From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from esa10.hc1455-7.c3s2.iphmx.com (esa10.hc1455-7.c3s2.iphmx.com [139.138.36.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D7DF312834 for ; Thu, 2 Jul 2026 21:48:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=139.138.36.225 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783028899; cv=none; b=cM1xbFQezl0PUJFs744msQ8w+kvx2XIItTuHSlM7vOjE+4LEodPpZ/Y+SaUgLC7A8uzZY1pbKwaax7AwEvAznCeFfF3v60pi5GQtUmpWeIsZ9wzdsREo7LsubkYsypTSk2893AVryv1g1l22fQ0YIuK5uOC/5WnMKvtFpIyQxCU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783028899; c=relaxed/simple; bh=eQ/r81yq7SBHVmjU6sNi5AKmD7P2Gx79kRYPEcoBKn4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QgDlD2zg6/d7/hJ35iW/dIb2S7NYjaKDxqjI19xI4bQbG6stT2tYf0EJWgzLKmaCLGmMOLHwDfNnTchYCjpF/pfBsWmahPKBBnINwvy0hRDsGt8tFC5KC7dBiRrgOY6tS0klrlearj9xiBXdY41iiW0lQG8QAVgysInKznZmKU8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fujitsu.com; spf=pass smtp.mailfrom=fujitsu.com; dkim=pass (2048-bit key) header.d=fujitsu.com header.i=@fujitsu.com header.b=AiTI64/u; arc=none smtp.client-ip=139.138.36.225 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fujitsu.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fujitsu.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fujitsu.com header.i=@fujitsu.com header.b="AiTI64/u" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=fujitsu.com; i=@fujitsu.com; q=dns/txt; s=fj2; t=1783028899; x=1814564899; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=eQ/r81yq7SBHVmjU6sNi5AKmD7P2Gx79kRYPEcoBKn4=; b=AiTI64/uicCC/drYyqDrZuNQCmy2kUYmSRMOr8uNOiPuFGk8M8tsk8b1 HSAgf8iSeF7lQBEYtQ93m/WZyzlJ7uKNQPMmvd2PBNXPgYQw3v90tOJJu zPRvwgs+p49jeI6Lpxzd1RtJF//DOkHBtSWd2fpq7umikeBQ42rucmn9f /pf892yNXM/DuCeLhrvMcM0RB3c/1lO5PhAyJXK1QTN/ggwmRV36xqe9S 2ow/am35ArNq0vyl5mmLskK2byMb5uXk/tXfVGV1pudud6cRFd1v24CBi f08qEPsHblzcePBh5OF0hfYJdNBrpcimb6WEWCKnR3nr+9QLjG4Y4I+GC g==; X-CSE-ConnectionGUID: NzE/mTJ/Rou6JUrMWR/kDg== X-CSE-MsgGUID: sY5ms/zpQm+Fmz45McTZIQ== X-IronPort-AV: E=McAfee;i="6800,10657,11835"; a="232287311" X-IronPort-AV: E=Sophos;i="6.25,144,1779116400"; d="scan'208";a="232287311" Received: from gmgwnl01.global.fujitsu.com (HELO mgmgwnl01.global.fujitsu.com) ([52.143.17.124]) by esa10.hc1455-7.c3s2.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jul 2026 06:48:17 +0900 Received: from az2nlsmgm3.fujitsu.com (unknown [10.150.26.205]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mgmgwnl01.global.fujitsu.com (Postfix) with ESMTPS id BBA66CA53 for ; Thu, 2 Jul 2026 21:48:15 +0000 (UTC) Received: from az2uksmom4.o.css.fujitsu.com (unknown [10.151.22.204]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by az2nlsmgm3.fujitsu.com (Postfix) with ESMTPS id 6E3481801EA0 for ; Thu, 2 Jul 2026 21:48:15 +0000 (UTC) Received: from sm-arm-grace07 (unknown [10.124.178.20]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by az2uksmom4.o.css.fujitsu.com (Postfix) with ESMTPS id 7205640260E; Thu, 2 Jul 2026 21:48:10 +0000 (UTC) Date: Fri, 3 Jul 2026 06:48:07 +0900 From: Itaru Kitayama To: Wei-Lin Chang Cc: 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 , Sebastian Ene Subject: Re: [PATCH v2 6/6] KVM: arm64: ptdump: Introduce the shadow ptdump file Message-ID: References: <20260630121005.1130996-1-weilin.chang@arm.com> <20260630121005.1130996-7-weilin.chang@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260630121005.1130996-7-weilin.chang@arm.com> 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. > > 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"); This header information in the debugfs "shadow_page_tables" file, under the nested directory is showing guest hypervisor's configuration while the file is designed to show nested guest's shadwo stage 2 translation tables layouts owned by Host EL2 hypervisor. Is this intentional? Thanks, Itaru. > + 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 >