From patchwork Fri Jun 7 03:50:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bibo Mao X-Patchwork-Id: 13689232 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 D3A08C27C53 for ; Fri, 7 Jun 2024 03:51:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sFQcV-0005aA-Ie; Thu, 06 Jun 2024 23:50:27 -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 1sFQcT-0005a1-Os for qemu-devel@nongnu.org; Thu, 06 Jun 2024 23:50:25 -0400 Received: from mail.loongson.cn ([114.242.206.163]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sFQcQ-00073s-Nw for qemu-devel@nongnu.org; Thu, 06 Jun 2024 23:50:25 -0400 Received: from loongson.cn (unknown [10.2.5.213]) by gateway (Coremail) with SMTP id _____8Cx_ep4g2JmnHwEAA--.18838S3; Fri, 07 Jun 2024 11:50:16 +0800 (CST) Received: from localhost.localdomain (unknown [10.2.5.213]) by localhost.localdomain (Coremail) with SMTP id AQAAf8AxRcV4g2JmCL0XAA--.48244S2; Fri, 07 Jun 2024 11:50:16 +0800 (CST) From: Bibo Mao To: Song Gao Cc: qemu-devel@nongnu.org Subject: [PATCH v3] target/loongarch/kvm: Add software breakpoint support Date: Fri, 7 Jun 2024 11:50:16 +0800 Message-Id: <20240607035016.2975799-1-maobibo@loongson.cn> X-Mailer: git-send-email 2.39.3 MIME-Version: 1.0 X-CM-TRANSID: AQAAf8AxRcV4g2JmCL0XAA--.48244S2 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, T_SCC_BODY_TEXT_LINE=-0.01 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 injected to guest kernel rather than host for normal break intruction. Here hypercall instruction with special code is used for sw breakpoint usage, and detailed instruction comes from kvm kernel with user API KVM_REG_LOONGARCH_DEBUG_INST. 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 Reviewed-by: Song Gao Tested-by: Song Gao --- v2 ... v3: 1. Refresh patch based on the latest version, succeed in compile and run since kvm uapi header files is updated. 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: dec9742cbc59415a8b83e382e7ae36395394e4bd 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 8e6e27c8bf..e1be6a6959 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 }; @@ -664,7 +665,14 @@ 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; } @@ -739,6 +747,67 @@ 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; @@ -757,6 +826,13 @@ 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);