x86/xen: prepare p2m list for memory hotplug

[cascardo/linux.git] / arch / x86 / xen / p2m.c

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index f18fd1d..b47124d 100644 (file)
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -91,6 +91,12 @@ EXPORT_SYMBOL_GPL(xen_p2m_size);
 unsigned long xen_max_p2m_pfn __read_mostly;
 EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
 
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
+#define P2M_LIMIT CONFIG_XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
+#else
+#define P2M_LIMIT 0
+#endif
+
 static DEFINE_SPINLOCK(p2m_update_lock);
 
 static unsigned long *p2m_mid_missing_mfn;
@@ -385,9 +391,11 @@ static void __init xen_rebuild_p2m_list(unsigned long *p2m)
 void __init xen_vmalloc_p2m_tree(void)
 {
        static struct vm_struct vm;
+       unsigned long p2m_limit;
 
+       p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
        vm.flags = VM_ALLOC;
-       vm.size = ALIGN(sizeof(unsigned long) * xen_max_p2m_pfn,
+       vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
                        PMD_SIZE * PMDS_PER_MID_PAGE);
        vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
        pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
@@ -550,7 +558,7 @@ static bool alloc_p2m(unsigned long pfn)
                mid_mfn = NULL;
        }
 
-       p2m_pfn = pte_pfn(ACCESS_ONCE(*ptep));
+       p2m_pfn = pte_pfn(READ_ONCE(*ptep));
        if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
            p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
                /* p2m leaf page is missing */
@@ -563,7 +571,7 @@ static bool alloc_p2m(unsigned long pfn)
                if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
                        p2m_init(p2m);
                else
-                       p2m_init_identity(p2m, pfn);
+                       p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));
 
                spin_lock_irqsave(&p2m_update_lock, flags);