xen: switch extra memory accounting to use pfns
Instead of using physical addresses for accounting of extra memory
areas available for ballooning switch to pfns as this is much less
error prone regarding partial pages.
Reported-by: Roger Pau Monné <roger.pau@citrix.com>
Tested-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 70de4c8..f5ef674 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -90,62 +90,69 @@
xen_512gb_limit = val;
}
-static void __init xen_add_extra_mem(phys_addr_t start, phys_addr_t size)
+static void __init xen_add_extra_mem(unsigned long start_pfn,
+ unsigned long n_pfns)
{
int i;
+ /*
+ * No need to check for zero size, should happen rarely and will only
+ * write a new entry regarded to be unused due to zero size.
+ */
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
/* Add new region. */
- if (xen_extra_mem[i].size == 0) {
- xen_extra_mem[i].start = start;
- xen_extra_mem[i].size = size;
+ if (xen_extra_mem[i].n_pfns == 0) {
+ xen_extra_mem[i].start_pfn = start_pfn;
+ xen_extra_mem[i].n_pfns = n_pfns;
break;
}
/* Append to existing region. */
- if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
- xen_extra_mem[i].size += size;
+ if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns ==
+ start_pfn) {
+ xen_extra_mem[i].n_pfns += n_pfns;
break;
}
}
if (i == XEN_EXTRA_MEM_MAX_REGIONS)
printk(KERN_WARNING "Warning: not enough extra memory regions\n");
- memblock_reserve(start, size);
+ memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
}
-static void __init xen_del_extra_mem(phys_addr_t start, phys_addr_t size)
+static void __init xen_del_extra_mem(unsigned long start_pfn,
+ unsigned long n_pfns)
{
int i;
- phys_addr_t start_r, size_r;
+ unsigned long start_r, size_r;
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
- start_r = xen_extra_mem[i].start;
- size_r = xen_extra_mem[i].size;
+ start_r = xen_extra_mem[i].start_pfn;
+ size_r = xen_extra_mem[i].n_pfns;
/* Start of region. */
- if (start_r == start) {
- BUG_ON(size > size_r);
- xen_extra_mem[i].start += size;
- xen_extra_mem[i].size -= size;
+ if (start_r == start_pfn) {
+ BUG_ON(n_pfns > size_r);
+ xen_extra_mem[i].start_pfn += n_pfns;
+ xen_extra_mem[i].n_pfns -= n_pfns;
break;
}
/* End of region. */
- if (start_r + size_r == start + size) {
- BUG_ON(size > size_r);
- xen_extra_mem[i].size -= size;
+ if (start_r + size_r == start_pfn + n_pfns) {
+ BUG_ON(n_pfns > size_r);
+ xen_extra_mem[i].n_pfns -= n_pfns;
break;
}
/* Mid of region. */
- if (start > start_r && start < start_r + size_r) {
- BUG_ON(start + size > start_r + size_r);
- xen_extra_mem[i].size = start - start_r;
+ if (start_pfn > start_r && start_pfn < start_r + size_r) {
+ BUG_ON(start_pfn + n_pfns > start_r + size_r);
+ xen_extra_mem[i].n_pfns = start_pfn - start_r;
/* Calling memblock_reserve() again is okay. */
- xen_add_extra_mem(start + size, start_r + size_r -
- (start + size));
+ xen_add_extra_mem(start_pfn + n_pfns, start_r + size_r -
+ (start_pfn + n_pfns));
break;
}
}
- memblock_free(start, size);
+ memblock_free(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
}
/*
@@ -156,11 +163,10 @@
unsigned long __ref xen_chk_extra_mem(unsigned long pfn)
{
int i;
- phys_addr_t addr = PFN_PHYS(pfn);
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
- if (addr >= xen_extra_mem[i].start &&
- addr < xen_extra_mem[i].start + xen_extra_mem[i].size)
+ if (pfn >= xen_extra_mem[i].start_pfn &&
+ pfn < xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns)
return INVALID_P2M_ENTRY;
}
@@ -176,10 +182,10 @@
int i;
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
- if (!xen_extra_mem[i].size)
+ if (!xen_extra_mem[i].n_pfns)
continue;
- pfn_s = PFN_DOWN(xen_extra_mem[i].start);
- pfn_e = PFN_UP(xen_extra_mem[i].start + xen_extra_mem[i].size);
+ pfn_s = xen_extra_mem[i].start_pfn;
+ pfn_e = pfn_s + xen_extra_mem[i].n_pfns;
for (pfn = pfn_s; pfn < pfn_e; pfn++)
set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
}
@@ -507,7 +513,7 @@
} else if (pfn_s + len == xen_remap_buf.target_pfn) {
len += xen_remap_buf.size;
} else {
- xen_del_extra_mem(PFN_PHYS(pfn_s), PFN_PHYS(len));
+ xen_del_extra_mem(pfn_s, len);
pfn_s = xen_remap_buf.target_pfn;
len = xen_remap_buf.size;
}
@@ -517,7 +523,7 @@
}
if (pfn_s != ~0UL && len)
- xen_del_extra_mem(PFN_PHYS(pfn_s), PFN_PHYS(len));
+ xen_del_extra_mem(pfn_s, len);
set_pte_mfn(buf, mfn_save, PAGE_KERNEL);
@@ -744,7 +750,7 @@
**/
char * __init xen_memory_setup(void)
{
- unsigned long max_pfn;
+ unsigned long max_pfn, pfn_s, n_pfns;
phys_addr_t mem_end, addr, size, chunk_size;
u32 type;
int rc;
@@ -831,9 +837,11 @@
chunk_size = min(size, mem_end - addr);
} else if (extra_pages) {
chunk_size = min(size, PFN_PHYS(extra_pages));
- extra_pages -= PFN_DOWN(chunk_size);
- xen_add_extra_mem(addr, chunk_size);
- xen_max_p2m_pfn = PFN_DOWN(addr + chunk_size);
+ pfn_s = PFN_UP(addr);
+ n_pfns = PFN_DOWN(addr + chunk_size) - pfn_s;
+ extra_pages -= n_pfns;
+ xen_add_extra_mem(pfn_s, n_pfns);
+ xen_max_p2m_pfn = pfn_s + n_pfns;
} else
type = E820_UNUSABLE;
}
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index bf4a23c..1fa633b 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -638,9 +638,9 @@
* regions (see arch/x86/xen/setup.c).
*/
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++)
- if (xen_extra_mem[i].size)
- balloon_add_region(PFN_UP(xen_extra_mem[i].start),
- PFN_DOWN(xen_extra_mem[i].size));
+ if (xen_extra_mem[i].n_pfns)
+ balloon_add_region(xen_extra_mem[i].start_pfn,
+ xen_extra_mem[i].n_pfns);
return 0;
}
diff --git a/include/xen/page.h b/include/xen/page.h
index c5ed20b..a5983da 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -9,8 +9,8 @@
}
struct xen_memory_region {
- phys_addr_t start;
- phys_addr_t size;
+ unsigned long start_pfn;
+ unsigned long n_pfns;
};
#define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820MAX */