File 60be3097-x86-CPUID-fix-HLE-and-RTM-handling-aga... of Package xen.21116

Overview Repositories Revisions Requests Users Attributes Meta

File 60be3097-x86-CPUID-fix-HLE-and-RTM-handling-again.patch of Package xen.21116

# Commit 60fa12dbf1d4d2c4ffe1ef34b495b24aa7e41aa0
# Date 2021-06-07 15:43:35 +0100
# Author Andrew Cooper <andrew.cooper3@citrix.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
x86/cpuid: Fix HLE and RTM handling (again)

For reasons which are my fault, but I don't recall why, the
FDP_EXCP_ONLY/NO_FPU_SEL adjustment uses the whole special_features[] array
element, not the two relevant bits.

HLE and RTM were recently added to the list of special features, causing them
to be always set in guest view, irrespective of the toolstacks choice on the
matter.

Rewrite the logic to refer to the features specifically, rather than relying
on the contents of the special_features[] array.

Fixes: 8fe24090d9 ("x86/cpuid: Rework HLE and RTM handling")
Reported-by: Edwin Török <edvin.torok@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -648,9 +648,11 @@ void recalculate_cpuid_policy(struct dom
     sanitise_featureset(fs);
 
     /* Fold host's FDP_EXCP_ONLY and NO_FPU_SEL into guest's view. */
-    fs[FEATURESET_7b0] &= ~special_features[FEATURESET_7b0];
+    fs[FEATURESET_7b0] &= ~(cpufeat_mask(X86_FEATURE_FDP_EXCP_ONLY) |
+                            cpufeat_mask(X86_FEATURE_NO_FPU_SEL));
     fs[FEATURESET_7b0] |= (host_cpuid_policy.feat._7b0 &
-                           special_features[FEATURESET_7b0]);
+                           (cpufeat_mask(X86_FEATURE_FDP_EXCP_ONLY) |
+                            cpufeat_mask(X86_FEATURE_NO_FPU_SEL)));
 
     cpuid_featureset_to_policy(fs, p);

Places

File 60be3097-x86-CPUID-fix-HLE-and-RTM-handling-again.patch of Package xen.21116

Places