Commit b1599915 authored Nov 06, 2022 by Ingo Molnar

x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11,...


x86/cpufeatures: Move X86_FEATURE_CALL_DEPTH from bit 18 to bit 19 of word 11, to leave space for WIP X86_FEATURE_SGX_EDECCSSA bit

Reallocate a soft-cpufeatures bit allocated for call-depth tracking
code, which clashes with this recent KVM/SGX patch being worked on:

        KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest

Instead of reallocating cpufeatures bits in evil merges, make the
allocation explicit.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 4fd5f70c

arch/x86/include/asm/cpufeatures.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -304,7 +304,8 @@
		#define X86_FEATURE_UNRET (1132+15) / "" AMD BTB untrain return */
		#define X86_FEATURE_USE_IBPB_FW (1132+16) / "" Use IBPB during runtime firmware calls */
		#define X86_FEATURE_RSB_VMEXIT_LITE (1132+17) / "" Fill RSB on VM exit when EIBRS is enabled */
		#define X86_FEATURE_CALL_DEPTH (1132+18) / "" Call depth tracking for RSB stuffing */
		/* Hole left for X86_FEATURE_SGX_EDECCSSA */
		#define X86_FEATURE_CALL_DEPTH (1132+19) / "" Call depth tracking for RSB stuffing */

		/* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
		#define X86_FEATURE_AVX_VNNI (1232+ 4) / AVX VNNI instructions */