From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 C454C2110; Tue, 19 Aug 2025 14:27:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755613634; cv=none; b=GxxdQSfDXCjKUIOc4IeUVG5mNexbPRYJLJNnbzynkTz7ox0CiAp0RDXEvTTk9P8WktpBUKWHBYzfksf80OooYLjT2tZ+RWV76iBE7NhXnGsFR0FwjE7QewgNCnuR5jo2KCAyD1uK7ECGleQLegQ3AqcPC6sZoy1Sc0A0qPwKnp8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755613634; c=relaxed/simple; bh=yDs+kKBrbP3yEi8uWei0eMe0N9vYgihZ6nzRT6EJui0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jdEHCf//m+/GMH10/vKVf3172v5EF1JmkdaFE+8hvY5Gz9ylwTQZHBzKQBG7FOxQBdSInkK287yqV+zw3sSYteG1ZuT3qG8ij37Gwsp6yBAPt50w7nLIdq5pmSG/x3EHm7KpcLRXBSypmkduSmtQQThfpwSb/umzbBz7rWUFPKs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=T9GqhK34; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="T9GqhK34" Date: Tue, 19 Aug 2025 22:27:02 +0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1755613629; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TWvZTXUXEJL7nh5uPtT4Ud1hkvku6IV5nyuOFNoTAv0=; b=T9GqhK34sK0ikauzeNSBxRN+EiQBDKH+FGTdM+8EKZAk6f96SaUGXFbx8fWXcyBXWpZl4X 0EPRsXPggdH7pQiRg1jQTC5wQrkfVwCYUqzXVPSD80QBctEB5jeuwnpeavr0ymy91sfeaR xOyZHtsELbRedj3ZwbDihZ9DiD0AjH8= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Troy Mitchell 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, Troy Mitchell Subject: Re: [PATCH] RISC-V: KVM: Prevent HGATP_MODE_BARE passed Message-ID: References: <20250819004643.1884149-1-guoren@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250819004643.1884149-1-guoren@kernel.org> X-Migadu-Flow: FLOW_OUT On Mon, Aug 18, 2025 at 08:46:43PM -0400, guoren@kernel.org wrote: > 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) > --- > arch/riscv/kvm/gstage.c | 27 ++++++++++++++++++++++++--- > arch/riscv/kvm/main.c | 35 +++++++++++++++++------------------ > 2 files changed, 41 insertions(+), 21 deletions(-) Reviewed-by: Troy Mitchell > > 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) == HGATP_MODE_SV57X4) { > kvm_riscv_gstage_mode = HGATP_MODE_SV57X4; > kvm_riscv_gstage_pgd_levels = 5; > - goto skip_sv48x4_test; > + goto done; > } > > /* 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) == HGATP_MODE_SV48X4) { > kvm_riscv_gstage_mode = HGATP_MODE_SV48X4; > kvm_riscv_gstage_pgd_levels = 4; > + goto done; > } > -skip_sv48x4_test: > > + /* Try Sv39x4 G-stage mode */ > + csr_write(CSR_HGATP, HGATP_MODE_SV39X4 << HGATP_MODE_SHIFT); > + if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV39X4) { > + kvm_riscv_gstage_mode = HGATP_MODE_SV39X4; > + kvm_riscv_gstage_pgd_levels = 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) == HGATP_MODE_SV32X4) { > + kvm_riscv_gstage_mode = HGATP_MODE_SV32X4; > + kvm_riscv_gstage_pgd_levels = 2; > + goto done; > + } > +#endif > + > + /* KVM depends on !HGATP_MODE_OFF */ > + kvm_riscv_gstage_mode = HGATP_MODE_OFF; > + kvm_riscv_gstage_pgd_levels = 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; > > kvm_riscv_gstage_mode_detect(); > + switch (kvm_riscv_gstage_mode) { > + case HGATP_MODE_SV32X4: > + str = "Sv32x4"; > + break; > + case HGATP_MODE_SV39X4: > + str = "Sv39x4"; > + break; > + case HGATP_MODE_SV48X4: > + str = "Sv48x4"; > + break; > + case HGATP_MODE_SV57X4: > + str = "Sv57x4"; > + break; > + default: > + return -ENODEV; > + } > + kvm_info("using %s G-stage page table format\n", str); > > kvm_riscv_gstage_vmid_detect(); > > @@ -135,24 +152,6 @@ static int __init riscv_kvm_init(void) > (rc) ? slist : "no features"); > } > > - switch (kvm_riscv_gstage_mode) { > - case HGATP_MODE_SV32X4: > - str = "Sv32x4"; > - break; > - case HGATP_MODE_SV39X4: > - str = "Sv39x4"; > - break; > - case HGATP_MODE_SV48X4: > - str = "Sv48x4"; > - break; > - case HGATP_MODE_SV57X4: > - str = "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()); > > if (kvm_riscv_aia_available()) > -- > 2.40.1 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv