98 lines
3.5 KiB
Diff
98 lines
3.5 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Richard Henderson <richard.henderson@linaro.org>
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Date: Sat, 14 Jan 2023 13:05:42 -1000
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Subject: [PATCH] target/i386: Fix BEXTR instruction
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There were two problems here: not limiting the input to operand bits,
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and not correctly handling large extraction length.
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Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1372
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Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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Message-Id: <20230114230542.3116013-3-richard.henderson@linaro.org>
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Cc: qemu-stable@nongnu.org
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Fixes: 1d0b926150e5 ("target/i386: move scalar 0F 38 and 0F 3A instruction to new decoder", 2022-10-18)
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry-picked from commit b14c0098975264ed03144f145bca0179a6763a07)
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Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
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---
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target/i386/tcg/emit.c.inc | 22 +++++++++++-----------
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tests/tcg/i386/test-i386-bmi2.c | 12 ++++++++++++
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2 files changed, 23 insertions(+), 11 deletions(-)
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diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
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index 7037ff91c6..99f6ba6e19 100644
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--- a/target/i386/tcg/emit.c.inc
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+++ b/target/i386/tcg/emit.c.inc
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@@ -1078,30 +1078,30 @@ static void gen_ANDN(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode)
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static void gen_BEXTR(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode)
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{
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MemOp ot = decode->op[0].ot;
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- TCGv bound, zero;
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+ TCGv bound = tcg_constant_tl(ot == MO_64 ? 63 : 31);
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+ TCGv zero = tcg_constant_tl(0);
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+ TCGv mone = tcg_constant_tl(-1);
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/*
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* Extract START, and shift the operand.
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* Shifts larger than operand size get zeros.
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*/
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tcg_gen_ext8u_tl(s->A0, s->T1);
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+ if (TARGET_LONG_BITS == 64 && ot == MO_32) {
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+ tcg_gen_ext32u_tl(s->T0, s->T0);
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+ }
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tcg_gen_shr_tl(s->T0, s->T0, s->A0);
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- bound = tcg_constant_tl(ot == MO_64 ? 63 : 31);
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- zero = tcg_constant_tl(0);
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tcg_gen_movcond_tl(TCG_COND_LEU, s->T0, s->A0, bound, s->T0, zero);
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/*
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- * Extract the LEN into a mask. Lengths larger than
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- * operand size get all ones.
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+ * Extract the LEN into an inverse mask. Lengths larger than
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+ * operand size get all zeros, length 0 gets all ones.
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*/
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tcg_gen_extract_tl(s->A0, s->T1, 8, 8);
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- tcg_gen_movcond_tl(TCG_COND_LEU, s->A0, s->A0, bound, s->A0, bound);
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-
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- tcg_gen_movi_tl(s->T1, 1);
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- tcg_gen_shl_tl(s->T1, s->T1, s->A0);
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- tcg_gen_subi_tl(s->T1, s->T1, 1);
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- tcg_gen_and_tl(s->T0, s->T0, s->T1);
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+ tcg_gen_shl_tl(s->T1, mone, s->A0);
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+ tcg_gen_movcond_tl(TCG_COND_LEU, s->T1, s->A0, bound, s->T1, zero);
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+ tcg_gen_andc_tl(s->T0, s->T0, s->T1);
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gen_op_update1_cc(s);
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set_cc_op(s, CC_OP_LOGICB + ot);
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diff --git a/tests/tcg/i386/test-i386-bmi2.c b/tests/tcg/i386/test-i386-bmi2.c
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index 3c3ef85513..982d4abda4 100644
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--- a/tests/tcg/i386/test-i386-bmi2.c
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+++ b/tests/tcg/i386/test-i386-bmi2.c
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@@ -99,6 +99,9 @@ int main(int argc, char *argv[]) {
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result = bextrq(mask, 0x10f8);
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assert(result == 0);
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+ result = bextrq(0xfedcba9876543210ull, 0x7f00);
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+ assert(result == 0xfedcba9876543210ull);
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+
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result = blsiq(0x30);
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assert(result == 0x10);
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@@ -164,6 +167,15 @@ int main(int argc, char *argv[]) {
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result = bextrl(mask, 0x1038);
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assert(result == 0);
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+ result = bextrl((reg_t)0x8f635a775ad3b9b4ull, 0x3018);
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+ assert(result == 0x5a);
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+
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+ result = bextrl((reg_t)0xfedcba9876543210ull, 0x7f00);
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+ assert(result == 0x76543210u);
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+
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+ result = bextrl(-1, 0);
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+ assert(result == 0);
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+
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result = blsil(0xffff);
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assert(result == 1);
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