From nobody Wed Sep 17 08:10:19 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9F8EC10F1D for ; Fri, 23 Dec 2022 00:58:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229976AbiLWA6D (ORCPT ); Thu, 22 Dec 2022 19:58:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229506AbiLWA5v (ORCPT ); Thu, 22 Dec 2022 19:57:51 -0500 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C80E82180A for ; Thu, 22 Dec 2022 16:57:50 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id b17-20020a170903229100b00189da3b178bso2380070plh.7 for ; Thu, 22 Dec 2022 16:57:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=j9glXQlCcjBPy6z6EtMDUxvhVYrjcVK6NuBTr5d5jMM=; b=mkY/HDRSL1Z6rYMsp5aXb9DxEbw3gk63aqofEQZb3aH6jx7uKj9w6DLcqGi4YUt4GK USLw0pllD+LT2V0T4rKGxQ4b/Lblx2DVggISei1TzjSVCnc8zMjn1lio4lsBy9BbecDd 1OQVdcI3QScS20VMK/rqf/8ZZwsNlbifWB5BVSA/j7sCaOREjYXVLJMn61rP+5G+CLVb XgXuOIs4pXoXR8H4Mu8tIH7tMRiw3NgBhXAaeIbbagBzgXz4ricByiRWhna+M7g7iLFh 37Mo0NbuZa1D2jhxiZvNFCoF/tNc67hLo5Iiu6h+YklyXPtB7Jlz3JOEXdZfa3yDJTWx 11GQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=j9glXQlCcjBPy6z6EtMDUxvhVYrjcVK6NuBTr5d5jMM=; b=5NsH09/zOfMyHl0x5hixkh8oK7hRmircgV/68N9lOJkw1bLdY0x/HGpy3FNch1gmrU pCkE8xOmmOSz21q3irJCBwybBJIDPKq/nS6nB9bLZHjclvjHolwDDbDFDQ2tIKNPLLfp VD+Wv0NLMzFwmGCLsxIjL+QRgJ+9UT3D86xEjMaelFmb1mWW3Kd1oGoUwmtFSh+jf5pw lNEBQcsFK3TPS5XzcSap5AHWITjmHLluCFgFAhfbHl0af5ppyy+d7Wn6rGk0HcvtFqSe Cdq0Fg9xlGzLv3wZpgTX5uKKXmrltbceyT0yCg460FK1x5oB80YHNJ+QCIJm6YxTLrCu TURw== X-Gm-Message-State: AFqh2koqoAYhRhMgyMMdFCG4aHsP3tl54jlSBLtH/CrY54Rg0njVACRn j6jwPTVnVxpa50GMPa5Ekp7jvkKK1ug= X-Google-Smtp-Source: AMrXdXtMbZNNIlGG/KYBUr4YpZKchMqLawm/s6Awbw8/z1k3argf7yO0AX13QDZvc3DFh6qwcnZWOCffa1w= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a62:6242:0:b0:580:9554:d267 with SMTP id w63-20020a626242000000b005809554d267mr23193pfb.20.1671757070371; Thu, 22 Dec 2022 16:57:50 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 23 Dec 2022 00:57:15 +0000 In-Reply-To: <20221223005739.1295925-1-seanjc@google.com> Mime-Version: 1.0 References: <20221223005739.1295925-1-seanjc@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20221223005739.1295925-4-seanjc@google.com> Subject: [PATCH 03/27] drm/i915/gvt: Incorporate KVM memslot info into check for 2MiB GTT entry From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Zhenyu Wang , Zhi Wang Cc: kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, Yan Zhao , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Honor KVM's max allowed page size when determining whether or not a 2MiB GTT shadow page can be created for the guest. Querying KVM's max allowed size is somewhat odd as there's no strict requirement that KVM's memslots and VFIO's mappings are configured with the same gfn=3D>hva mapping, but the check will be accurate if userspace wants to have a functional guest, and at the very least checking KVM's memslots guarantees that the entire 2MiB range has been exposed to the guest. Note, KVM may also restrict the mapping size for reasons that aren't relevant to KVMGT, e.g. for KVM's iTLB multi-hit workaround or if the gfn is write-tracked (KVM's write-tracking only handles writes from vCPUs). However, such scenarios are unlikely to occur with a well-behaved guest, and at worst will result in sub-optimal performance. Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support") Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_page_track.h | 2 ++ arch/x86/kvm/mmu/page_track.c | 18 ++++++++++++++++++ drivers/gpu/drm/i915/gvt/gtt.c | 10 +++++++++- 3 files changed, 29 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/k= vm_page_track.h index eb186bc57f6a..3f72c7a172fc 100644 --- a/arch/x86/include/asm/kvm_page_track.h +++ b/arch/x86/include/asm/kvm_page_track.h @@ -51,6 +51,8 @@ void kvm_page_track_cleanup(struct kvm *kvm); =20 bool kvm_page_track_write_tracking_enabled(struct kvm *kvm); int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot); +enum pg_level kvm_page_track_max_mapping_level(struct kvm *kvm, gfn_t gfn, + enum pg_level max_level); =20 void kvm_page_track_free_memslot(struct kvm_memory_slot *slot); int kvm_page_track_create_memslot(struct kvm *kvm, diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index 2e09d1b6249f..69ea16c31859 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -300,3 +300,21 @@ void kvm_page_track_flush_slot(struct kvm *kvm, struct= kvm_memory_slot *slot) n->track_flush_slot(kvm, slot, n); srcu_read_unlock(&head->track_srcu, idx); } + +enum pg_level kvm_page_track_max_mapping_level(struct kvm *kvm, gfn_t gfn, + enum pg_level max_level) +{ + struct kvm_memory_slot *slot; + int idx; + + idx =3D srcu_read_lock(&kvm->srcu); + slot =3D gfn_to_memslot(kvm, gfn); + if (!slot || slot->flags & KVM_MEMSLOT_INVALID) + max_level =3D PG_LEVEL_4K; + else + max_level =3D kvm_mmu_max_slot_mapping_level(slot, gfn, max_level); + srcu_read_unlock(&kvm->srcu, idx); + + return max_level; +} +EXPORT_SYMBOL_GPL(kvm_page_track_max_mapping_level); diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index d0fca53a3563..6736d7bd94ea 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -1178,14 +1178,22 @@ static int is_2MB_gtt_possible(struct intel_vgpu *v= gpu, struct intel_gvt_gtt_entry *entry) { const struct intel_gvt_gtt_pte_ops *ops =3D vgpu->gvt->gtt.pte_ops; + unsigned long gfn =3D ops->get_pfn(entry); kvm_pfn_t pfn; + int max_level; =20 if (!HAS_PAGE_SIZES(vgpu->gvt->gt->i915, I915_GTT_PAGE_SIZE_2M)) return 0; =20 if (!vgpu->attached) return -EINVAL; - pfn =3D gfn_to_pfn(vgpu->vfio_device.kvm, ops->get_pfn(entry)); + + max_level =3D kvm_page_track_max_mapping_level(vgpu->vfio_device.kvm, + gfn, PG_LEVEL_2M); + if (max_level < PG_LEVEL_2M) + return 0; + + pfn =3D gfn_to_pfn(vgpu->vfio_device.kvm, gfn); if (is_error_noslot_pfn(pfn)) return -EINVAL; =20 --=20 2.39.0.314.g84b9a713c41-goog