From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- arch/arc/lib/memset.S | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 arch/arc/lib/memset.S (limited to 'arch/arc/lib/memset.S') diff --git a/arch/arc/lib/memset.S b/arch/arc/lib/memset.S new file mode 100644 index 000000000..9f35960da --- /dev/null +++ b/arch/arc/lib/memset.S @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + */ + +#include + +#define SMALL 7 /* Must be at least 6 to deal with alignment/loop issues. */ + +ENTRY_CFI(memset) + mov_s r4,r0 + or r12,r0,r2 + bmsk.f r12,r12,1 + extb_s r1,r1 + asl r3,r1,8 + beq.d .Laligned + or_s r1,r1,r3 + brls r2,SMALL,.Ltiny + add r3,r2,r0 + stb r1,[r3,-1] + bclr_s r3,r3,0 + stw r1,[r3,-2] + bmsk.f r12,r0,1 + add_s r2,r2,r12 + sub.ne r2,r2,4 + stb.ab r1,[r4,1] + and r4,r4,-2 + stw.ab r1,[r4,2] + and r4,r4,-4 +.Laligned: ; This code address should be aligned for speed. + asl r3,r1,16 + lsr.f lp_count,r2,2 + or_s r1,r1,r3 + lpne .Loop_end + st.ab r1,[r4,4] +.Loop_end: + j_s [blink] + + .balign 4 +.Ltiny: + mov.f lp_count,r2 + lpne .Ltiny_end + stb.ab r1,[r4,1] +.Ltiny_end: + j_s [blink] +END_CFI(memset) + +; memzero: @r0 = mem, @r1 = size_t +; memset: @r0 = mem, @r1 = char, @r2 = size_t + +ENTRY_CFI(memzero) + ; adjust bzero args to memset args + mov r2, r1 + mov r1, 0 + b memset ;tail call so need to tinker with blink +END_CFI(memzero) -- cgit v1.3.1