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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b2-20020aa79502000000b005cd33628c0fsi878432pfp.177.2023.03.10.16.44.29; Fri, 10 Mar 2023 16:44:46 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=Zpt7qqXU; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230464AbjCKAXo (ORCPT + 99 others); Fri, 10 Mar 2023 19:23:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230118AbjCKAXh (ORCPT ); Fri, 10 Mar 2023 19:23:37 -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 4420E2B298 for ; Fri, 10 Mar 2023 16:23:16 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id lm13-20020a170903298d00b0019a8c8a13dfso3628831plb.16 for ; Fri, 10 Mar 2023 16:23:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1678494195; 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=r49XytvkzC3ENPPvGwyC5xpl4Ljg2/LRKUh4AJANr14=; b=Zpt7qqXUP9P3hTZayirZMVkamUEUKqACeon7oYYD97xhyXG29DKFvc2SehXuaMK1eh 96bAuuC0sdckifi7A5x5BvHjSYp6n5kOQFXB0UoJB1YbHPV06dxE1l1SqnXubOFXmRsK Z85nrGTBFlhudy7NMByKLTHcgoIlcwlw77krq/LeeXJrbT4i1RgCaCjiipszhzOC68N1 Wqgm7NqjACHAxcRBAe/V0X19VDezwBvGmMGY2dfPUEgvNyjcfSdH8o9zcchvrm2jY66q QaFVvRsnIfOiGjSgjPR+aPpZh8DNkEiAG84TgnZaQn3CnSP9MOVs0GtZw+JsxOyoPRG9 pjkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678494195; 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=r49XytvkzC3ENPPvGwyC5xpl4Ljg2/LRKUh4AJANr14=; b=CDBJ4G3tSTaN08bjosI7pC1eQLWPYX0iPI9lNcWdkMeUI1Dm+ryIEoINtJgdNeWvwt NInhWa6pfXgt77jQHTjNZenhuFVHQyv55q11qtn+MBV7uMrOsLgatbXXwG/S0g0PGL62 uhBHL/uQ8S7cLb3j6WUsKLQtRfOiv067kPwx/yO0gQs+hO/kLc4E2B08SL+uflV/mKPO 4SpK8CpRFjDOh4fF5EGDabeYoyt5Ft7JGR6+0TQ+9/5tONW5y2EKDLNcsAIv24KZRpvb HVwWCJBtVlM2Dao07uT0ve09/TeP9VI5cJLKf+TdVonqI6ldKbIURXv7equKA+5xfW7R 1SsQ== X-Gm-Message-State: AO0yUKWlBLXtjJh+KKhR3vABtBjF/EYaoUffHRq2FMjYLxIpIzPyRbpz RsPve3sAa7EpXro+fb+P3FGlVOI7/cI= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:7bc6:b0:22c:2048:794e with SMTP id d6-20020a17090a7bc600b0022c2048794emr10002028pjl.7.1678494195444; Fri, 10 Mar 2023 16:23:15 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 10 Mar 2023 16:22:36 -0800 In-Reply-To: <20230311002258.852397-1-seanjc@google.com> Mime-Version: 1.0 References: <20230311002258.852397-1-seanjc@google.com> X-Mailer: git-send-email 2.40.0.rc1.284.g88254d51c5-goog Message-ID: <20230311002258.852397-6-seanjc@google.com> Subject: [PATCH v2 05/27] drm/i915/gvt: Verify VFIO-pinned page is THP when shadowing 2M 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 X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760030083523978396?= X-GMAIL-MSGID: =?utf-8?q?1760030083523978396?= When shadowing a GTT entry with a 2M page, explicitly verify that the first page pinned by VFIO is a transparent hugepage instead of assuming that page observed by is_2MB_gtt_possible() is the same page pinned by vfio_pin_pages(). E.g. if userspace is doing something funky with the guest's memslots, or if the page is demoted between is_2MB_gtt_possible() and vfio_pin_pages(). This is more of a performance optimization than a bug fix as the check for contiguous struct pages should guard against incorrect mapping (even though assuming struct pages are virtually contiguous is wrong). The real motivation for explicitly checking for a transparent hugepage after pinning is that it will reduce the risk of introducing a bug in a future fix for a page refcount leak (KVMGT doesn't put the reference acquired by gfn_to_pfn()), and eventually will allow KVMGT to stop using KVM's gfn_to_pfn() altogether. Signed-off-by: Sean Christopherson --- drivers/gpu/drm/i915/gvt/kvmgt.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 8ae7039b3683..90997cc385b4 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -159,11 +159,25 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, goto err; } - if (npage == 0) - base_page = cur_page; + if (npage == 0) { + /* + * Bail immediately to avoid unnecessary pinning when + * trying to shadow a 2M page and the host page isn't + * a transparent hugepage. + * + * TODO: support other type hugepages, e.g. HugeTLB. + */ + if (size == I915_GTT_PAGE_SIZE_2M && + !PageTransHuge(cur_page)) + ret = -EIO; + else + base_page = cur_page; + } else if (base_page + npage != cur_page) { gvt_vgpu_err("The pages are not continuous\n"); ret = -EINVAL; + } + if (ret < 0) { npage++; goto err; }