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Subject[PATCH 2/4] xen/x86: Use memblock_reserve for sensitive areas.
Date
instead of a big memblock_reserve. This way we can be more
selective in freeing regions (and it also makes it easier
to understand where is what).

[v1: Move the auto_translate_physmap to proper line]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/enlighten.c | 38 ++++++++++++++++++++++++++++++++++++++
arch/x86/xen/p2m.c | 5 +++++
arch/x86/xen/setup.c | 9 ---------
3 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index ff962d4..9b1afa4 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -998,7 +998,44 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)

return ret;
}
+static void __init xen_reserve_mfn(unsigned long mfn)
+{
+ unsigned long pfn;
+
+ if (!mfn)
+ return;
+ pfn = mfn_to_pfn(mfn);
+ if (phys_to_machine_mapping_valid(pfn))
+ memblock_reserve(PFN_PHYS(pfn), PAGE_SIZE);
+}
+static void __init xen_reserve_internals(void)
+{
+ unsigned long size;
+
+ if (!xen_pv_domain())
+ return;
+
+ memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
+
+ xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info));
+ xen_reserve_mfn(xen_start_info->store_mfn);

+ if (!xen_initial_domain())
+ xen_reserve_mfn(xen_start_info->console.domU.mfn);
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ /*
+ * ALIGN up to compensate for the p2m_page pointing to an array that
+ * can partially filled (look in xen_build_dynamic_phys_to_machine).
+ */
+
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+ memblock_reserve(__pa(xen_start_info->mfn_list), size);
+
+ /* The pagetables are reserved in mmu.c */
+}
void xen_setup_shared_info(void)
{
if (!xen_feature(XENFEAT_auto_translated_physmap)) {
@@ -1362,6 +1399,7 @@ asmlinkage void __init xen_start_kernel(void)
xen_raw_console_write("mapping kernel into physical memory\n");
pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);

+ xen_reserve_internals();
/* Allocate and initialize top and mid mfn levels for p2m structure */
xen_build_mfn_list_list();

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index e4adbfb..6a2bfa4 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -388,6 +388,11 @@ void __init xen_build_dynamic_phys_to_machine(void)
}

m2p_override_init();
+
+ /* NOTE: We cannot call memblock_reserve here for the mfn_list as there
+ * isn't enough pieces to make it work (for one - we are still using the
+ * Xen provided pagetable). Do it later in xen_reserve_internals.
+ */
}

unsigned long get_phys_to_machine(unsigned long pfn)
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index a4790bf..9efca75 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -424,15 +424,6 @@ char * __init xen_memory_setup(void)
e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
E820_RESERVED);

- /*
- * Reserve Xen bits:
- * - mfn_list
- * - xen_start_info
- * See comment above "struct start_info" in <xen/interface/xen.h>
- */
- memblock_reserve(__pa(xen_start_info->mfn_list),
- xen_start_info->pt_base - xen_start_info->mfn_list);
-
sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

return "Xen";
--
1.7.7.6


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