From nobody Sat Oct 4 03:17:22 2025 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 From nobody Sat Oct 4 03:17:22 2025 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 0E40518C933; Thu, 21 Aug 2025 03:17:49 +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=1755746270; cv=none; b=E+64WPCAdwY+l8t6oaFcx96UjxjjPErvjFD9pbuQ8xS3WV9GqL/Ci62ui381YLo7Egdea/augRzm07dZwSyDp/vZl1vhSbaat2cUeJoBJ/ZnK7ArzWQXfZIRLUFkW/zJKQ3z6vG07OHeQ4fdYnSoQamAVKr/Of9LdhIZKhCQI2A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755746270; c=relaxed/simple; bh=h+RF8Zb0d9oJ8hZkMq/D3wvDV9FwApYP4YjX6BOlwV0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=jWN/pyXwmIlBgWge4CJHNXxG3Xlaif6OARpXiCwIKYNVI0UUwkjdwMNn1CrQokBh52S2fA+C+SZwlGBOrg+zd/LuDazxpK03Kb54BeD77UHV3iRYxyeM/c/Kee7z65ttvnxLGdHc2YkWB2SrKxddyyTbj1s6Wx6p2N2hr4Xerjk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RSGJq1DP; 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="RSGJq1DP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DEC9C4CEF4; Thu, 21 Aug 2025 03:17:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755746269; bh=h+RF8Zb0d9oJ8hZkMq/D3wvDV9FwApYP4YjX6BOlwV0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RSGJq1DPysGgIf+Lr/1513mNXeTyr7qdgoGdnWxlqycHWI1Gn+d7cX/ZgRfWAONco ZkVGg+aiH9OHwm5T9ph0bNE8BaRYfpN0U4a/E9YGtoZpda05aOtiEPM0Cb2ziq0do2 +lA9oPDwkbUCOhBbBb0lIA+v8Nf6Pd1rRJxS9s6Ur1KrzEZmT3ua+BTknKhaokBYoV 4FVfXrvAbmhDjpo0UfcsQzQOo+Q2r0zpRUwOANSzriB/1T5vE8XqtruRQ2uXWi+ybJ 2zkw2MV7OK0tkfGm6C3hqb7h2futgD97togXhjc13T9DT1sOlOtgkt3HmBezphki4n 8s8bZg3T+GkXQ== 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 Subject: [PATCH V4 2/3] RISC-V: KVM: Remove unnecessary HGATP csr_read Date: Wed, 20 Aug 2025 23:17:17 -0400 Message-Id: <20250821031719.2366017-3-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: "Guo Ren (Alibaba DAMO Academy)" The HGATP has been set to zero in gstage_mode_detect(), so there is no need to save the old context. Unify the code convention with gstage_mode_detect(). Signed-off-by: Fangyu Yu Signed-off-by: Guo Ren (Alibaba DAMO Academy) --- arch/riscv/kvm/vmid.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c index 5f33625f4070..abb1c2bf2542 100644 --- a/arch/riscv/kvm/vmid.c +++ b/arch/riscv/kvm/vmid.c @@ -25,15 +25,12 @@ static DEFINE_SPINLOCK(vmid_lock); =20 void __init kvm_riscv_gstage_vmid_detect(void) { - unsigned long old; - /* Figure-out number of VMID bits in HW */ - old =3D csr_read(CSR_HGATP); 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); - csr_write(CSR_HGATP, old); + csr_write(CSR_HGATP, 0); =20 /* We polluted local TLB so flush all guest TLB */ kvm_riscv_local_hfence_gvma_all(); --=20 2.40.1 From nobody Sat Oct 4 03:17:22 2025 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 9C08F18C933; Thu, 21 Aug 2025 03:17:54 +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=1755746274; cv=none; b=JC3Gc10uLvdqxHL5flIvTfDlQAflUxiY2wXPwpC7xHdfmfBg8DQS+RmJEQYivkiU21cfM0VAqqYW8adWWSXD1ZIppQsB3s62L0G0+ltUmnVP1qo4Xe9CiGZ1x9JgX4uEQQ890YN7ziZWHdVExG+z1RjoI//UNtpx5iLN9e3QXFI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755746274; c=relaxed/simple; bh=DMRWjGxN262TTh3G5XEfX36BOwhJZxZpsyMaejs1xjc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=mXrmADRaZe0vWsnYTkPtL8wr5T4JqCkUDYpO0a3tpA8MgUi9OwcJ5Nt+YfUpztKQYHAovwmv9mtW5ZHS4mVcgvZELT8jOefanHvHAkcnNwDbpUdYDUPiRDkjwhuGM/EAk4ajJbc09ceFkbxxIQmSwqu1lNPjvGeo2jBqyS2+FEo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jjIATB4z; 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="jjIATB4z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E05C2C113CF; Thu, 21 Aug 2025 03:17:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755746274; bh=DMRWjGxN262TTh3G5XEfX36BOwhJZxZpsyMaejs1xjc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jjIATB4zD7fodr7HIVXX5acF/oLmA+F+rCzD6d36kDPuMtRAx3DH/T3oGRXgda4ON 4ADF4lBAPeSYUsiu7/1iv10poNdPIM2sc9SDTdpRV/lBsbTycsWJ9RBqZWks8e3mHk 39gcyPtpbiEd3fyMKBz46Fd4xy/osqSbGn3D8DiPF8myJ0ve3UkJ4fb75aXEkSgHAd IcsH0hU/RxeAsdIa4ZLNw6CsoKy/EdOxykwvGSJq9hLzjtztpQFn2mjS/cC9TVBVVO scyjqOL4BrYmZRGZtmfB8H/4HhPm2pkUCwEJuq/B+H/axgGd/ImyrYtMiPzE4bDfzX jYxrOalEVsyIQ== 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 Subject: [PATCH V4 3/3] RISC-V: KVM: Prevent HGATP_MODE_BARE passed Date: Wed, 20 Aug 2025 23:17:18 -0400 Message-Id: <20250821031719.2366017-4-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: "Guo Ren (Alibaba DAMO Academy)" urrent kvm_riscv_gstage_mode_detect() assumes H-extension must have HGATP_MODE_SV39X4/SV32X4 at least, but the spec allows H-extension with HGATP_MODE_BARE alone. The KVM depends on !HGATP_MODE_BARE at least, so enhance the gstage-mode-detect to block HGATP_MODE_BARE. Move gstage-mode-check closer to gstage-mode-detect to prevent unnecessary init. Reviewed-by: Troy Mitchell Reviewed-by: Nutty Liu Signed-off-by: Guo Ren (Alibaba DAMO Academy) --- arch/riscv/kvm/gstage.c | 27 ++++++++++++++++++++++++--- arch/riscv/kvm/main.c | 35 +++++++++++++++++------------------ 2 files changed, 41 insertions(+), 21 deletions(-) diff --git a/arch/riscv/kvm/gstage.c b/arch/riscv/kvm/gstage.c index 24c270d6d0e2..b67d60d722c2 100644 --- a/arch/riscv/kvm/gstage.c +++ b/arch/riscv/kvm/gstage.c @@ -321,7 +321,7 @@ void __init kvm_riscv_gstage_mode_detect(void) if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) =3D=3D HGATP_MODE_SV57X4) { kvm_riscv_gstage_mode =3D HGATP_MODE_SV57X4; kvm_riscv_gstage_pgd_levels =3D 5; - goto skip_sv48x4_test; + goto done; } =20 /* Try Sv48x4 G-stage mode */ @@ -329,10 +329,31 @@ void __init kvm_riscv_gstage_mode_detect(void) if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) =3D=3D HGATP_MODE_SV48X4) { kvm_riscv_gstage_mode =3D HGATP_MODE_SV48X4; kvm_riscv_gstage_pgd_levels =3D 4; + goto done; } -skip_sv48x4_test: =20 + /* Try Sv39x4 G-stage mode */ + csr_write(CSR_HGATP, HGATP_MODE_SV39X4 << HGATP_MODE_SHIFT); + if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) =3D=3D HGATP_MODE_SV39X4) { + kvm_riscv_gstage_mode =3D HGATP_MODE_SV39X4; + kvm_riscv_gstage_pgd_levels =3D 3; + goto done; + } +#else /* CONFIG_32BIT */ + /* Try Sv32x4 G-stage mode */ + csr_write(CSR_HGATP, HGATP_MODE_SV32X4 << HGATP_MODE_SHIFT); + if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) =3D=3D HGATP_MODE_SV32X4) { + kvm_riscv_gstage_mode =3D HGATP_MODE_SV32X4; + kvm_riscv_gstage_pgd_levels =3D 2; + goto done; + } +#endif + + /* KVM depends on !HGATP_MODE_OFF */ + kvm_riscv_gstage_mode =3D HGATP_MODE_OFF; + kvm_riscv_gstage_pgd_levels =3D 0; + +done: csr_write(CSR_HGATP, 0); kvm_riscv_local_hfence_gvma_all(); -#endif } diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c index 67c876de74ef..8ee7aaa74ddc 100644 --- a/arch/riscv/kvm/main.c +++ b/arch/riscv/kvm/main.c @@ -93,6 +93,23 @@ static int __init riscv_kvm_init(void) return rc; =20 kvm_riscv_gstage_mode_detect(); + switch (kvm_riscv_gstage_mode) { + case HGATP_MODE_SV32X4: + str =3D "Sv32x4"; + break; + case HGATP_MODE_SV39X4: + str =3D "Sv39x4"; + break; + case HGATP_MODE_SV48X4: + str =3D "Sv48x4"; + break; + case HGATP_MODE_SV57X4: + str =3D "Sv57x4"; + break; + default: + return -ENODEV; + } + kvm_info("using %s G-stage page table format\n", str); =20 kvm_riscv_gstage_vmid_detect(); =20 @@ -135,24 +152,6 @@ static int __init riscv_kvm_init(void) (rc) ? slist : "no features"); } =20 - switch (kvm_riscv_gstage_mode) { - case HGATP_MODE_SV32X4: - str =3D "Sv32x4"; - break; - case HGATP_MODE_SV39X4: - str =3D "Sv39x4"; - break; - case HGATP_MODE_SV48X4: - str =3D "Sv48x4"; - break; - case HGATP_MODE_SV57X4: - str =3D "Sv57x4"; - break; - default: - return -ENODEV; - } - kvm_info("using %s G-stage page table format\n", str); - kvm_info("VMID %ld bits available\n", kvm_riscv_gstage_vmid_bits()); =20 if (kvm_riscv_aia_available()) --=20 2.40.1