[PATCH 6/8] x86/cpufeatures: Re-enable ENQCMD

[Fenghua Yu]

Since ENQCMD is handled by #GP fix up, it can be re-enabled.

The ENQCMD feature cannot be used if CONFIG_INTEL_IOMMU_SVM
is not set. Add X86_FEATURE_ENQCMD to the disabled features mask as
appropriate and use cpu_feature_enabled() to check the feature.

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
---
 arch/x86/include/asm/disabled-features.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 8f28fafa98b3..1231d63f836d 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -56,8 +56,11 @@
 # define DISABLE_PTI		(1 << (X86_FEATURE_PTI & 31))
 #endif
 
-/* Force disable because it's broken beyond repair */
-#define DISABLE_ENQCMD		(1 << (X86_FEATURE_ENQCMD & 31))
+#ifdef CONFIG_INTEL_IOMMU_SVM
+# define DISABLE_ENQCMD		0
+#else
+# define DISABLE_ENQCMD		(1 << (X86_FEATURE_ENQCMD & 31))
+#endif
 
 #ifdef CONFIG_X86_SGX
 # define DISABLE_SGX	0
-- 
2.33.0