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 F00D8C43458 for ; Wed, 1 Jul 2026 15:28:49 +0000 (UTC) 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: Content-Type: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=KYCSlMCtnKle9KfYPLoN/31sjLfbzjORTY7QSZ4HZt8=; b=fSuLMyWHmL8UGXZVV9g3OFkhBZ AUqLgsiOzN76B1vAdpsqoloKEm15YCJMD3oD4upBWEAH7BbtZy8ZmKVtoQ5T6MCwtKAepjSF79jng YQxQM+sDCk47qeBy6LK95C9s5pXJefXs5KPZ++/keYifFY+AXQESiAPXdYTLQqYyL4Id8QeQvgFGd /g3d+38Zof03lo9fkKNek2NZTs8U8XXFzfxwgGG4HP+WcT9IsUESZj6dJmp27p2n3D02Z4N0E6bf0 WXJOCty13B1AAmXOEynzEQ+/O590hPIem9GmCYccu99EYlMhAP0d3iULgCprzrFFsdFfjiyIALaHK xSQlXHIw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wewri-00000002OfP-2HuE; Wed, 01 Jul 2026 15:28:42 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wewrg-00000002Oev-48eG for linux-arm-kernel@lists.infradead.org; Wed, 01 Jul 2026 15:28:42 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5D7791595; Wed, 1 Jul 2026 08:28:35 -0700 (PDT) Received: from LeoBrasDK.cambridge.arm.com (LeoBrasDK.cambridge.arm.com [10.2.212.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 781E23F85F; Wed, 1 Jul 2026 08:28:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782919719; bh=34DjKykF6QNsTTgFP+fjINVEdklK8DtnU8FdOfZVAUo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t1MQ/6HFPHnjzUR8vossSiIhHH+mQqrQZULu2NM3rrgEE8mIWN8W24svLKd3SFvfS 604I5nbLMaGNoW1EQ0Z3F2f4iZOA/esIcfmmEj1JwtvezgYdJPkgv6x7ghEEFR/SFK oPQzrEAfMmrTU8JY2mY5BPxCI53Knk7bwHlUQ9XE= From: Leonardo Bras To: Wei-Lin Chang Cc: Leonardo Bras , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Marc Zyngier , Oliver Upton , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Itaru Kitayama , Sebastian Ene Subject: Re: [PATCH v2 6/6] KVM: arm64: ptdump: Introduce the shadow ptdump file Date: Wed, 1 Jul 2026 16:28:35 +0100 Message-ID: X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260630121005.1130996-7-weilin.chang@arm.com> References: <20260630121005.1130996-1-weilin.chang@arm.com> <20260630121005.1130996-7-weilin.chang@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260701_082841_116593_9A81D0D2 X-CRM114-Status: GOOD ( 25.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 30, 2026 at 01:10:05PM +0100, Wei-Lin Chang wrote: > Create a ptdump file for all shadow page tables. It will dump out all > valid shadow page tables at the time of request, with the mmu's index, > guest VTCR_EL2, VTTBR_EL2, and whether the guest stage-2 is enabled or > not. > > Also detach the nested mmu array under the mmu_lock in > kvm_arch_flush_shadow_all() so readers cannot race with the array being > removed, then free the old array after dropping the lock. Out of curiosity: why drop the lock before kfree'ing ? Thanks! Leo > > Signed-off-by: Wei-Lin Chang > --- > arch/arm64/kvm/nested.c | 12 ++++++-- > arch/arm64/kvm/ptdump.c | 61 ++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 69 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c > index 6435efd65cb5..17a180ddf6ca 100644 > --- a/arch/arm64/kvm/nested.c > +++ b/arch/arm64/kvm/nested.c > @@ -1283,6 +1283,7 @@ void kvm_nested_s2_flush(struct kvm *kvm) > > void kvm_arch_flush_shadow_all(struct kvm *kvm) > { > + struct kvm_s2_mmu *mmus; > int i; > > for (i = 0; i < kvm->arch.nested_mmus_size; i++) { > @@ -1291,9 +1292,14 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm) > if (!WARN_ON(atomic_read(&mmu->refcnt))) > kvm_free_stage2_pgd(mmu); > } > - kvfree(kvm->arch.nested_mmus); > - kvm->arch.nested_mmus = NULL; > - kvm->arch.nested_mmus_size = 0; > + > + scoped_guard(write_lock, &kvm->mmu_lock) { > + mmus = kvm->arch.nested_mmus; > + kvm->arch.nested_mmus = NULL; > + kvm->arch.nested_mmus_size = 0; > + } > + > + kvfree(mmus); > kvm_uninit_stage2_mmu(kvm); > } > > diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c > index 40f93b7c7ad9..1649eaa75798 100644 > --- a/arch/arm64/kvm/ptdump.c > +++ b/arch/arm64/kvm/ptdump.c > @@ -181,6 +181,50 @@ static int kvm_ptdump_guest_canonical_show(struct seq_file *m, void *unused) > return 0; > } > > +static int kvm_ptdump_guest_nested_show(struct seq_file *m, void *unused) > +{ > + int ret = 0, i; > + struct kvm_ptdump_guest_state *st = m->private; > + struct kvm *kvm = st->kvm; > + struct kvm_pgtable_walker walker = (struct kvm_pgtable_walker) { > + .cb = kvm_ptdump_visitor, > + .arg = &st->parser_state, > + .flags = KVM_PGTABLE_WALK_LEAF, > + }; > + > + guard(write_lock)(&kvm->mmu_lock); > + > + if (!kvm->arch.nested_mmus) > + return 0; > + > + for (i = 0; i < kvm->arch.nested_mmus_size; i++) { > + struct kvm_s2_mmu *mmu = &kvm->arch.nested_mmus[i]; > + > + if (!mmu->pgt) > + continue; > + > + if (kvm_s2_mmu_valid(mmu)) { > + memset(st, 0, sizeof(*st)); > + ret = kvm_ptdump_parser_init(st, kvm, mmu->pgt); > + if (ret) > + return ret; > + st->parser_state = (struct ptdump_pg_state) { > + .marker = &st->ipa_marker[0], > + .level = -1, > + .pg_level = &st->level[0], > + .seq = m, > + }; > + seq_printf(m, "nested mmu %d VTCR: 0x%016llx VTTBR: 0x%016llx s2: %s\n", > + i, mmu->tlb_vtcr, mmu->tlb_vttbr, > + mmu->nested_stage2_enabled ? "enabled" : "disabled"); > + ret = kvm_pgtable_walk(mmu->pgt, 0, BIT(mmu->pgt->ia_bits), &walker); > + if (ret) > + return ret; > + } > + } > + return ret; > +} > + > static int kvm_ptdump_guest_open(struct inode *m, struct file *file, > int (*show)(struct seq_file *, void *)) > { > @@ -212,6 +256,11 @@ static int kvm_ptdump_guest_canonical_open(struct inode *m, struct file *file) > return kvm_ptdump_guest_open(m, file, kvm_ptdump_guest_canonical_show); > } > > +static int kvm_ptdump_guest_nested_open(struct inode *m, struct file *file) > +{ > + return kvm_ptdump_guest_open(m, file, kvm_ptdump_guest_nested_show); > +} > + > static int kvm_ptdump_guest_close(struct inode *m, struct file *file) > { > struct kvm *kvm = m->i_private; > @@ -230,6 +279,13 @@ static const struct file_operations kvm_ptdump_guest_canonical_fops = { > .release = kvm_ptdump_guest_close, > }; > > +static const struct file_operations kvm_ptdump_guest_nested_fops = { > + .open = kvm_ptdump_guest_nested_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = kvm_ptdump_guest_close, > +}; > + > static int kvm_pgtable_range_show(struct seq_file *m, void *unused) > { > struct kvm *kvm = m->private; > @@ -307,6 +363,9 @@ void kvm_s2_ptdump_create_debugfs(struct kvm *kvm) > kvm, &kvm_pgtable_range_fops); > debugfs_create_file("stage2_levels", 0400, kvm->debugfs_dentry, > kvm, &kvm_pgtable_levels_fops); > - if (cpus_have_final_cap(ARM64_HAS_NESTED_VIRT)) > + if (cpus_have_final_cap(ARM64_HAS_NESTED_VIRT)) { > kvm->arch.debugfs_nv_dentry = debugfs_create_dir("nested", kvm->debugfs_dentry); > + debugfs_create_file("shadow_page_tables", 0400, kvm->arch.debugfs_nv_dentry, > + kvm, &kvm_ptdump_guest_nested_fops); > + } > } > -- > 2.43.0 >