From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 27295E7DEEF for ; Mon, 2 Feb 2026 14:25:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=DEkmn1OgWe9w2P6UVkyPaVh+6hCKnxl6CNfh1iz2r3A=; b=xDbLbWjfqeMy5f ZH+ooIuIg4OAzyTMz7v++s7gdaNDRM8FuOreb599p/8VT8WJb/HVmBW2pTybLiPn2edfywtO5aIzg jMcLceEIo0MqYqaMfxAaN9f5nC6wSdBeEtaWflEAAQW5jvihwhL7jS5Kgb4nGo9nQHZE3azVR3Hag XRLyUj7qefPlvk69RTGfjWZ2p7dUWEboQLlvDHPvN8fpoWq+cULqRgtUQl7modELSc3k4/SRKLDWd 9PulUyBVzI7IBTKSytPDVKuKvO3Q5bZpapzqm6ipAzlZVoh+tnl2WRGgpCjcCQqrqVZQ8rySvHP/7 gfDuhG+r60H8ij7c3mbQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vmurU-000000055pn-404f; Mon, 02 Feb 2026 14:25:09 +0000 Received: from out199-4.us.a.mail.aliyun.com ([47.90.199.4]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vmurR-000000055oh-21wU; Mon, 02 Feb 2026 14:25:07 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1770041256; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=PAERw8ES7Sz4+PGBE81cd9YgH/6t6yHMKmA8nztW3dg=; b=uUpwPozCR1jOQd+gGwJSeOw7f4dqKNOvZZMh8z4lZ9a5+mjz1K6Psq93YeTQUxaYwf2/3KpBkARj+OdNcZsPfeFflLsSNzWV9/xGXGh/SfNN27t3vCEa+vE0VHf5LQggjXpxHQyE9qnyldqJjQb+tvCQ+nR2J39rHydRFGFTFIc= Received: from localhost.localdomain(mailfrom:fangyu.yu@linux.alibaba.com fp:SMTPD_---0WyO62Vn_1770041252 cluster:ay36) by smtp.aliyun-inc.com; Mon, 02 Feb 2026 22:07:34 +0800 From: fangyu.yu@linux.alibaba.com To: pbonzini@redhat.com, corbet@lwn.net, anup@brainfault.org, atish.patra@linux.dev, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr Cc: guoren@kernel.org, ajones@ventanamicro.com, rkrcmar@ventanamicro.com, radim.krcmar@oss.qualcomm.com, andrew.jones@oss.qualcomm.com, linux-doc@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Fangyu Yu Subject: [PATCH v4 2/4] RISC-V: KVM: Detect and expose supported HGATP G-stage modes Date: Mon, 2 Feb 2026 22:07:14 +0800 Message-Id: <20260202140716.34323-3-fangyu.yu@linux.alibaba.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20260202140716.34323-1-fangyu.yu@linux.alibaba.com> References: <20260202140716.34323-1-fangyu.yu@linux.alibaba.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260202_062505_852705_976BCA88 X-CRM114-Status: GOOD ( 10.35 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Fangyu Yu Extend kvm_riscv_gstage_mode_detect() to probe all HGATP.MODE values supported by the host and record them in a bitmask. Keep tracking the maximum supported G-stage page table level for existing internal users. Also provide lightweight helpers to retrieve the supported-mode bitmask and validate a requested HGATP.MODE against it. Signed-off-by: Fangyu Yu --- arch/riscv/include/asm/kvm_gstage.h | 37 +++++++++++++++++++++++++++ arch/riscv/kvm/gstage.c | 39 ++++++++++++++++------------- 2 files changed, 58 insertions(+), 18 deletions(-) diff --git a/arch/riscv/include/asm/kvm_gstage.h b/arch/riscv/include/asm/kvm_gstage.h index b12605fbca44..c0c5a8b99056 100644 --- a/arch/riscv/include/asm/kvm_gstage.h +++ b/arch/riscv/include/asm/kvm_gstage.h @@ -30,6 +30,7 @@ struct kvm_gstage_mapping { #endif extern unsigned long kvm_riscv_gstage_max_pgd_levels; +extern u32 kvm_riscv_gstage_mode_mask; #define kvm_riscv_gstage_pgd_xbits 2 #define kvm_riscv_gstage_pgd_size (1UL << (HGATP_PAGE_SHIFT + kvm_riscv_gstage_pgd_xbits)) @@ -75,4 +76,40 @@ void kvm_riscv_gstage_wp_range(struct kvm_gstage *gstage, gpa_t start, gpa_t end void kvm_riscv_gstage_mode_detect(void); +enum kvm_riscv_hgatp_mode_bit { + HGATP_MODE_SV39X4_BIT = 0, + HGATP_MODE_SV48X4_BIT = 1, + HGATP_MODE_SV57X4_BIT = 2, +}; + +static inline u32 kvm_riscv_get_hgatp_mode_mask(void) +{ + return kvm_riscv_gstage_mode_mask; +} + +static inline bool kvm_riscv_hgatp_mode_is_valid(unsigned long mode) +{ +#ifdef CONFIG_64BIT + u32 bit; + + switch (mode) { + case HGATP_MODE_SV39X4: + bit = HGATP_MODE_SV39X4_BIT; + break; + case HGATP_MODE_SV48X4: + bit = HGATP_MODE_SV48X4_BIT; + break; + case HGATP_MODE_SV57X4: + bit = HGATP_MODE_SV57X4_BIT; + break; + default: + return false; + } + + return kvm_riscv_gstage_mode_mask & BIT(bit); +#else + return false; +#endif +} + #endif diff --git a/arch/riscv/kvm/gstage.c b/arch/riscv/kvm/gstage.c index 2d0045f502d1..edbabdac57d8 100644 --- a/arch/riscv/kvm/gstage.c +++ b/arch/riscv/kvm/gstage.c @@ -16,6 +16,8 @@ unsigned long kvm_riscv_gstage_max_pgd_levels __ro_after_init = 3; #else unsigned long kvm_riscv_gstage_max_pgd_levels __ro_after_init = 2; #endif +/* Bitmask of supported HGATP.MODE (see HGATP_MODE_*_BIT). */ +u32 kvm_riscv_gstage_mode_mask __ro_after_init; #define gstage_pte_leaf(__ptep) \ (pte_val(*(__ptep)) & (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)) @@ -315,42 +317,43 @@ void kvm_riscv_gstage_wp_range(struct kvm_gstage *gstage, gpa_t start, gpa_t end } } +static bool __init kvm_riscv_hgatp_mode_supported(unsigned long mode) +{ + csr_write(CSR_HGATP, mode << HGATP_MODE_SHIFT); + return ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == mode); +} + void __init kvm_riscv_gstage_mode_detect(void) { + kvm_riscv_gstage_mode_mask = 0; + kvm_riscv_gstage_max_pgd_levels = 0; + #ifdef CONFIG_64BIT - /* Try Sv57x4 G-stage mode */ - csr_write(CSR_HGATP, HGATP_MODE_SV57X4 << HGATP_MODE_SHIFT); - if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV57X4) { - kvm_riscv_gstage_max_pgd_levels = 5; - goto done; + /* Try Sv39x4 G-stage mode */ + if (kvm_riscv_hgatp_mode_supported(HGATP_MODE_SV39X4)) { + kvm_riscv_gstage_mode_mask |= BIT(HGATP_MODE_SV39X4_BIT); + kvm_riscv_gstage_max_pgd_levels = 3; } /* Try Sv48x4 G-stage mode */ - csr_write(CSR_HGATP, HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT); - if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV48X4) { + if (kvm_riscv_hgatp_mode_supported(HGATP_MODE_SV48X4)) { + kvm_riscv_gstage_mode_mask |= BIT(HGATP_MODE_SV48X4_BIT); kvm_riscv_gstage_max_pgd_levels = 4; - goto done; } - /* 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_max_pgd_levels = 3; - goto done; + /* Try Sv57x4 G-stage mode */ + if (kvm_riscv_hgatp_mode_supported(HGATP_MODE_SV57X4)) { + kvm_riscv_gstage_mode_mask |= BIT(HGATP_MODE_SV57X4_BIT); + kvm_riscv_gstage_max_pgd_levels = 5; } #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_max_pgd_levels = 2; - goto done; } #endif - /* KVM depends on !HGATP_MODE_OFF */ - kvm_riscv_gstage_max_pgd_levels = 0; - -done: csr_write(CSR_HGATP, 0); kvm_riscv_local_hfence_gvma_all(); } -- 2.50.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv