From patchwork Fri May 17 03:06:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bibo Mao X-Patchwork-Id: 13666611 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2017DC25B74 for ; Fri, 17 May 2024 03:07:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s7nvx-0000y4-Aa; Thu, 16 May 2024 23:07:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1s7nvv-0000xu-BZ for qemu-devel@nongnu.org; Thu, 16 May 2024 23:06:59 -0400 Received: from mail.loongson.cn ([114.242.206.163]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s7nvn-0004pk-Oh for qemu-devel@nongnu.org; Thu, 16 May 2024 23:06:54 -0400 Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8CxBevGyUZmY8sNAA--.21379S3; Fri, 17 May 2024 11:06:46 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8DxebrFyUZm6tsjAA--.4054S2; Fri, 17 May 2024 11:06:45 +0800 (CST) From: Bibo Mao To: Song Gao Cc: qemu-devel@nongnu.org Subject: [RFC v2] target/loongarch/kvm: Add software breakpoint support Date: Fri, 17 May 2024 11:06:45 +0800 Message-Id: <20240517030645.3572411-1-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 MIME-Version: 1.0 X-CM-TRANSID: AQAAf8DxebrFyUZm6tsjAA--.4054S2 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7KY7 ZEXasCq-sGcSsGvfJ3UbIjqfuFe4nvWSU5nxnvy29KBjDU0xBIdaVrnUUvcSsGvfC2Kfnx nUUI43ZEXa7xR_UUUUUUUUU== Received-SPF: pass client-ip=114.242.206.163; envelope-from=maobibo@loongson.cn; helo=mail.loongson.cn X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org With KVM virtualization, debug exception is passthrough to guest kernel rather than host mode. Here hypercall instruction with special code is used for sw breakpoint usage. Now only software breakpoint is supported, and it is allowed to insert/remove software breakpoint. We can debug guest kernel with gdb method after kernel is loaded, hardware breakpoint will be added in later. Signed-off-by: Bibo Mao --- v1 ... v2: 1. Enable TARGET_KVM_HAVE_GUEST_DEBUG on loongarch64 platform --- configs/targets/loongarch64-softmmu.mak | 1 + target/loongarch/kvm/kvm.c | 76 +++++++++++++++++++++++++ 2 files changed, 77 insertions(+) base-commit: 922582ace2df59572a671f5c0c5c6c5c706995e5 diff --git a/configs/targets/loongarch64-softmmu.mak b/configs/targets/loongarch64-softmmu.mak index 84beb19b90..65b65e0c34 100644 --- a/configs/targets/loongarch64-softmmu.mak +++ b/configs/targets/loongarch64-softmmu.mak @@ -1,5 +1,6 @@ TARGET_ARCH=loongarch64 TARGET_BASE_ARCH=loongarch +TARGET_KVM_HAVE_GUEST_DEBUG=y TARGET_SUPPORTS_MTTCG=y TARGET_XML_FILES= gdb-xml/loongarch-base32.xml gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml # all boards require libfdt diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c index bc75552d0f..0a94784276 100644 --- a/target/loongarch/kvm/kvm.c +++ b/target/loongarch/kvm/kvm.c @@ -28,6 +28,7 @@ #include "trace.h" static bool cap_has_mp_state; +static unsigned int brk_insn; const KVMCapabilityInfo kvm_arch_required_capabilities[] = { KVM_CAP_LAST_INFO }; @@ -658,7 +659,14 @@ static void kvm_loongarch_vm_stage_change(void *opaque, bool running, int kvm_arch_init_vcpu(CPUState *cs) { + uint64_t val; + qemu_add_vm_change_state_handler(kvm_loongarch_vm_stage_change, cs); + + if (!kvm_get_one_reg(cs, KVM_REG_LOONGARCH_DEBUG_INST, &val)) { + brk_insn = val; + } + return 0; } @@ -733,6 +741,67 @@ bool kvm_arch_stop_on_emulation_error(CPUState *cs) return true; } +void kvm_arch_update_guest_debug(CPUState *cpu, struct kvm_guest_debug *dbg) +{ + if (kvm_sw_breakpoints_active(cpu)) { + dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP; + } +} + +int kvm_arch_insert_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp) +{ + if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn, 4, 0) || + cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&brk_insn, 4, 1)) { + error_report("%s failed", __func__); + return -EINVAL; + } + return 0; +} + +int kvm_arch_remove_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp) +{ + static uint32_t brk; + + if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&brk, 4, 0) || + brk != brk_insn || + cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn, 4, 1)) { + error_report("%s failed", __func__); + return -EINVAL; + } + return 0; +} + +int kvm_arch_insert_hw_breakpoint(vaddr addr, vaddr len, int type) +{ + return -ENOSYS; +} + +int kvm_arch_remove_hw_breakpoint(vaddr addr, vaddr len, int type) +{ + return -ENOSYS; +} + +void kvm_arch_remove_all_hw_breakpoints(void) +{ +} + +static bool kvm_loongarch_handle_debug(CPUState *cs, struct kvm_run *run) +{ + LoongArchCPU *cpu = LOONGARCH_CPU(cs); + CPULoongArchState *env = &cpu->env; + + kvm_cpu_synchronize_state(cs); + if (cs->singlestep_enabled) { + return true; + } + + if (kvm_find_sw_breakpoint(cs, env->pc)) { + return true; + } + + return false; +} + int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run) { int ret = 0; @@ -751,6 +820,13 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run) run->iocsr_io.len, run->iocsr_io.is_write); break; + + case KVM_EXIT_DEBUG: + if (kvm_loongarch_handle_debug(cs, run)) { + ret = EXCP_DEBUG; + } + break; + default: ret = -1; warn_report("KVM: unknown exit reason %d", run->exit_reason);