From 994038c817a4897c6272faf4b2725b3e79d34d6c Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 25 Sep 2018 21:17:23 -0400 Subject: [PATCH] target/arm: Fix cpu_get_tb_cpu_state() for non-SVE CPUs Not only are the sve-related tb_flags fields unused when SVE is disabled, but not all of the cpu registers are initialized properly for computing same. This can corrupt other fields by ORing in -1, which might result in QEMU crashing. This bug was not present in 3.0, but this patch is cc'd to stable because adf92eab90e3f5f34c285 where the bug was introduced was marked for stable. Backports commit e79b445d896deb61909be52b61b87c98a9ed96f7 from qemu --- qemu/target/arm/helper.c | 42 +++++++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 18 deletions(-) diff --git a/qemu/target/arm/helper.c b/qemu/target/arm/helper.c index 12e9d6de..53602bea 100644 --- a/qemu/target/arm/helper.c +++ b/qemu/target/arm/helper.c @@ -11817,33 +11817,39 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, uint32_t flags; if (is_a64(env)) { - int sve_el = sve_exception_el(env); - uint32_t zcr_len; - *pc = env->pc; flags = ARM_TBFLAG_AARCH64_STATE_MASK; /* Get control bits for tagged addresses */ flags |= (arm_regime_tbi0(env, mmu_idx) << ARM_TBFLAG_TBI0_SHIFT); flags |= (arm_regime_tbi1(env, mmu_idx) << ARM_TBFLAG_TBI1_SHIFT); - flags |= sve_el << ARM_TBFLAG_SVEEXC_EL_SHIFT; - /* If SVE is disabled, but FP is enabled, - then the effective len is 0. */ - if (sve_el != 0 && fp_el == 0) { - zcr_len = 0; - } else { - int current_el = arm_current_el(env); + if (arm_feature(env, ARM_FEATURE_SVE)) { + int sve_el = sve_exception_el(env); + uint32_t zcr_len; - zcr_len = env->vfp.zcr_el[current_el <= 1 ? 1 : current_el]; - zcr_len &= 0xf; - if (current_el < 2 && arm_feature(env, ARM_FEATURE_EL2)) { - zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[2]); - } - if (current_el < 3 && arm_feature(env, ARM_FEATURE_EL3)) { - zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[3]); + /* If SVE is disabled, but FP is enabled, + * then the effective len is 0. + */ + if (sve_el != 0 && fp_el == 0) { + zcr_len = 0; + } else { + int current_el = arm_current_el(env); + ARMCPU *cpu = arm_env_get_cpu(env); + + zcr_len = cpu->sve_max_vq - 1; + if (current_el <= 1) { + zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[1]); + } + if (current_el < 2 && arm_feature(env, ARM_FEATURE_EL2)) { + zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[2]); + } + if (current_el < 3 && arm_feature(env, ARM_FEATURE_EL3)) { + zcr_len = MIN(zcr_len, 0xf & (uint32_t)env->vfp.zcr_el[3]); + } } + flags |= sve_el << ARM_TBFLAG_SVEEXC_EL_SHIFT; + flags |= zcr_len << ARM_TBFLAG_ZCR_LEN_SHIFT; } - flags |= zcr_len << ARM_TBFLAG_ZCR_LEN_SHIFT; } else { *pc = env->regs[15]; flags = (env->thumb << ARM_TBFLAG_THUMB_SHIFT)