From nobody Sat Oct 4 08:03:35 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 85E7DD531; Tue, 19 Aug 2025 00:46:57 +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=1755564417; cv=none; b=KqsHjLZByJj+VKkt+jSehnimHgL8xvMT0F6t4fmSXspFcnH9UWcWzflPYQ4ONh9E7FzETUJWTTRbhiJKi9HzxmEFMBqsK2+kWtfaDpjKYJMlK3rIpM1SBsUSFNbezQfWkYmYvzzKUOTQGDlL2J3Wzx9nS1Xz9uGtKK0vAm7+CpU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755564417; c=relaxed/simple; bh=DsWrRR/JVk9NGxDPruscs5vh74AouGxQra9oUbC6csk=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=Ri+2FCML1QOXK8rH1SWvHsKfXmYmkKaBPmYb0iWGMAFiwZ2DY0bm1ARoDT0+mFcpk2Xc8KVhBeYOFTN3XFEZUrz8Lw1RdUWmT+N5NYYioHhyXTktLRmaXWxlis1+I6kETCnWJKyrxIvw7hrFA+8A7HLmvG4QxrJyxF/rNQokfR0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jrngg2QV; 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="jrngg2QV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49635C4CEEB; Tue, 19 Aug 2025 00:46:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755564417; bh=DsWrRR/JVk9NGxDPruscs5vh74AouGxQra9oUbC6csk=; h=From:To:Cc:Subject:Date:From; b=jrngg2QVHRvbWwsNWWKdi2b4rtirPpuFcxNJHZtkGhRWaGMuCRMGttAin2yqP98FL hIM8dVJa2Mn/sHI1p3ADOnVK+smt6TMQrJNUodhQXrnI2j1NnXRcB724Mi78/dWQWj Z5vlJPpbXAgBDfn/xKx5PnKFqdJKPRLPxE8M3zIgaQmB1+1aoLqcvNDYHapDpoQKZS IVdloivkEZkyZtClFh88C0QwCS3F4rG0klz/AB3CnIob55qqdYI9d970hqWfHdT6ot kDCYGT+RRQY7WYPG8wQz1qfKdE6jEG9/gI4TZn6h3FOpnmP7JkYPQJpRHavzgXtyOT 3aOnScz/HTgLw== From: guoren@kernel.org To: guoren@kernel.org, paul.walmsley@sifive.com, anup@brainfault.org, atish.patra@linux.dev, fangyu.yu@linux.alibaba.com Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org Subject: [PATCH] RISC-V: KVM: Prevent HGATP_MODE_BARE passed Date: Mon, 18 Aug 2025 20:46:43 -0400 Message-Id: <20250819004643.1884149-1-guoren@kernel.org> X-Mailer: git-send-email 2.40.1 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. Signed-off-by: Guo Ren (Alibaba DAMO Academy) Reviewed-by: Fangyu Yu Reviewed-by: Troy Mitchell --- 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