From 3cdd1f45aa55d77c6a04a546013de911eec3cced Mon Sep 17 00:00:00 2001 From: Chao Liu Date: Mon, 10 Mar 2025 10:35:25 +0800 Subject: [PATCH] target/riscv: fix handling of nop for vstart >= vl in some vector instruction Recently, when I was writing a RISCV test, I found that when VL is set to 0, the instruction should be nop, but when I tested it, I found that QEMU will treat all elements as tail elements, and in the case of VTA=1, write all elements to 1. After troubleshooting, it was found that the vext_vx_rm_1 function was called in the vext_vx_rm_2, and then the vext_set_elems_1s function was called to process the tail element, but only VSTART >= vl was checked in the vext_vx_rm_1 function, which caused the tail element to still be processed even if it was returned in advance. So I've made the following change: Put VSTART_CHECK_EARLY_EXIT(env) at the beginning of the vext_vx_rm_2 function, so that the VSTART register is checked correctly. Fixes: df4252b2ec ("target/riscv/vector_helpers: do early exit when vstart >= vl") Signed-off-by: Chao Liu Reviewed-by: Daniel Henrique Barboza Message-ID: Signed-off-by: Alistair Francis (cherry picked from commit 4e9e2478dfd26480bbf50367a67b9be0edafef2b) Signed-off-by: Michael Tokarev --- target/riscv/vector_helper.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c index 08c7b4eaaf..9394a7233c 100644 --- a/target/riscv/vector_helper.c +++ b/target/riscv/vector_helper.c @@ -2151,8 +2151,6 @@ vext_vv_rm_1(void *vd, void *v0, void *vs1, void *vs2, uint32_t vl, uint32_t vm, int vxrm, opivv2_rm_fn *fn, uint32_t vma, uint32_t esz) { - VSTART_CHECK_EARLY_EXIT(env, vl); - for (uint32_t i = env->vstart; i < vl; i++) { if (!vm && !vext_elem_mask(v0, i)) { /* set masked-off elements to 1s */ @@ -2176,6 +2174,8 @@ vext_vv_rm_2(void *vd, void *v0, void *vs1, void *vs2, uint32_t vta = vext_vta(desc); uint32_t vma = vext_vma(desc); + VSTART_CHECK_EARLY_EXIT(env, vl); + switch (env->vxrm) { case 0: /* rnu */ vext_vv_rm_1(vd, v0, vs1, vs2, @@ -2278,8 +2278,6 @@ vext_vx_rm_1(void *vd, void *v0, target_long s1, void *vs2, uint32_t vl, uint32_t vm, int vxrm, opivx2_rm_fn *fn, uint32_t vma, uint32_t esz) { - VSTART_CHECK_EARLY_EXIT(env, vl); - for (uint32_t i = env->vstart; i < vl; i++) { if (!vm && !vext_elem_mask(v0, i)) { /* set masked-off elements to 1s */ @@ -2303,6 +2301,8 @@ vext_vx_rm_2(void *vd, void *v0, target_long s1, void *vs2, uint32_t vta = vext_vta(desc); uint32_t vma = vext_vma(desc); + VSTART_CHECK_EARLY_EXIT(env, vl); + switch (env->vxrm) { case 0: /* rnu */ vext_vx_rm_1(vd, v0, s1, vs2, @@ -4638,6 +4638,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, \ uint32_t i; \ TD s1 = *((TD *)vs1 + HD(0)); \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ TS2 s2 = *((TS2 *)vs2 + HS2(i)); \ if (!vm && !vext_elem_mask(v0, i)) { \ @@ -4726,6 +4728,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, \ uint32_t i; \ TD s1 = *((TD *)vs1 + HD(0)); \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ TS2 s2 = *((TS2 *)vs2 + HS2(i)); \ if (!vm && !vext_elem_mask(v0, i)) { \ @@ -4890,6 +4894,8 @@ static void vmsetm(void *vd, void *v0, void *vs2, CPURISCVState *env, int i; bool first_mask_bit = false; + VSTART_CHECK_EARLY_EXIT(env, vl); + for (i = env->vstart; i < vl; i++) { if (!vm && !vext_elem_mask(v0, i)) { /* set masked-off elements to 1s */ @@ -4962,6 +4968,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs2, CPURISCVState *env, \ uint32_t sum = 0; \ int i; \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ if (!vm && !vext_elem_mask(v0, i)) { \ /* set masked-off elements to 1s */ \ @@ -5320,6 +5328,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, void *vs2, \ uint32_t vta = vext_vta(desc); \ uint32_t num = 0, i; \ \ + VSTART_CHECK_EARLY_EXIT(env, vl); \ + \ for (i = env->vstart; i < vl; i++) { \ if (!vext_elem_mask(vs1, i)) { \ continue; \ -- 2.39.5