From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from esa1.hc1455-7.c3s2.iphmx.com (esa1.hc1455-7.c3s2.iphmx.com [207.54.90.47]) (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 8D1DF31B130 for ; Wed, 16 Sep 2026 04:58:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.54.90.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789534702; cv=none; b=Pu3VzKoSpGokCBebCgjVlePdkLJzBNQjWpNhKX2FNS5kEAGRKrLsn7dDIEWtj9+2ACLtDSWwFeha8j1zbvbw+6CRua/8VC9228nh6KV92lxHQlJVNN50eT0e2Fk8VSzzaGf3Lv0GjUUjzwxcpmm4SiXvzelTkcv6hDoIi3xDmLg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789534702; c=relaxed/simple; bh=SnAcro5Dui87SihtGm652xAlG5XwDxA05uuCThf6Qp4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UXLCdIslcbwmfqBIYO/GcO5Hi6bDHs9+T5xK1JTevTMSL/CvkhidfJwHY1YeBS4xueCs9oSnRNruxBg5qAzisMIpsvNpRBGQKVxDSC6UJOvWvcYLuzTkAkzj9roAfnOEmUEpvvpSKYbeusdW9UtDK8f+utAKPVBxdOWqp7YRM6c= 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=uIIWP4gF; arc=none smtp.client-ip=207.54.90.47 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="uIIWP4gF" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=fujitsu.com; i=@fujitsu.com; q=dns/txt; s=fj2; t=1789534705; x=1821070705; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=SnAcro5Dui87SihtGm652xAlG5XwDxA05uuCThf6Qp4=; b=uIIWP4gFFId3491bzGj67WGag7pRJig9n6Pe1CTviKS+lu7ooiFkW0kI zieg+JC6f+V7gVw3UL0/9FVhujKAy0Ok7fegohwvL+AWY7+/akxhXfK+k Ez21ljLjsYvQI/LN8nln1rEYERLBgYcJl2ggNqtB/KbVAJRMy0uxuLND7 w+eyVmdKlAq+JQUp7QvqCBZcxN8xChQQf/XiWxPPjhUzBhZSa4zm5rpRj 6miYZ5yfCoQJpayk2AydM6SBfN634jbOPJwC+xmRkwtZZ9RyU5L0mJ3Q0 tyJpbC00ai9XaVvc7Hi7QaEmc5WzH96X4MHXGzPZmkC6i8hWI6HEeCDbe Q==; X-CSE-ConnectionGUID: GJXO5kmcQreFjaRR2q6NyA== X-CSE-MsgGUID: qMKfUJCRQU+FhHn5hgmctA== X-IronPort-AV: E=McAfee;i="6800,10657,11905"; a="255212538" X-IronPort-AV: E=Sophos;i="6.27,103,1786978800"; d="scan'208";a="255212538" Received: from gmgwnl01.global.fujitsu.com ([52.143.17.124]) by esa1.hc1455-7.c3s2.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Sep 2026 13:58:17 +0900 Received: from az2nlsmgm2.o.css.fujitsu.com (unknown [10.150.26.202]) (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 gmgwnl01.global.fujitsu.com (Postfix) with ESMTPS id B4EDB407547 for ; Wed, 16 Sep 2026 04:58:12 +0000 (UTC) Received: from az2nlsmom3.fujitsu.com (unknown [10.150.26.199]) (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 az2nlsmgm2.o.css.fujitsu.com (Postfix) with ESMTPS id 653741C00152 for ; Wed, 16 Sep 2026 04:58:12 +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 az2nlsmom3.fujitsu.com (Postfix) with ESMTPS id 497CD100019E; Wed, 16 Sep 2026 04:58:06 +0000 (UTC) Date: Wed, 16 Sep 2026 13:58:03 +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 , Mark Rutland , Wang Han , Shuai Xue , "Lorenzo Stoakes (ARM)" Subject: Re: [PATCH v6 0/7] KVM: arm64: nv: Implement nested stage-2 reverse map Message-ID: References: <20260915154305.3852871-1-weilin.chang@arm.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260915154305.3852871-1-weilin.chang@arm.com> Hi Wei-Lin, On Tue, Sep 15, 2026 at 04:42:58PM +0100, Wei-Lin Chang wrote: > Hi, > > This is v6 of optimizing the shadow s2 mmu unmapping during MMU > notifiers. > > This version fixes a few issues, and adds Marc's space optimization > for kvm_guest_s2_mapping [1]. Please see the changelog for the details. > > Tested by booting L3, and running in-kernel targetted tests described > in [2]. v5 got some tested-by's from Itaru and Wang (thanks), I didn't > carry them over since some bugs fixed in v6 are non-obvious. Some > retest would be much appreciated! > > Series based on v7.3-rc3 + Marc's nested mmu lifecycle fixes [3]. Observed on QEMU (accel tcg) only, but I saw: [ 1812.052752] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1630 [ 1812.052896] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 596, name: shadow_stage2 The kernel is built on top of Marc's fix and your version six series, but the fix for debugfs will be posted later? Your hello_nested and shadow_stage2 ran without an issue. Tested-by: Itaru Kitayama Thanks, Itaru. > > * Changes from v5 [4]: > > - Align the addresses down to the mapping size when recording the > guest s2 mappings. s2fd->fault_ipa isn't necessarily PAGE_SIZE aligned. > > - Record guest s2 mappings even when page table maps return -EAGAIN. > kvm_pgtable_stage2_map() can create mappings while returning -EAGAIN. > For example, a 2M block map (A) could race with a 4K page map (B): > 1. (A) maps the 2M block in kvm_pgtable_visitor_cb() > 2. (B) breaks that block into a table and maps 4K > 3. (A) reloads and finds the table after kvm_pgtable_visitor_cb(), > then descends into it. > 4. (A) maps some 4K, but before it finishes reads entry mapped by (B). > 5. (A) returns -EAGAIN although it had mapped a few pages. > In this case, we don't know what subrange is mapped, just track the whole > requested mapping range. > > - Don't remove tracked mappings from the interval trees if they only > partially overlap the removal range. Because of the previous bullet point > we can have a 4K shadow mapping tracked as a 2M range in the interval > trees. It would be wrong to remove the 2M range when a guest TLBI doesn't > touch the 4K mapped. > > - Check mmu->pgt during mmu unmap notifier, as it could race against > MMU teardown. > > - Make guest_s2_tracking_destroy() canonical mmu only. We simply don't > need to detach the nodes from the nested mmus' trees. Freeing them > during canonical mmu's teardown is enough. > > Thanks! > > [1]: https://lore.kernel.org/kvmarm/86h5jv7qrd.wl-maz@kernel.org/ > [2]: https://lore.kernel.org/kvmarm/gerjpm62a2gszzggc6vuai22bf3prfquvfsp7ueumps7vz2ev3@odlmovaklg2b/ > [3]: https://lore.kernel.org/kvmarm/20260911162203.1919330-1-maz@kernel.org/ > [4]: https://lore.kernel.org/kvmarm/20260810205038.118843-1-weilin.chang@arm.com/ > > Marc Zyngier (1): > KVM: arm64: nv: Drop kvm_s2_mmu pointer from kvm_guest_s2_mapping > > Wei-Lin Chang (6): > KVM: arm64: Use a variable for the canonical IPA in kvm_s2_fault_map() > KVM: arm64: nv: Introduce guest stage-2 tracking structures > KVM: arm64: nv: Track guest stage-2 mapping creation > KVM: arm64: nv: Track guest stage-2 mapping removal > KVM: arm64: nv: Avoid full shadow stage-2 unmap > KVM: arm64: Refactor kvm_unmap_gfn_range() with common variables > > arch/arm64/include/asm/kvm_host.h | 31 +++++- > arch/arm64/include/asm/kvm_nested.h | 7 ++ > arch/arm64/kvm/mmu.c | 109 +++++++++++++++++++--- > arch/arm64/kvm/nested.c | 140 +++++++++++++++++++++++++++- > 4 files changed, 269 insertions(+), 18 deletions(-) > > -- > 2.43.0 >