x86/xstate: Don't special case feature collection

The logic in xstate_init() is a rementent of the pre-featuremask days.
Collect the xstate features in generic_identify(), like all other feature
leaves, after which identify_cpu() will apply the known_feature[] mask derived
from the automatically generated CPUID information.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
master commit: 65c165d659
master date: 2019-03-12 13:57:13 +0000

xen/arch/x86/cpu/common.c

@@ -414,6 +414,10 @@ static void generic_identify(struct cpuinfo_x86 *c)
 			    &c->x86_capability[cpufeat_word(X86_FEATURE_FSGSBASE)],
 			    &c->x86_capability[cpufeat_word(X86_FEATURE_PKU)],
 			    &c->x86_capability[cpufeat_word(X86_FEATURE_AVX512_4VNNIW)]);
+	if (c->cpuid_level >= 0xd)
+		cpuid_count(0xd, 1,
+			    &c->x86_capability[cpufeat_word(X86_FEATURE_XSAVEOPT)],
+			    &tmp, &tmp, &tmp);
 }
 
 /*

xen/arch/x86/xstate.c

@@ -628,19 +628,6 @@ void xstate_init(struct cpuinfo_x86 *c)
         BUG_ON(xsave_cntxt_size != _xstate_ctxt_size(feature_mask));
     }
 
-    /* Check extended XSAVE features. */
-    cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
-
-    /* Mask out features not currently understood by Xen. */
-    eax &= (cpufeat_mask(X86_FEATURE_XSAVEOPT) |
-            cpufeat_mask(X86_FEATURE_XSAVEC) |
-            cpufeat_mask(X86_FEATURE_XGETBV1) |
-            cpufeat_mask(X86_FEATURE_XSAVES));
-
-    c->x86_capability[cpufeat_word(X86_FEATURE_XSAVEOPT)] = eax;
-
-    BUG_ON(eax != boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_XSAVEOPT)]);
-
     if ( setup_xstate_features(bsp) && bsp )
         BUG();
 }