xen: allow more than 512 GB of RAM for 64 bit pv-domains

[firefly-linux-kernel-4.4.55.git] / arch / x86 / xen / setup.c

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index b096d02d34ac5319877f1714a2caa9a3b5fa5103..f96002107691a5417d8c3bad4a51572e85e59720 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -33,6 +33,8 @@
 #include "p2m.h"
 #include "mmu.h"
 
+#define GB(x) ((uint64_t)(x) * 1024 * 1024 * 1024)
+
 /* Amount of extra memory space we add to the e820 ranges */
 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
 
@@ -69,6 +71,26 @@ static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY;
  */
 #define EXTRA_MEM_RATIO                (10)
 
+static bool xen_512gb_limit __initdata = IS_ENABLED(CONFIG_XEN_512GB);
+
+static void __init xen_parse_512gb(void)
+{
+       bool val = false;
+       char *arg;
+
+       arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit");
+       if (!arg)
+               return;
+
+       arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit=");
+       if (!arg)
+               val = true;
+       else if (strtobool(arg + strlen("xen_512gb_limit="), &val))
+               return;
+
+       xen_512gb_limit = val;
+}
+
 static void __init xen_add_extra_mem(phys_addr_t start, phys_addr_t size)
 {
        int i;
@@ -503,12 +525,29 @@ void __init xen_remap_memory(void)
        pr_info("Remapped %ld page(s)\n", remapped);
 }
 
+static unsigned long __init xen_get_pages_limit(void)
+{
+       unsigned long limit;
+
+#ifdef CONFIG_X86_32
+       limit = GB(64) / PAGE_SIZE;
+#else
+       limit = ~0ul;
+       if (!xen_initial_domain() && xen_512gb_limit)
+               limit = GB(512) / PAGE_SIZE;
+#endif
+       return limit;
+}
+
 static unsigned long __init xen_get_max_pages(void)
 {
-       unsigned long max_pages = MAX_DOMAIN_PAGES;
+       unsigned long max_pages, limit;
        domid_t domid = DOMID_SELF;
        int ret;
 
+       limit = xen_get_pages_limit();
+       max_pages = limit;
+
        /*
         * For the initial domain we use the maximum reservation as
         * the maximum page.
@@ -524,7 +563,7 @@ static unsigned long __init xen_get_max_pages(void)
                        max_pages = ret;
        }
 
-       return min(max_pages, MAX_DOMAIN_PAGES);
+       return min(max_pages, limit);
 }
 
 static void __init xen_align_and_add_e820_region(phys_addr_t start,
@@ -699,7 +738,7 @@ static void __init xen_reserve_xen_mfnlist(void)
  **/
 char * __init xen_memory_setup(void)
 {
-       unsigned long max_pfn = xen_start_info->nr_pages;
+       unsigned long max_pfn;
        phys_addr_t mem_end, addr, size, chunk_size;
        u32 type;
        int rc;
@@ -709,7 +748,9 @@ char * __init xen_memory_setup(void)
        int i;
        int op;
 
-       max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
+       xen_parse_512gb();
+       max_pfn = xen_get_pages_limit();
+       max_pfn = min(max_pfn, xen_start_info->nr_pages);
        mem_end = PFN_PHYS(max_pfn);
 
        memmap.nr_entries = E820MAX;
@@ -762,12 +803,15 @@ char * __init xen_memory_setup(void)
         * is limited to the max size of lowmem, so that it doesn't
         * get completely filled.
         *
+        * Make sure we have no memory above max_pages, as this area
+        * isn't handled by the p2m management.
+        *
         * In principle there could be a problem in lowmem systems if
         * the initial memory is also very large with respect to
         * lowmem, but we won't try to deal with that here.
         */
-       extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
-                         extra_pages);
+       extra_pages = min3(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+                          extra_pages, max_pages - max_pfn);
        i = 0;
        addr = xen_e820_map[0].addr;
        size = xen_e820_map[0].size;
@@ -803,9 +847,6 @@ char * __init xen_memory_setup(void)
        /*
         * Set the rest as identity mapped, in case PCI BARs are
         * located here.
-        *
-        * PFNs above MAX_P2M_PFN are considered identity mapped as
-        * well.
         */
        set_phys_range_identity(addr / PAGE_SIZE, ~0ul);