From nobody Sat Oct 4 00:26:58 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 6B4972D6405; Thu, 21 Aug 2025 14:26:08 +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=1755786368; cv=none; b=k/qBwhoI4mKueNrXp6f1AFfNmRuTnuYCy0BTcpNS9ta8jKdo2s2HkTN6e5lwGAUmaNRbiAxqJG1A/qWqYAu986kGbZ2u4IKYJ5We5l2pSMfjx3xrUo6L18nY08aoamoqYgvVroHlnpICjCyGl4wpW0p7YmooFkxwIEjEpFs4E2Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755786368; c=relaxed/simple; bh=SjKIvgxvILxvhlxc+qvjcKbL1gYIOzuL2gDprUk8RXw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=n0T4tDSmESOD4hMI7QYg97g9isX7ozyeg4ram6qb5H2PYS9/O41SrHiu57yN7ntoLAkqdkSS0ioqRlSKQ2Z6ulqlR1b1dwaP7cWMYVK9Xx1wphmcSgpFXF74lIGHbyt5qYpRze92uJGUmG1vGZcupB1VOhbBwWxTtFhrbxTjwpc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eO4X4D+e; 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="eO4X4D+e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A355C4CEF4; Thu, 21 Aug 2025 14:26:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755786368; bh=SjKIvgxvILxvhlxc+qvjcKbL1gYIOzuL2gDprUk8RXw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eO4X4D+eJ5MIGDyLmCAoKu949pGua8tVh4BV2PyxZC+P8SacIeWNDxI2Vr5SCyFoX zy+x6Ka7BoBc1yA8X5kn0LPDzC2S8wadzowzTntqQ+vJw0yQWs6GkhJAkGJzNJ1VW0 Ly65kHNc/RhvM8K23X9Q68UCIAK51yI3QD7fzcUpECZsu8rs1r7feFufMgOkatcSqm yPcdTNvNRTTqb/NericCHeFH+vunh86qRgfYL+zkX0yJrD4MMwnHSNRWdqbYMHSurf 7PDsLy/iu64gaLE2x1ZMpRpnnS/b2U4/JtVCFfDf4t7jX1jwW8+pJqnVb92Iv21x+w zAlnWQKzeILTA== 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 RESEND 1/3] RISC-V: KVM: Write hgatp register with valid mode bits Date: Thu, 21 Aug 2025 10:25:40 -0400 Message-Id: <20250821142542.2472079-2-guoren@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20250821142542.2472079-1-guoren@kernel.org> References: <20250821142542.2472079-1-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 00:26:58 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 0BA032D6E5D; Thu, 21 Aug 2025 14:26:12 +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=1755786373; cv=none; b=rDzjlfZgtSt/fl+d9Tr+QeLG7dbFd7orWv2QGCMyqU5pO7wjA11P0OHQ+8IGFdW5RvMo1mcyw4rNSI2ro3z3svNmJPiHOMf/oHaQDhG2i/WrsWjoYv/hewBSmTzWlvgwC+JufmjNMPiUm1OLqvi2Re/wNoUf2Ro8FfsOWE83hyw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755786373; c=relaxed/simple; bh=G0YrLOlqNEkhmNDKqjNXIej+ao+iP0qZxWm/nWbxgcU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=QF5PaYhXVtL8/Odfjm0qcLN8OxSBCghdhdxyxrou0zI8F7q5WHAsA6R2u+863xkFURlR1Y+lyiuEd0qGPCKV+iimosQxKNVGIA4tQv26yEgiMxalxUIJzp+cbV55Xhj8PdGKi9o/zXR5KqegWvMgmcP9672D/wCrXWCU4IazRwg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nIUwo+87; 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="nIUwo+87" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78E13C4CEEB; Thu, 21 Aug 2025 14:26:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755786372; bh=G0YrLOlqNEkhmNDKqjNXIej+ao+iP0qZxWm/nWbxgcU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nIUwo+87Ry/oXZ6mg9Fw4HZ0MMFxJkXAarXgjf1itGfDNVkddF4Mp9uqfxoFzfwwq dKkxZPxRYY1b8fD4Gzfy77M8ZwRGzu1RRdhCgLkhFVCyRl9G71eTogt/T+i5tI71u+ BllOOUXWaAO6HLOOnHNhwvJlDGq/Rmr3zM/Qy4lQu2tGIUSeYmZSvD2I3ubrSiHccA h5aSW27p/WEpPX2u1iVBmgKU7a0nHp6CD+jOJXNj/XTA4RLvZAdRNMlxXbmUNEvnWf gI32iy8/42hgb5rRDxJhwI6k52FpdkimxQJmeV9X99ERICX2upoWuiSF28m4VDYneg VKarGoW2PNQRA== 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 RESEND 2/3] RISC-V: KVM: Remove unnecessary HGATP csr_read Date: Thu, 21 Aug 2025 10:25:41 -0400 Message-Id: <20250821142542.2472079-3-guoren@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20250821142542.2472079-1-guoren@kernel.org> References: <20250821142542.2472079-1-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(). Reviewed-by: Fangyu Yu 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 00:26:58 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 2BFA81DE8B2; Thu, 21 Aug 2025 14:26:17 +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=1755786377; cv=none; b=ZRN1LWQ28yk5Wbvdfy2GBSvEUN7r+L1oNQFmyRQUsNRdFqYEnYTjf/ZEbakE8NjZ193vDEHUmWdy9WmKjPnmU4MkkpB5ZwFT+k/VBsIkjcOZqbp+G4FfgMFAWkAJNUR4NjOVzeL/ETcFsJAY4u0Di3kMfK7D6Oj3D5oLcTvtWhY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755786377; c=relaxed/simple; bh=DMRWjGxN262TTh3G5XEfX36BOwhJZxZpsyMaejs1xjc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=QbxZz6MtWK56s2lS98i2wYuO/n9FMywNOoE534QJ6J3F9Mon9dc/UnxyY0kSfcU3LaoSHdT4gdzuLjd/Z2uAEBwbP2TWnZFw4hVfL1Z87JkO62KOsXqASIrd1CDGAgRqgEIwpaDE12U2k1KmjhmnIiG4O2e5MaNK/xN0SbQW5ew= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G73bsXs7; 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="G73bsXs7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 731B3C4CEEB; Thu, 21 Aug 2025 14:26:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755786377; bh=DMRWjGxN262TTh3G5XEfX36BOwhJZxZpsyMaejs1xjc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G73bsXs7hd6bavivDbDbKhs7p+62Ff4SrQ/jPxYewju79uoySLhmxkH+pdQZ/Ceyj r2Vk9curcO7fNu6BpgeLvrz9J2V0L4vODztLkCsOeG11FQiXJYhINEwTtdVclPPVhW DbDQ018IYJzoc/GXZedNDbBUuear7VwvMLQ1IjvxpeKGwl7i1OI2XQfIy/JzvpRDBv iBZqv9ZzouDtAZQgMGbcU7qmi0XB+WXR+2Q3YaRg5tM0O+TNex5Rk+IwikjU6SUfc4 1MVVA4qw8cWs7laRu0ivQWY4PANZ8ftoIM9gmxam3in9qV9WGmgGE5vWfh2N0uD+8i 1vQxucfj4vQZQ== 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 RESEND 3/3] RISC-V: KVM: Prevent HGATP_MODE_BARE passed Date: Thu, 21 Aug 2025 10:25:42 -0400 Message-Id: <20250821142542.2472079-4-guoren@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20250821142542.2472079-1-guoren@kernel.org> References: <20250821142542.2472079-1-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