[PATCH 1/8] xen: Mark all initial reserved pages for the balloon as INVALID_P2M_ENTRY.

Konrad Rzeszutek Wilk
2010-12-30T19:50:21Z

With this patch, we diligently set regions that will be used by the
balloon driver to be INVALID_P2M_ENTRY and under the ownership
of the balloon driver. We are OK using the __set_phys_to_machine
as we do not expect to be allocating any P2M middle or entries pages.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/include/asm/xen/page.h | 1 +
arch/x86/xen/mmu.c | 12 ++++++------
arch/x86/xen/setup.c | 7 ++++++-
drivers/xen/balloon.c | 2 +-
4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 8760cc6..be671f6 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -41,6 +41,7 @@ extern unsigned int machine_to_phys_order;

extern unsigned long get_phys_to_machine(unsigned long pfn);
extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
+extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);

static inline unsigned long pfn_to_mfn(unsigned long pfn)
{
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 44924e5..8e9c669 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -503,6 +503,11 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
unsigned topidx, mididx, idx;

+ if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+ BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+ return true;
+ }
+
if (unlikely(pfn >= MAX_P2M_PFN)) {
BUG_ON(mfn != INVALID_P2M_ENTRY);
return true;
@@ -522,11 +527,6 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)

bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
{
- if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
- BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
- return true;
- }
-
if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
if (!alloc_p2m(pfn))
return false;
@@ -2438,7 +2438,7 @@ static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
in_frames[i] = virt_to_mfn(vaddr);

MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
- set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
+ __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);

if (out_frames)
out_frames[i] = virt_to_pfn(vaddr);
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index b5a7f92..7201800 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size;

static __init void xen_add_extra_mem(unsigned long pages)
{
+ unsigned long pfn;
+
u64 size = (u64)pages * PAGE_SIZE;
u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;

@@ -66,6 +68,9 @@ static __init void xen_add_extra_mem(unsigned long pages)
xen_extra_mem_size += size;

xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
+
+ for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
+ __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
}

static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
@@ -104,7 +109,7 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
start, end, ret);
if (ret == 1) {
- set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+ __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
len++;
}
}
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 43f9f02..b1661cd 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -296,7 +296,7 @@ static int decrease_reservation(unsigned long nr_pages)
/* No more mappings: invalidate P2M and add to balloon. */
for (i = 0; i < nr_pages; i++) {
pfn = mfn_to_pfn(frame_list[i]);
- set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+ __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
balloon_append(pfn_to_page(pfn));
}

--
1.7.1