From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E2E7840B362 for ; Tue, 30 Jun 2026 12:11:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782821487; cv=none; b=ChlxLb2P3t5/F55nUsUNQI7l7fiSCVyev5USO5TrLzK2AU6e01gAnL5XZf0H3yjz5rcGkzH/XyD7i1EbLABOOP2hv7FmafNeHXqjpdczi7wjXzrGC1y5+tB1fUvJqvTAkbFs2oOKDW4jjqgsm8VDUqQ3QbX3t1dqNlCLcYucJzM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782821487; c=relaxed/simple; bh=E7+qqt2CDSjvyTnRaP+lWOF/gpnYwiJEJNdcRjtcUKw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HDAR1ty+7th70M4YTAM7fge78WVIschwQ/vvxPUgh0ge9xXs60t6Cn0V20rrzhH3s9j+2OEXbMDpUp9/CJ5mn4KWukkI99qBJKjC7U11KaEAtQ6QI6y5/x+8PY/jxD5ubliiUbkRf25OZHGEXxUi4EJ789sOAnMSWfx2zzDaIzQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=sro8KjLG; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="sro8KjLG" 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 E0A9B2C46; Tue, 30 Jun 2026 05:11:20 -0700 (PDT) Received: from workstation-e142269.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3540C3F905; Tue, 30 Jun 2026 05:11:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782821485; bh=E7+qqt2CDSjvyTnRaP+lWOF/gpnYwiJEJNdcRjtcUKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sro8KjLGS/R/zAIi0/8WJL4HpRRCQmjqytT6OEL9seTHr+/yagTQF1CMgbK27HOSj MR7aUDlsUo0CzeKSm8oqSxilDrm32zg2/6fLdBGoOr1S/JC0eUQ9TIOIvO2p8L4j04 zapQbxi1x2n/kb7GMpyC9m4BNldE60JCGUlOt10E= From: Wei-Lin Chang To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Marc Zyngier , Oliver Upton , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Itaru Kitayama , Sebastian Ene , Wei-Lin Chang Subject: [PATCH v2 1/6] KVM: arm64: ptdump: Remove shadow ptdump files Date: Tue, 30 Jun 2026 13:10:00 +0100 Message-ID: <20260630121005.1130996-2-weilin.chang@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260630121005.1130996-1-weilin.chang@arm.com> References: <20260630121005.1130996-1-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-Transfer-Encoding: 8bit Previously we exposed shadow page tables by creating a debugfs ptdump file whenever a nested mmu instance gets bound to a new context, and deleting the debugfs file whose context was getting unbound. This turned out to be buggy, as the instance<->context binding process is done with the mmu_lock held, and debugfs creation/deletion can sleep. Revert most of commit 19e15dc73f0f ("KVM: arm64: nv: Expose shadow page tables in debugfs"), keep the "nested" debugfs directory for use in a later patch where we'll expose the shadow ptdump in another way. Fixes: 19e15dc73f0f ("KVM: arm64: nv: Expose shadow page tables in debugfs") Reported-by: Itaru Kitayama Closes: https://lore.kernel.org/kvmarm/aiuF0KSvvv-ZozI1@sm-arm-grace07/ Signed-off-by: Wei-Lin Chang --- arch/arm64/include/asm/kvm_host.h | 5 +---- arch/arm64/include/asm/kvm_mmu.h | 4 ---- arch/arm64/kvm/nested.c | 6 +----- arch/arm64/kvm/ptdump.c | 23 ----------------------- 4 files changed, 2 insertions(+), 36 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 2faa60df847d..94bced53a323 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -217,10 +217,6 @@ struct kvm_s2_mmu { */ bool nested_stage2_enabled; -#ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS - struct dentry *shadow_pt_debugfs_dentry; -#endif - /* * true when this MMU needs to be unmapped before being used for a new * purpose. @@ -424,6 +420,7 @@ struct kvm_arch { /* Nested virtualization info */ struct dentry *debugfs_nv_dentry; #endif + }; struct kvm_vcpu_fault_info { diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 6eae7e7e2a68..c1e535e3d931 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -392,12 +392,8 @@ static inline bool kvm_supports_cacheable_pfnmap(void) #ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS void kvm_s2_ptdump_create_debugfs(struct kvm *kvm); -void kvm_nested_s2_ptdump_create_debugfs(struct kvm_s2_mmu *mmu); -void kvm_nested_s2_ptdump_remove_debugfs(struct kvm_s2_mmu *mmu); #else static inline void kvm_s2_ptdump_create_debugfs(struct kvm *kvm) {} -static inline void kvm_nested_s2_ptdump_create_debugfs(struct kvm_s2_mmu *mmu) {} -static inline void kvm_nested_s2_ptdump_remove_debugfs(struct kvm_s2_mmu *mmu) {} #endif /* CONFIG_PTDUMP_STAGE2_DEBUGFS */ #endif /* __ASSEMBLER__ */ diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index faa4a48f265d..6435efd65cb5 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -834,10 +834,8 @@ static struct kvm_s2_mmu *get_s2_mmu_nested(struct kvm_vcpu *vcpu) kvm->arch.nested_mmus_next = (i + 1) % kvm->arch.nested_mmus_size; /* Make sure we don't forget to do the laundry */ - if (kvm_s2_mmu_valid(s2_mmu)) { - kvm_nested_s2_ptdump_remove_debugfs(s2_mmu); + if (kvm_s2_mmu_valid(s2_mmu)) s2_mmu->pending_unmap = true; - } /* * The virtual VMID (modulo CnP) will be used as a key when matching @@ -851,8 +849,6 @@ static struct kvm_s2_mmu *get_s2_mmu_nested(struct kvm_vcpu *vcpu) s2_mmu->tlb_vtcr = vcpu_read_sys_reg(vcpu, VTCR_EL2); s2_mmu->nested_stage2_enabled = vcpu_read_sys_reg(vcpu, HCR_EL2) & HCR_VM; - kvm_nested_s2_ptdump_create_debugfs(s2_mmu); - out: atomic_inc(&s2_mmu->refcnt); diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c index c9140e22abcf..7c32f1f7772c 100644 --- a/arch/arm64/kvm/ptdump.c +++ b/arch/arm64/kvm/ptdump.c @@ -17,7 +17,6 @@ #define MARKERS_LEN 2 #define KVM_PGTABLE_MAX_LEVELS (KVM_PGTABLE_LAST_LEVEL + 1) -#define S2FNAMESZ sizeof("0x0123456789abcdef-0x0123456789abcdef-s2-disabled") struct kvm_ptdump_guest_state { struct kvm_s2_mmu *mmu; @@ -273,28 +272,6 @@ static const struct file_operations kvm_pgtable_levels_fops = { .release = kvm_pgtable_debugfs_close, }; -void kvm_nested_s2_ptdump_create_debugfs(struct kvm_s2_mmu *mmu) -{ - struct dentry *dent; - char file_name[S2FNAMESZ]; - - snprintf(file_name, sizeof(file_name), "0x%016llx-0x%016llx-s2-%sabled", - mmu->tlb_vttbr, - mmu->tlb_vtcr, - mmu->nested_stage2_enabled ? "en" : "dis"); - - dent = debugfs_create_file(file_name, 0400, - mmu->arch->debugfs_nv_dentry, mmu, - &kvm_ptdump_guest_fops); - - mmu->shadow_pt_debugfs_dentry = dent; -} - -void kvm_nested_s2_ptdump_remove_debugfs(struct kvm_s2_mmu *mmu) -{ - debugfs_remove(mmu->shadow_pt_debugfs_dentry); -} - void kvm_s2_ptdump_create_debugfs(struct kvm *kvm) { debugfs_create_file("stage2_page_tables", 0400, kvm->debugfs_dentry, -- 2.43.0