From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 37A8F606D80F for ; Wed, 4 Nov 2026 12:45:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=vtteTcxp; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=QylGKXh7 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=AOH3Su8TZJSoK9UPHpeuwIAfG494iGEabcz+aB8amog=; b=vtteTcxpdtLsT6 efHmvZXeuqz8zEIN0bsKOVc9gfO+M70djU6jb5B/iW75EMmBiZhvpHleMXRW180mkIUEUD9ffFf+J KkN6nZ6wGmHncP+t79xpjdByniusvxHY6QoNOxn7mGIL8ofRPmqRPFlEDzYJieCl9JVUbQmRNhZ1J sj8RVawo8/DYrei+Nu1ADV2nPkfZh8+zv4o5JiSywkkj+BSU+megsZLBhmsqJXe6Vmkjs8sYkPmt/ tP9p+efN9NlaJ33QCpNqIdD1EX+e/SxJ4PicdoRkiiMDoumLg0REGkDfhoe1raORU2fEo9XU0RZYJ dNhXiEh2+5gbyeYlmbCw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOaMO-00000005MnL-0w2A; Wed, 04 Nov 2026 12:45:00 +0000 Received: from out-148.mta1.migadu.com ([95.215.58.148] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOaMI-00000005Mkk-43RS for linux-arm-kernel@lists.infradead.org; Wed, 04 Nov 2026 12:44:58 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=MxRHPNAABvoNmLp9OTJVcSokfGwwqtsziGyV/1PffQk=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793796293; v=1; x=1794401093; b=QylGKXh7uruaLMMEMoxZ64DR/6WRHSeRr9NW0qyTOuBE10TrPTF2dySKAaKqBH8OXK9T5lgW JuVyld+yb+3T7O/1JiDm1nj1jAxQHg1Yx+8Ir/sF6OYZ8nchI3kbHqN0Ed71GeYVXqwp3PGSJvU Px8botegn2j4AGcqtjnNkmgM= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id fec1c38f76d92ee4; Wed, 04 Nov 2026 12:44:53 +0000 X-Mizu-Trace-ID: fec1c38f76d92ee4 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Raghavendra Rao Ananta , Vincent Donnefort , Fuad Tabba Subject: [PATCH v2 1/2] KVM: arm64: Resume stage-2 teardown where the walk stopped Date: Wed, 4 Nov 2026 12:44:50 +0000 Message-ID: <20261104124451.2148724-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261104124451.2148724-1-fuad.tabba@linux.dev> References: <20261104124451.2148724-1-fuad.tabba@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261104_044456_928511_F83EDBC8 X-CRM114-Status: GOOD ( 15.44 ) X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Since commit 4ddfab5436b6 ("KVM: arm64: Reschedule as needed when destroying the stage-2 page-tables"), kvm_stage2_destroy() walks the IPA space one block-sized chunk at a time. The walker steps over an invalid entry in one go, but the next walk starts at the following chunk, so an invalid entry larger than a chunk is visited once for every chunk it covers. Destroying a VM with a 52-bit IPA then takes 2^27 walks with 16K pages (2^22 with 4K), however little it maps. Have kvm_pgtable_stage2_destroy_range() return the address its walk reached, which kvm_pgtable_walk() doesn't expose, and resume from there. pkvm_pgtable_stage2_destroy_range() returns the end of its range, and EL2's kvm_pgtable_stage2_destroy() ignores the value. Suggested-by: Suzuki K Poulose Suggested-by: Oliver Upton Signed-off-by: Fuad Tabba --- arch/arm64/include/asm/kvm_pgtable.h | 8 ++++++-- arch/arm64/include/asm/kvm_pkvm.h | 4 ++-- arch/arm64/kvm/hyp/pgtable.c | 15 ++++++++++++--- arch/arm64/kvm/mmu.c | 4 ++-- arch/arm64/kvm/pkvm.c | 8 +++++--- 5 files changed, 27 insertions(+), 12 deletions(-) diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 1c9c57cd6ae40..20b988e99e074 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -599,9 +599,13 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt); * * The page-table is assumed to be unreachable by any hardware walkers prior * to freeing and therefore no TLB invalidation is performed. + * + * Return: the address the walk reached, which can be past @addr + @size + * when the range ends within a block or an invalid entry, or @addr + @size + * if the walk fails. */ -void kvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, - u64 addr, u64 size); +u64 kvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, + u64 addr, u64 size); /** * kvm_pgtable_stage2_destroy_pgd() - Destroy the PGD of guest stage-2 page-table. diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index fd042d2b54624..731632aa24520 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -349,8 +349,8 @@ int __pkvm_handle_smccc_req(struct arm_smccc_res *res); int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, struct kvm_pgtable_mm_ops *mm_ops); -void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, - u64 addr, u64 size); +u64 pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, + u64 addr, u64 size); void pkvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt); int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys, enum kvm_pgtable_prot prot, void *mc, diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 9c83837b184d3..6bb1c0beb4dcc 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1653,16 +1653,25 @@ static int stage2_free_walker(const struct kvm_pgtable_visit_ctx *ctx, } } -void kvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, - u64 addr, u64 size) +u64 kvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, + u64 addr, u64 size) { struct kvm_pgtable_walker walker = { .cb = stage2_free_walker, .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, }; + struct kvm_pgtable_walk_data data = { + .walker = &walker, + .start = addr, + .addr = addr, + .end = addr + size, + }; - WARN_ON(kvm_pgtable_walk(pgt, addr, size, &walker)); + if (WARN_ON(_kvm_pgtable_walk(pgt, &data))) + return addr + size; + + return data.addr; } void kvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 1db10d8d6db73..4f1adadeffb8b 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1011,8 +1011,8 @@ static void stage2_destroy_range(struct kvm_pgtable *pgt, phys_addr_t addr, do { next = stage2_range_addr_end(addr, end); - KVM_PGT_FN(kvm_pgtable_stage2_destroy_range)(pgt, addr, - next - addr); + next = KVM_PGT_FN(kvm_pgtable_stage2_destroy_range)(pgt, addr, next - addr); + next = min(next, end); if (next != end) cond_resched(); } while (addr = next, addr != end); diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 016997288fd23..f21c3326dda68 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -499,14 +499,14 @@ static int __pkvm_pgtable_stage2_unshare(struct kvm_pgtable *pgt, u64 start, u64 return 0; } -void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, - u64 addr, u64 size) +u64 pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, + u64 addr, u64 size) { struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu); pkvm_handle_t handle = kvm->arch.pkvm.handle; if (!handle) - return; + return addr + size; if (pkvm_hyp_vm_is_created(kvm) && !kvm->arch.pkvm.is_dying) { WARN_ON(kvm_call_hyp_nvhe(__pkvm_start_teardown_vm, handle)); @@ -517,6 +517,8 @@ void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, __pkvm_pgtable_stage2_reclaim(pgt, addr, addr + size); else __pkvm_pgtable_stage2_unshare(pgt, addr, addr + size); + + return addr + size; } void pkvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt) -- 2.47.3