From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AE5732874ED; Wed, 4 Feb 2026 13:45:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770212728; cv=none; b=e2RHyHlSfNgdX4I1T4J3qKSkkFbTvexG6DT/05j2IDhs1X557oujB0cos/rfkEtG/ptLqPTb0UhfiCih5qR8H9Co2y5B0GBAeyBRaBt70MWcOTKGbeYgIxxEXLDJ5Qj1yXpQuqIXqdZ0jLP/yJQ6Bzi5NViPuoIvsqCWMbvD4NU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770212728; c=relaxed/simple; bh=K5wCrxDoRu44lWPXg8e4A9D3K+aHxqruv32sypmQUAg=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=X9T61bxFoBpFmhnk3a3af9UlIBmR3ZLX9gaTWpbAWudPFau82tvJdUQ13VuXXUD9G5mR/iZJBt96UL1lYpKwKTaBX9KYm09LAhTCy99vSf5WEZ4P5d4c2Lm+Vielw7i+gOnO95fjuuXTBOO6HsEhPp72aHU5Nky8Hd4ZPu8TkBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=aXKIyDTO; arc=none smtp.client-ip=115.124.30.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="aXKIyDTO" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1770212718; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=om1FUqBBj9rquR58NW7QTlpJTDIIM+QxVVQ3WntmFgM=; b=aXKIyDTOB1jH1bO7+h0HIy0MvmQWYxGjzeHmigOvUTh8LHAngdnzMTTRi6s88rc3Tyu5aWJNjqNQG30b4amk/JryR+2DmJKkD75qQGK217OdXLKVEzuF9LXHBxpRBWFjQXZjcLbL+OIumF5LHegTS2h0xxX2ZINw8Xh4KzX5Fb0= Received: from localhost.localdomain(mailfrom:fangyu.yu@linux.alibaba.com fp:SMTPD_---0WyXBz6r_1770212714 cluster:ay36) by smtp.aliyun-inc.com; Wed, 04 Feb 2026 21:45:16 +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, 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 v5 0/3] Support runtime configuration for per-VM's HGATP mode Date: Wed, 4 Feb 2026 21:45:04 +0800 Message-Id: <20260204134507.33912-1-fangyu.yu@linux.alibaba.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Fangyu Yu Currently, RISC-V KVM hardcodes the G-stage page table format (HGATP mode) to the maximum mode detected at boot time (e.g., SV57x4 if supported). but often such a wide GPA is unnecessary, just as a host sometimes doesn't need sv57. This patch introduces per-VM configurability of the G-stage mode via a new KVM capability: KVM_CAP_RISCV_SET_HGATP_MODE. User-space can now explicitly request a specific HGATP mode (SV39x4, SV48x4, SV57x4 or SV32x4) during VM creation. --- Changes in v5: - Use architectural HGATP.MODE encodings as the bit index for the supported-mode bitmap and for the VM-mode selection UAPI; no new UAPI mode/bit defines are introduced(per Radim). - Allow KVM_CAP_RISCV_SET_HGATP_MODE on RV32 as well(per Drew). - Link to v4: https://lore.kernel.org/linux-riscv/20260202140716.34323-1-fangyu.yu@linux.alibaba.com/ --- Changes in v4: - Extend kvm_riscv_gstage_mode_detect() to probe all HGATP.MODE values supported by the host and record them in a bitmask. - Treat unexpected pgd_levels in kvm_riscv_gstage_mode() as an internal error (e.g. WARN_ON_ONCE())(per Radim). - Move kvm_riscv_gstage_gpa_bits() and kvm_riscv_gstage_gpa_size() to header as static inline helpers(per Radim). - Drop gstage_mode_user_initialized and Remove the kvm_debug() message from KVM_CAP_RISCV_SET_HGATP_MODE(per Radim). - Link to v3: https://lore.kernel.org/linux-riscv/20260125150450.27068-1-fangyu.yu@linux.alibaba.com/ --- Changes in v3: - Reworked the patch formatting (per Drew). - Dropped kvm->arch.kvm_riscv_gstage_mode and derive HGATP.MODE from kvm_riscv_gstage_pgd_levels via a helper, avoiding redundant per-VM state(per Drew). - Removed kvm_riscv_gstage_max_mode and keep only kvm_riscv_gstage_max_pgd_levels for host capability detection(per Drew). - Other initialization and return value issues(per Drew). - Enforce that KVM_CAP_RISCV_SET_HGATP_MODE can only be enabled before any vCPUs are created by rejecting the ioctl once kvm->created_vcpus is non-zero(per Radim). - Add a memslot safety check and reject the capability unless kvm_are_all_memslots_empty(kvm) is true, ensuring the G-stage format is not changed after any memslots have been installed(per Radim). - Link to v2: https://lore.kernel.org/linux-riscv/20260105143232.76715-1-fangyu.yu@linux.alibaba.com/ Fangyu Yu (3): RISC-V: KVM: Support runtime configuration for per-VM's HGATP mode RISC-V: KVM: Detect and expose supported HGATP G-stage modes RISC-V: KVM: add KVM_CAP_RISCV_SET_HGATP_MODE Documentation/virt/kvm/api.rst | 27 ++++++++ arch/riscv/include/asm/kvm_gstage.h | 31 +++++++-- arch/riscv/include/asm/kvm_host.h | 19 ++++++ arch/riscv/kvm/gstage.c | 102 ++++++++++++++-------------- arch/riscv/kvm/main.c | 12 ++-- arch/riscv/kvm/mmu.c | 20 +++--- arch/riscv/kvm/vm.c | 21 +++++- arch/riscv/kvm/vmid.c | 3 +- include/uapi/linux/kvm.h | 1 + 9 files changed, 160 insertions(+), 76 deletions(-) -- 2.50.1