From nobody Sat Feb 7 08:28:35 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B55618C933; Thu, 21 Aug 2025 03:17:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755746264; cv=none; b=cMoDGTAokycwzC50Fo/CoiqRRIkxCfWTCHyU66mOiXlvnaWF9wypTmB4vKP802ledlwOajNgWHgjH/A05QyWcNiWClePQaP4waaqYLDV4OxlbnM0Coicd5rmc7sfOkQtdX7Gz/KwRfjR69E3UPLg5V+6HwAwdi/w59ecG1EMWxY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755746264; c=relaxed/simple; bh=SjKIvgxvILxvhlxc+qvjcKbL1gYIOzuL2gDprUk8RXw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=lcQHr3gn/E4O07Q6eHDYSa3n0ldpIfwk3fpkwmirsJ41wyGJaIYWPpArHofqcIUidjrXiOzld8BimVs3KAWw6NF0Jv+jeZgxPbsV6S2GuYD1G6n4yeqH1iFgGLSOMQ77ajXF2ci+yGSo2ZxtXt1Ub0yWrmIClgm7vnveqD0oAJA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=F5Wz89RN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="F5Wz89RN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1119C113CF; Thu, 21 Aug 2025 03:17:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755746264; bh=SjKIvgxvILxvhlxc+qvjcKbL1gYIOzuL2gDprUk8RXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F5Wz89RNFpDq21laO5HMZNdPCo2Fep3GFnnr/itXr2wAkW5inDAOjmOQgxqoIfLvl Qr+pA84u66KkEzkjpzxaEgOZmj1iyD1VwbfixXaIKOjf+XRUqgFJ8UyyfDXNM8RE3y TmugCQoXOWa6gkdn66zOYEQWfIVc4zH9i6g+GWQRybQCFEM3AfgkqYasCpe08mo1oN BxfASjSVAS6YXwwQUIb27yC7/EwxIX0N0IBEAiMr/2Q/k6MUv/byvFKYHClwRB3eae Y7Ei3+3SGET/+spA0p9kdJuaBHueHH3MvSgXLgtIodU253DJ8B/8Ts0Bma4n7/O9fy Jvgm7Uf6IrU3w== From: guoren@kernel.org To: guoren@kernel.org, troy.mitchell@linux.dev Cc: alex@ghiti.fr, anup@brainfault.org, aou@eecs.berkeley.edu, atish.patra@linux.dev, fangyu.yu@linux.alibaba.com, guoren@linux.alibaba.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, palmer@dabbelt.com, paul.walmsley@sifive.com, Nutty Liu , Troy Mitchell Subject: [PATCH V4 1/3] RISC-V: KVM: Write hgatp register with valid mode bits Date: Wed, 20 Aug 2025 23:17:16 -0400 Message-Id: <20250821031719.2366017-2-guoren@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20250821031719.2366017-1-guoren@kernel.org> References: <20250821031719.2366017-1-guoren@kernel.org> 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 Content-Type: text/plain; charset="utf-8" From: Fangyu Yu According to the RISC-V Privileged Architecture Spec, when MODE=3DBare is selected,software must write zero to the remaining fields of hgatp. We have detected the valid mode supported by the HW before, So using a valid mode to detect how many vmid bits are supported. Fixes: fd7bb4a251df ("RISC-V: KVM: Implement VMID allocator") Reviewed-by: Nutty Liu Reviewed-by: Troy Mitchell Reviewed-by: Guo Ren (Alibaba DAMO Academy) Signed-off-by: Fangyu Yu Signed-off-by: Guo Ren (Alibaba DAMO Academy) --- arch/riscv/kvm/vmid.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c index 3b426c800480..5f33625f4070 100644 --- a/arch/riscv/kvm/vmid.c +++ b/arch/riscv/kvm/vmid.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include =20 @@ -28,7 +29,7 @@ void __init kvm_riscv_gstage_vmid_detect(void) =20 /* Figure-out number of VMID bits in HW */ old =3D csr_read(CSR_HGATP); - csr_write(CSR_HGATP, old | HGATP_VMID); + csr_write(CSR_HGATP, (kvm_riscv_gstage_mode << HGATP_MODE_SHIFT) | HGATP_= VMID); vmid_bits =3D csr_read(CSR_HGATP); vmid_bits =3D (vmid_bits & HGATP_VMID) >> HGATP_VMID_SHIFT; vmid_bits =3D fls_long(vmid_bits); --=20 2.40.1