From 031b33ef1a6a1129a1a02a16b89608ded2eff9be Mon Sep 17 00:00:00 2001 From: "Chang S. Bae" Date: Thu, 20 Mar 2025 16:42:52 -0700 Subject: [PATCH] x86/fpu/xstate: Remove xstate offset check Traditionally, new xstate components have been assigned sequentially, aligning feature numbers with their offsets in the XSAVE buffer. However, this ordering is not architecturally mandated in the non-compacted format, where a component's offset may not correspond to its feature number. The kernel caches CPUID-reported xstate component details, including size and offset in the non-compacted format. As part of this process, a sanity check is also conducted to ensure alignment between feature numbers and offsets. This check was likely intended as a general guideline rather than a strict requirement. Upcoming changes will support out-of-order offsets. Remove the check as becoming obsolete. Signed-off-by: Chang S. Bae Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Link: https://lore.kernel.org/r/20250320234301.8342-2-chang.seok.bae@intel.com --- arch/x86/kernel/fpu/xstate.c | 13 ------------- 1 file changed, 13 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 6a41d1610d8bc..542c6981180d7 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -216,9 +216,6 @@ static bool xfeature_enabled(enum xfeature xfeature) static void __init setup_xstate_cache(void) { u32 eax, ebx, ecx, edx, i; - /* start at the beginning of the "extended state" */ - unsigned int last_good_offset = offsetof(struct xregs_state, - extended_state_area); /* * The FP xstates and SSE xstates are legacy states. They are always * in the fixed offsets in the xsave area in either compacted form @@ -246,16 +243,6 @@ static void __init setup_xstate_cache(void) continue; xstate_offsets[i] = ebx; - - /* - * In our xstate size checks, we assume that the highest-numbered - * xstate feature has the highest offset in the buffer. Ensure - * it does. - */ - WARN_ONCE(last_good_offset > xstate_offsets[i], - "x86/fpu: misordered xstate at %d\n", last_good_offset); - - last_good_offset = xstate_offsets[i]; } } -- 2.47.2