kconfig10
-rw-r--r--arch/x86/xen/mmu.c25
-rw-r--r--arch/x86/xen/setup.c3
3 files changed, 25 insertions, 13 deletions
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 525b108411b..d0f1c7c5dc3 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -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
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index c3b27dec6f0..644232aa7bf 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -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 */
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 37f8f0b8f74..488447878a9 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -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);