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 6FF0F606A335 for ; Tue, 3 Nov 2026 16:55:37 +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=O8DAqDy9; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SM9garVI 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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=Uy62sZIrZ53EycNsa0F+QfAVrofv8khe85aXX4gapkQ=; b=O8DAqDy9pr4GMFKcxwvGjL4dLd uj70wCFWf9oNkxe6Tf9aFv7IW7kNaVultmhrt8GfviZ8mqcLA/54UnD8PNVH9t+DI4CEMB00qZ5+l T7tGYr+UFjej7aPmXoPpX/QR6J+3SvXlA50hAz0lMVKAg5uB5en9XOUU8RzvSY4i+TMQgLXxgjQea r6DTAYtJp2Uv4qXmojUJ2wtLuARniJDs9LYI6Hhcm8UMtHz74D60lhYVFuoxZiFRZOc0lLteSonbb hr6shtrD8wckbA9Z+CHURrkx6jAL+wDXiv09b3LLL9Fz9pzdD0fvX1a3pFjFdjKcteXKBKGGYF9Qz LAsD33zQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOHnH-00000003EUV-0h57; Tue, 03 Nov 2026 16:55:31 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOHnG-00000003EUE-12Ms for linux-arm-kernel@lists.infradead.org; Tue, 03 Nov 2026 16:55:30 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id D22DB43BB5; Tue, 3 Nov 2026 16:55:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A09A1F000C1; Tue, 3 Nov 2026 16:55:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793724929; bh=Uy62sZIrZ53EycNsa0F+QfAVrofv8khe85aXX4gapkQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SM9garVI8Du06Zk5PGVus1j5YVh2s2lwl1obZ9eq1O+qxLFFBxvPUJLfTVauKfTU1 Ny2uh64m1SVz5j5rudVJfoL9oD8ZZoE1GlSX9+s0NFuPm5mEzNQgn83hcR2IPRvz+h sXpQ6LuRfkuxBJRkcbksscajhHaoE3TwwX62zBJkoAIicoXwLUGBH95pp7hyYDaIa+ tjpJYoLtaMV1DUZ6BmsJrIVIG0M5b0V/A31CWm1eI6UmF+nkckH8tnGVJ7CLIkjs64 sdqnYEsPzigid3i/OCibJSW7+WGHgtntzLWlEll9d6SmJN71Fb54k3VpWqiyqEnhUg O8CAbTv+8YKNw== Date: Tue, 3 Nov 2026 08:55:28 -0800 From: Oliver Upton To: Fuad Tabba Cc: Suzuki K Poulose , Marc Zyngier , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Steffen Eiden , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Raghavendra Rao Ananta Subject: Re: [PATCH 2/3] KVM: arm64: Skip empty IPA ranges when destroying stage-2 page-tables Message-ID: References: <20261103084742.1302597-1-fuad.tabba@linux.dev> <20261103084742.1302597-3-fuad.tabba@linux.dev> <9841ba98-7f07-4d5d-8397-a07e22ba7f51@arm.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 On Tue, Nov 03, 2026 at 04:19:38PM +0000, Fuad Tabba wrote: > > > @@ -1010,9 +1010,20 @@ static void stage2_destroy_range(struct kvm_pgtable *pgt, phys_addr_t addr, > [...] > > > next = stage2_range_addr_end(addr, end); > > > - KVM_PGT_FN(kvm_pgtable_stage2_destroy_range)(pgt, addr, > > > - next - addr); > > > + kvm_pgtable_stage2_destroy_range(pgt, addr, next - addr); > > > > minor nit: Given the kvm_pgtable_stage2_destroy_range() is the only > > called from here, and this caller would benefit from the walk > > information, would it make sense to return a hint back ? Not sure how > > much of that is possible. We do this in the RMM, always return a hint > > of the next possible address. Of course this is not that expensive > > as the CCA case and could be dealt in a separate series. > > kvm_pgtable_stage2_destroy_range() is also called by > kvm_pgtable_stage2_destroy(), which EL2 uses to free a pKVM guest's > stage-2, so I'd rather not change it in a fix. This one is still an optimization, not a fix. The re-walk after destroy is a bit fiddly, especially when the inner walk knows exactly what IPA it stopped at. Thanks, Oliver