x86: work around HLE host lockup erratum

XACQUIRE prefixed accesses to the 4Mb range of memory starting at 1Gb
are liable to lock up the processor. Disallow use of this memory range.

Unfortunately the available Core Gen7 and Gen8 spec updates are pretty
old, so I can only guess that they're similarly affected when Core Gen6
is and the Xeon counterparts are, too.

This is part of XSA-282.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: cc76410d20aff2cc07b268b0713dc1d2740c6e12
master date: 2018-11-07 09:33:24 +0100

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 59d05862f0b193cb6ce3ac5613f9cfa4ce1a8b9e..66530c8a9ba14d02765d28e175651bdb8d972e7d 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -6983,6 +6983,25 @@ const struct platform_bad_page *__init get_platform_badpages(unsigned int *array
         { .mfn = 0x20138000 >> PAGE_SHIFT },
         { .mfn = 0x40004000 >> PAGE_SHIFT },
     };
+    static const struct platform_bad_page __initconst hle_bad_page = {
+        .mfn = 0x40000000 >> PAGE_SHIFT, .order = 10
+    };
+
+    switch ( cpuid_eax(1) & 0x000f3ff0 )
+    {
+        unsigned int ebx, dummy;
+
+    case 0x000406e0: /* erratum SKL167 */
+    case 0x00050650: /* erratum SKZ63 */
+    case 0x000506e0: /* errata SKL167 / SKW159 */
+    case 0x000806e0: /* erratum KBL??? */
+    case 0x000906e0: /* errata KBL??? / KBW114 / CFW103 */
+        *array_size = (cpuid_eax(0) >= 7 &&
+                       !(cpuid_ecx(1) & cpufeat_mask(X86_FEATURE_HYPERVISOR)) &&
+                       (cpuid_count(7, 0, &dummy, &ebx, &dummy, &dummy),
+                        ebx & cpufeat_mask(X86_FEATURE_HLE)));
+        return &hle_bad_page;
+    }
 
     *array_size = ARRAY_SIZE(snb_bad_pages);
     igd_id = pci_conf_read32(0, 0, 2, 0, 0);