From 626d7508664c4bc8e67f496da4387ecd0c410b8c Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Fri, 4 Sep 2015 14:05:51 +0200
Subject: [PATCH] xen: switch extra memory accounting to use pfns
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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>
---
arch/x86/xen/setup.c | 80 ++++++++++++++++++++++++-------------------
drivers/xen/balloon.c | 6 ++--
include/xen/page.h | 4 +--
3 files changed, 49 insertions(+), 41 deletions(-)
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 70de4c8b8f27..f5ef6746d47a 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -90,62 +90,69 @@ static void __init xen_parse_512gb(void)
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 @@ static void __init xen_del_extra_mem(phys_addr_t start, phys_addr_t size)
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 @@ void __init xen_inv_extra_mem(void)
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 @@ void __init xen_remap_memory(void)
} 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 @@ void __init xen_remap_memory(void)
}
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 @@ static void __init xen_reserve_xen_mfnlist(void)
**/
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 @@ char * __init xen_memory_setup(void)
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 bf4a23c7c591..1fa633b2d556 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -638,9 +638,9 @@ static int __init balloon_init(void)
* 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 c5ed20bb3fe9..a5983da2f5cd 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -9,8 +9,8 @@ static inline unsigned long page_to_mfn(struct page *page)
}
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 */