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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F12CC0502A for ; Tue, 30 Aug 2022 19:42:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231659AbiH3Tmz (ORCPT ); Tue, 30 Aug 2022 15:42:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231555AbiH3Tmi (ORCPT ); Tue, 30 Aug 2022 15:42:38 -0400 Received: from out1.migadu.com (out1.migadu.com [IPv6:2001:41d0:2:863f::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 598047B7AF; Tue, 30 Aug 2022 12:42:24 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1661888542; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PAa+cBkl9mtwNYK8/w+PcWpN4aBBuzKZQpA5735hA3U=; b=ZLs5MEMDu72sPbf1oddAbPXFBK5HqyrH0LLuSMgJABWcVJhbffI94ChKh6fxlG4PUKb7Vt fp76TAzFIbxRDAKaCkX+hrkh4G3NnP0ojf+1rETVa0eO6qJqWT0Ozz+ovLennkecVRUXjy TzWk0l+KpUzy6uyX60KuJjkrZ/YIBkM= From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Quentin Perret , Ricardo Koller , Reiji Watanabe , David Matlack , Ben Gardon , Paolo Bonzini , Gavin Shan , Peter Xu , Sean Christopherson , Oliver Upton Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 08/14] KVM: arm64: Protect page table traversal with RCU Date: Tue, 30 Aug 2022 19:41:26 +0000 Message-Id: <20220830194132.962932-9-oliver.upton@linux.dev> In-Reply-To: <20220830194132.962932-1-oliver.upton@linux.dev> References: <20220830194132.962932-1-oliver.upton@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The use of RCU is necessary to change the paging structures in parallel. Acquire and release an RCU read lock when traversing the page tables. Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_pgtable.h | 19 ++++++++++++++++++- arch/arm64/kvm/hyp/pgtable.c | 7 ++++++- 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 78fbb7be1af6..7d2de0a98ccb 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -578,9 +578,26 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte); */ enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte); +#if defined(__KVM_NVHE_HYPERVISOR___) + +static inline void kvm_pgtable_walk_begin(void) {} +static inline void kvm_pgtable_walk_end(void) {} + +#define kvm_dereference_ptep rcu_dereference_raw + +#else /* !defined(__KVM_NVHE_HYPERVISOR__) */ + +#define kvm_pgtable_walk_begin rcu_read_lock +#define kvm_pgtable_walk_end rcu_read_unlock +#define kvm_dereference_ptep rcu_dereference + +#endif /* defined(__KVM_NVHE_HYPERVISOR__) */ + static inline kvm_pte_t kvm_pte_read(kvm_pte_t *ptep) { - return READ_ONCE(*ptep); + kvm_pte_t __rcu *p = (kvm_pte_t __rcu *)ptep; + + return READ_ONCE(*kvm_dereference_ptep(p)); } #endif /* __ARM64_KVM_PGTABLE_H__ */ diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index f911509e6512..215a14c434ed 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -284,8 +284,13 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, .end = PAGE_ALIGN(walk_data.addr + size), .walker = walker, }; + int r; - return _kvm_pgtable_walk(&walk_data); + kvm_pgtable_walk_begin(); + r = _kvm_pgtable_walk(&walk_data); + kvm_pgtable_walk_end(); + + return r; } struct leaf_walk_data { -- 2.37.2.672.g94769d06f0-goog