From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793724930; b=ox5xoHDUaklsoJ9Hii8xto02ljje40s+snxGXtf3WnxBDndZvlAoC/tU4qD7DwXmgjgT BFOXIuL3mRGy9W0FbzOmRZn1RbPqDzrxZHmTgvlYJUTYq58oM35w/C17kq1JdshnIT5pI FrnP+nTvc7J+Guw7N/eEd03EZMOc2gnJdf9pzTCb8LT5yvMP8VfqszXY0agX49YWLygsh /4TkIlsHJV7SFWqRpL0yb1LCzf7O1jhQEJdR4+A752DAFYZby0RDFAbRTXcOI33UW+7SO /oCSn1pRCrMXyDz6q1cEzRq2OjaJyYUzWM2honPEvlWTBdPJ040yg+5mW/sZ1sgO8YQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793724930; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=Uy62sZIrZ53EycNsa0F+QfAVrofv8khe85aXX4gapkQ=; b=5T/mH6paOrxXAB0utKOSzUGxPGQkCd0pK1MlDkF03wtPRiJa7Hdpsf+AV4RJe5pLkFsa nrSWhCW264f/5b6C1J7uc+I2xpgyPa7Tn7qgcUzNk5vaDS3NKM2urxLqn1swFFFHh7efz 49hZ9bdPyLJ1FxLGwPIh0o7J7+VQegH35eEC/iSnA9Tuw5bk2eQlNoIAPLFyo3j0kkAEG PMrig3FUF3gLEEflAcxuSCTdUSQJ9gUf9PZa4eP2W0/9GyMWqIk8WkcipApkpdlbxQ6+r 6N4hW1nilKb9K8vzElJMwCHoo9SkgiGWDAJrr75wHUv8kvFPwZchr8yc7/DiZFDJt6Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SM9garVI; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9673606A324; Tue, 3 Nov 2026 16:55:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SM9garVI 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-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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