From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.221.41 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793871928; b=qYDqafUTLwLukGI30WEvH2RsoXNKvG5Zb6GGcFh0JuGYhiEbdWRYAz0Yn4g30BJeLQAJ fjNg18uH/uU8ZnylFbkomRqI7oO2Yy0ktwCzSuMisSL5FLnAnFAwu7zCEQ284Sphwlb0K gXBCGcwvt79AmZoJ26jNSUFzPh//sazxYshAm6APXS7R0wOsGPw3mEajV09rW3/ZnpViG dH8D85+iLWtMTTW3tFVcfvBmwaO2mmoDYyXJaeEXuiTu7vFy3dDJd6dF0CIEX8+90h3hd m727V6vUTT18u1zM+IdkSLRSXUmxxOW6dPNH+ZKQCXj6BKSevJNMFC+hFu7YJjGTpzw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793871928; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; bh=hI6E0pWdIjYridUcVEtGitpYPVkZ0Czh5YzRDUq6aT8=; b=z7UkdeVPMDnrEGKB3/Knl8uqNO8mnvcje2ZeSmJMfXWNZhKmTvbj+CNAHEd4dpWxi/l7 oxqHZ/TP+879URm1VZK2hoUWO0HjPAnganhOBaSAf5P2/vWFcVaHDmt+7cGouHVWaJux0 md70LmXy3iMzhbpfbB7nPkP+OOh6cUVix+Scjww6EeIRSNR2K/IHQFrSEQ6tqM64W15KL 1fXVRqXh3cMxrZdu0Mxj62ILXYzJ6sMUnpFAiYHT+uyYTeVJmcoQ4In51qUAnql3O6vtK X21gn9VC9DLHtgQKkU9WrGWfBiwyETnAh0y+MCJJXT2qvC7qwa3cNPwapiRS+DEhRew== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=LHOXFIlr; arc=none smtp.remote-ip=209.85.221.41 Received: from mail-wr1-f41.google.com (mail-wr1-f41.google.com [209.85.221.41]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 02EEF606A326 for ; Thu, 5 Nov 2026 09:45:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 02EEF606A326 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20260707 header.b=LHOXFIlr Received: by mail-wr1-f41.google.com with SMTP id ffacd0b85a97d-48fd2e38825so1111108f8f.2 for ; Thu, 05 Nov 2026 01:45:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20260707; t=1793871925; x=1794476725; darn=lists.linux.dev; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=hI6E0pWdIjYridUcVEtGitpYPVkZ0Czh5YzRDUq6aT8=; b=LHOXFIlrh30/DqJx/PKINA30gRtrbMjTxhMxjY7GD6vwaruau/jsZWiccQbRUCw27Z jowwuO2fsXgLttUKlRwsTmmifXmqbG1EpOQhJR4zuvLy6nOkkeyT2fynw4aUB5zhM379 0MpbyaPqaNGAQI5N5Q6PpnHO+uZyTsm++ee5oc30Twthqs/MlhvJeAY5b78QS1nNoLvj 58gpamd3GvLcfSWOuVWfPNgi6QhRkC3al3ZIGPYIFzCQK+T6ggiAFqEQkVEJZi8EaoET lMK17jTnDZFs5jUhIavsWtTAXxWUZROgX9NplSFkIdQyHRZfB8Wd+FqUd6mQSYD2hLch Qp0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793871925; x=1794476725; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=hI6E0pWdIjYridUcVEtGitpYPVkZ0Czh5YzRDUq6aT8=; b=kAqm/8Npg3jyQqO7XI7Fl01hvCMAW/BliBElxwho3JoAYgwoC0+UwfusX4vlwRfNZW +M+UbE4yaXnMpGaaH7qs87yexb5OI5K8f5Y5jg47dYs4Onj5tpQUHnaYDWN50mt8y6fr iZfLikOD87lA8pgZXIuB3FcLd/LNPPZut9UjtOWWNQn+SZU4UxbRXZkSkP6ZsRIU0+5I mfOIggUVokHqiUNf8mBVkVfJXlS4PaZdE9rPVhworRejWKRC2Nz+Kv59iMXHJTpdhK6t aaxkytqohoyz8pq1TM/J4IJjyfruQK8VqsCC9er2/belbpATS1/f8SSquKDbEVdXsqby Kpow== X-Forwarded-Encrypted: i=1; AKwUvBw322p5XnB5kGgZiwkiMLsN4XBBQ0+a72QtPURZ8oob+1qn5u687QPxlxTondgoVvBUyxkZIAM=@lists.linux.dev X-Gm-Message-State: APuU4Z9rd2lGThL7wUwUm7P74d5WBVEOo5y7MX0dlnmaqr796SAOW3k+ aXUhMflzscNXYvOdSEXS9W0KktoU8AosV1ih0Y2FfFlcrBcDxigH8P59eCNh2l1ydw== X-Gm-Gg: AYBFou2i6+mBiaRTNCkHFrDuZPCZuUtG4aJgzmok2HVr3AxTIQ2fON2zJU+yPneE3Bu 2UzLiLdEi8N+KI++BLH8KAGo68daOeHueK/x2z0geerDtFemjh4LzqE1gvrb+wzQXH77RuWma6F 7w7YUpRnXltRVZKiCuhZSgiEBruO9LGPBrAvd07+PpbQnwU9YgToFpri3BW/4dk68497At1t+6U K6bcjsxe5Fw73qr96I35fFuctPvepQM9i3OR3oE9t2GDompbKx0WWa+dpX2FUz3yhDJVo6TOEWk oADB30Dm3zz4ZgHGg4rzxRvApjZDgrFLyA+lRSrZt78iSoon18XpnT96hSfJhi/fZiwpKidfhAQ ZWta5mD+hZh7zx/NaWI+VQokObbnHEpSpMAJK2ft1vnt90SB9Ks0CLPsdGUbkdbuT+OGcbaDpd1 U5s4h/saD+YxcCR/F6A8gc16s4Wj+37KM0UUD181f5JOVofsFhQRhwPyOpIQW16Zll7J4nQK9p9 DcITLuT/QFpu03WXBOPbfP3M9rcmYtPRiwfyeN9GuKyaUXIQruBKHQ8sftJMx0Q2SXGr2gyNUnL bLbPiZbvX7b57+Y2IaH7iAUfDwmNbC2xFVTLcQGJw2u4om4uSbOVPoIK/DMIx15l X-Received: by 2002:a05:6000:1842:b0:48e:3cec:b852 with SMTP id ffacd0b85a97d-48e6e500962mr42464044f8f.40.1793871924816; Thu, 05 Nov 2026 01:45:24 -0800 (PST) Received: from google.com (0.182.34.34.bc.googleusercontent.com. [34.34.182.0]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48fece998absm9721233f8f.22.2026.11.05.01.45.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2026 01:45:24 -0800 (PST) Date: Thu, 5 Nov 2026 09:45:20 +0000 From: Vincent Donnefort To: Fuad Tabba Cc: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Raghavendra Rao Ananta , Fuad Tabba Subject: Re: [PATCH v2 2/2] KVM: arm64: Resume a pKVM stage-2 teardown at the next mapping Message-ID: References: <20261104124451.2148724-1-fuad.tabba@linux.dev> <20261104124451.2148724-3-fuad.tabba@linux.dev> X-Mailing-List: kvmarm@lists.linux.dev 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: <20261104124451.2148724-3-fuad.tabba@linux.dev> On Wed, Nov 04, 2026 at 12:44:51PM +0000, Fuad Tabba wrote: > pKVM keeps a VM's stage-2 mappings in an interval tree, and > pkvm_pgtable_stage2_destroy_range() releases the ones in its range. > stage2_destroy_range() still calls it for every block-sized chunk of the > IPA space. As pKVM gives every VM the host's IPA limit, a teardown with > LPA2 makes 2^27 calls with 16K pages (2^22 with 4K), however little the > VM maps. > > Return the address of the next mapping instead, or U64_MAX when none is > left, so that the teardown skips the space between mappings. No mapping > crosses a chunk boundary, as pKVM maps at most PMD_SIZE, so the next one > starts at or above the end of the range. A VM without a handle doesn't > have anything mapped, so return U64_MAX for it straight away. > > Signed-off-by: Fuad Tabba > --- > arch/arm64/kvm/pkvm.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c > index f21c3326dda68..77315c83c61b3 100644 > --- a/arch/arm64/kvm/pkvm.c > +++ b/arch/arm64/kvm/pkvm.c > @@ -504,9 +504,10 @@ u64 pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, > { > struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu); > pkvm_handle_t handle = kvm->arch.pkvm.handle; > + struct pkvm_mapping *mapping; > > if (!handle) > - return addr + size; > + return U64_MAX; > > if (pkvm_hyp_vm_is_created(kvm) && !kvm->arch.pkvm.is_dying) { > WARN_ON(kvm_call_hyp_nvhe(__pkvm_start_teardown_vm, handle)); > @@ -518,7 +519,10 @@ u64 pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, > else > __pkvm_pgtable_stage2_unshare(pgt, addr, addr + size); > > - return addr + size; > + /* Mappings left by a failed release are still in the tree, so look past the range. */ Hum, not sure I understand that comment. Which release are we talking about? The _reclaim or _unshare? If yes, we don't propagate the error and WARN if any of them fails. So we don't expect any failure here and I'd say there's nothing special to do? Additionally, in any case, iter_first(addr + size) seems like the right thing to do and is self-explanatory. > + mapping = pkvm_mapping_iter_first(&pgt->pkvm_mappings, addr + size, U64_MAX); > + > + return mapping ? gfn_to_gpa(mapping->gfn) : U64_MAX; > } > > void pkvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt) > -- > 2.47.3 > Reviewed-by: Vincent Donnefort -- Vincent