From nobody Sat Jul 25 01:35:29 2026 Received: from ultrarisc.com (unknown [218.76.62.146]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7A8462D7393; Tue, 21 Jul 2026 02:43:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.76.62.146 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784601785; cv=none; b=Yu5rPVwmJQsFaI7bTq0g9II5yC2Gis/YVpooiHdibsb0+7nlYb1Awgw5XliaqpdcMlAvUCZNvwSW4BbNd7pDYVWtVAgg4Gd4/4yz6nHotTHst9cse9W+SmEQoWjSyoEKM1ubFH/zhdCtx5od3GAd2ZDRY1eM5QvZWOK7xvp+KOM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784601785; c=relaxed/simple; bh=m7jHSw4SqwyF7lMCiErlAMUOJBlU7JCFx/9Ps9obcSg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=mwhZYgdJ6dQ6g6SZcA18js6LHVVwbFroUgUsKHjyX6upnlasbNAq9pkDiyV4klknk51j1zr6cqOzHFbK1Nql442tbfD37Z2OV8aQpaIKJqsViyK87DgjNszGVJ63PvCuAD/SlLTVN13j+H4ewSYD/iYM/w1QHr2bQN6UmrY50v4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ultrarisc.com; spf=pass smtp.mailfrom=ultrarisc.com; dkim=pass (1024-bit key) header.d=ultrarisc.com header.i=@ultrarisc.com header.b=Peg+rs5Q; arc=none smtp.client-ip=218.76.62.146 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ultrarisc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ultrarisc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ultrarisc.com header.i=@ultrarisc.com header.b="Peg+rs5Q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ultrarisc.com; s=dkim; h=Received:From:To:Cc:Subject:Date: Message-ID:MIME-Version:Content-Transfer-Encoding; bh=m+8JTRBvx7 CawRlsSGYTxEAZAMVDmdikPetKF3KHcLA=; b=Peg+rs5QDQmMYlZ1v/lrV+5nKU vuDPvGQps8AOAm3RSHgRzR7cM6fToQNI6Vb6FG67DllnG8v9fuVPyfKtM/K4XnTZ 4dtyakybTkrol/BuYAoSx+qiC851L9WRpYlTco4TtRIiMhaZ/bwLUKiq5sabwPkU 3H9dwpN4bcE6BAKmU= Received: from ur-dp1000 (unknown [192.168.100.1]) by localhost.localdomain (Coremail) with SMTP id AQAAfwA3cUK53F5qgV8UAA--.17631S2; Tue, 21 Jul 2026 10:43:06 +0800 (CST) From: Xie Bo To: Anup Patel , Atish Patra , kvm-riscv@lists.infradead.org Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , kvm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Xie Bo Subject: [PATCH] RISC-V: KVM: Add SBI DBTR extension forwarding Date: Tue, 21 Jul 2026 10:42:36 +0800 Message-ID: <20260721024236.14761-1-xb@ultrarisc.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: AQAAfwA3cUK53F5qgV8UAA--.17631S2 X-Coremail-Antispam: 1UD129KBjvJXoWxAry5Jry3Cw47KrWfWryrCrg_yoW5ZrW3pF 4DCF1qgrWrCr40g3s7Jrs8uw1Utw15Kwn5tryDWryFqr12vry5Jr4vkry2krn8XFWrXFyS kr40gFn5uFs5J37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9l14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1j6r1xM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Jr0_Gr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4j6r 4UJwAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628v n2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCY02Avz4vE-syl42xK82IYc2Ij64vIr41l4I 8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AK xVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcV AFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8I cIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r 4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUFg4SDUUUU X-CM-SenderInfo: l0e63zxwud2x1vfou0bp/1tbiAQAOB2pdm1EAHAABso Content-Type: text/plain; charset="utf-8" The SBI headers define the Debug Triggers extension and its function IDs, but KVM does not currently allow a VMM to expose DBTR to a guest. Add DBTR to the KVM SBI extension list and forward its calls to userspace through the existing KVM_EXIT_RISCV_SBI path. Keep the extension disabled by default so that userspace must explicitly enable it through the SBI extension ONE_REG interface before running the VCPU. Signed-off-by: Xie Bo --- arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 + arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kvm/vcpu_sbi.c | 4 ++++ arch/riscv/kvm/vcpu_sbi_forward.c | 7 +++++++ 4 files changed, 13 insertions(+) diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm= /kvm_vcpu_sbi.h index c1a7e3b40..53406b02f 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -104,6 +104,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext= _rfence; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn; +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbtr; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_susp; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft; diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/as= m/kvm.h index 504e73305..047d82f05 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -221,6 +221,7 @@ enum KVM_RISCV_SBI_EXT_ID { KVM_RISCV_SBI_EXT_SUSP, KVM_RISCV_SBI_EXT_FWFT, KVM_RISCV_SBI_EXT_MPXY, + KVM_RISCV_SBI_EXT_DBTR, KVM_RISCV_SBI_EXT_MAX, }; =20 diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 46ab7b989..ed21239c5 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -70,6 +70,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ex= t[] =3D { .ext_idx =3D KVM_RISCV_SBI_EXT_DBCN, .ext_ptr =3D &vcpu_sbi_ext_dbcn, }, + { + .ext_idx =3D KVM_RISCV_SBI_EXT_DBTR, + .ext_ptr =3D &vcpu_sbi_ext_dbtr, + }, { .ext_idx =3D KVM_RISCV_SBI_EXT_SUSP, .ext_ptr =3D &vcpu_sbi_ext_susp, diff --git a/arch/riscv/kvm/vcpu_sbi_forward.c b/arch/riscv/kvm/vcpu_sbi_fo= rward.c index 5a3c75eb2..8ac31b53f 100644 --- a/arch/riscv/kvm/vcpu_sbi_forward.c +++ b/arch/riscv/kvm/vcpu_sbi_forward.c @@ -26,6 +26,13 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn = =3D { .handler =3D kvm_riscv_vcpu_sbi_forward_handler, }; =20 +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbtr =3D { + .extid_start =3D SBI_EXT_DBTR, + .extid_end =3D SBI_EXT_DBTR, + .default_disabled =3D true, + .handler =3D kvm_riscv_vcpu_sbi_forward_handler, +}; + const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_mpxy =3D { .extid_start =3D SBI_EXT_MPXY, .extid_end =3D SBI_EXT_MPXY, base-commit: b95f03f04d475aa6719d15a636ddf32222d55657 --=20 2.54.0