On Wed, Jun 02 2021 at 12:14, Borislav Petkov wrote:

On Sat, May 29, 2021 at 11:17:30AM +0200, Thomas Gleixner wrote:

quoted

--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h

@@ -56,11 +56,8 @@
 # define DISABLE_PTI		(1 << (X86_FEATURE_PTI & 31))
 #endif
 
-#ifdef CONFIG_IOMMU_SUPPORT
-# define DISABLE_ENQCMD	0
-#else
-# define DISABLE_ENQCMD (1 << (X86_FEATURE_ENQCMD & 31))
-#endif
+/* Force disable because it's broken beyond repair */
+#define DISABLE_ENQCMD		(1 << (X86_FEATURE_ENQCMD & 31))

Yeah, for that to work we need:

---
From: Borislav Petkov <redacted>
Date: Wed, 2 Jun 2021 12:07:52 +0200
Subject: [PATCH] dmaengine: idxd: Use cpu_feature_enabled()

When testing x86 feature bits, use cpu_feature_enabled() so that
build-disabled features can remain off, regardless of what CPUID says.

Fixes: 8e50d392652f ("dmaengine: idxd: Add shared workqueue support")
Signed-off-by: Borislav Petkov <redacted>
Cc: <redacted>

Reviewed-by: Thomas Gleixner <redacted>

Thanks for spotting this!

       tglx