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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-390cd8fbef5sm5529678f8f.90.2025.02.26.03.52.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Feb 2025 03:52:28 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 27825486-f438-11ef-9897-31a8f345e629 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1740570748; x=1741175548; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=EMk5+NKhGum3QtmdtmnLKhjInNSavSN0lNc/5reLNog=; b=MA/TutLZ+PRn+HgHd0k0rZZ+Eqte0w02VL4r1aQAso6FWeOcBpcUt2Y0syArZKtsCy emVGWqdIWKFWZBaNXcm/GNsCKA157GSC3r44HJSr41KsDjBcSLQ1koncJFUcw4WsKoMl rnpPo7NgLXxenShX/00vx6A8ZZHTtNdxm8xt8IG64XlmtLKiNVC48crmGuBQN5SxosNc zTJ0DI2mBJxcxkx0kvxCnkJTls8M0dmFqEziZB5yqaqjcPpRtp16PIqOAlLfLTJ7wqOV M8INH4Z3YcvMXbAcIJjBFY9AejwcWyiJI3abzUEd4XHN0zDqrA+R1FRn2UMC78J7tTEO XkIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740570748; x=1741175548; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=EMk5+NKhGum3QtmdtmnLKhjInNSavSN0lNc/5reLNog=; b=hmZLs72lcIW/tlIqZ/V5Nm7w21pyGdvtFM1Q04scVNOg6sxkhvSjoOdn5WJwFlL2Bu 5ZXWVJhS1B+H5IYj3ifr28rXaSNj2RDyYWNC9n6sSCM5VLcmYExwMRoZzuOMGqtXP/vS tdsRl0QOYnFeMSafIynrExKytc17NuEU13BVl/bfp/QkClE9Qx9O9waKqhGtp8LJ+JiC YkJttKv1Y8wA+MWJayBYTd5+oGzzx1XGbrU1oeM7SlSPqi13ySLM2rFa54MKjBvOEg4q ZNrHRgHiL3P/sq3jMG6pqbofzUbpwq0VwQj/iK8gaeHn63KraStCUNfCl9nwCl7Rgwf3 +C7A== X-Gm-Message-State: AOJu0Yyi5WT968VaQaOvQqyjhCNMEMcAgenAvprDZMUJkDvXE0RQzBFD wAqwwFBqJ5ae2w2yg0REhBvqutJuWhdXHdERE56Lc/pzU6/9mTtqX/tmfd4F8RG5Hs7KIRW+sMQ = X-Gm-Gg: ASbGncuyPsuwNqYPqjabWNCDjD8wheqOAU35hJYRGFBRrh6/Q7LYQ4cxHOlDRTXiYWG k93LyHi8A2qsB+JAgFjICsEQn2dauh92GeDMMZEBYwmwlXB9F3Msc9I23E+ez507QIumiPLN2qf m15WR+fD41q0mhriki7fLfdYke7WPH2qstP3LpIKHbY4W2nlq+Hazc3NPQe4GmvZb3W6GrcP23g WzqJfEyjRhsEaNGZeYiTLiv07z7DkwsUEK0rYWIyLUQE382X+LuYX1scn9i5gBlPBMMdxrBagL0 jsZi/w7o8os/vZe8lWceMVzW2otvtlKhC6GqnKmJCLBtt+PT02FAupirzKNe0JjHiD7JWagtJE9 9GofqXTLCp+0= X-Google-Smtp-Source: AGHT+IHQY7RTeKP0ltTVsquDyu/YAHdfXAHfnqDyZUcwG+GP+QTT79o/6RilxPQzaRalIBCNcvYIag== X-Received: by 2002:a05:6000:178f:b0:38f:2073:1493 with SMTP id ffacd0b85a97d-38f70789bedmr14073315f8f.15.1740570748568; Wed, 26 Feb 2025 03:52:28 -0800 (PST) Message-ID: <88d24595-50be-4f99-97d6-9126340b791e@suse.com> Date: Wed, 26 Feb 2025 12:52:27 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH 1/3] x86/P2M: synchronize fast and slow paths of p2m_get_page_from_gfn() From: Jan Beulich To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , =?utf-8?q?Roger_Pau_Monn?= =?utf-8?q?=C3=A9?= References: <7363b2ee-f297-4b0b-9c4d-bdebe08d514b@suse.com> Content-Language: en-US Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: <7363b2ee-f297-4b0b-9c4d-bdebe08d514b@suse.com> Handling of both grants and foreign pages was different between the two paths. While permitting access to grants would be desirable, doing so would require more involved handling; undo that for the time being. In particular the page reference obtained would prevent the owning domain from changing e.g. the page's type (after the grantee has released the last reference of the grant). Instead perhaps another reference on the grant would need obtaining. Which in turn would require determining which grant that was. Foreign pages in any event need permitting on both paths. Introduce a helper function to be used on both paths, such that respective checking differs in just the extra "to be unshared" condition on the fast path. While there adjust the sanity check for foreign pages: Don't leak the reference on release builds when on a debug build the assertion would have triggered. (Thanks to Roger for the suggestion.) Fixes: 80ea7af17269 ("x86/mm: Introduce get_page_from_gfn()") Fixes: 50fe6e737059 ("pvh dom0: add and remove foreign pages") Fixes: cbbca7be4aaa ("x86/p2m: make p2m_get_page_from_gfn() handle grant case correctly") Signed-off-by: Jan Beulich --- RFC: While the helper could take const struct domain * as first parameter, for a P2M function it seemed more natural to have it take const struct p2m_domain *. --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -328,12 +328,45 @@ void p2m_put_gfn(struct p2m_domain *p2m, gfn_unlock(p2m, gfn_x(gfn), 0); } +static struct page_info *get_page_from_mfn_and_type( + const struct p2m_domain *p2m, mfn_t mfn, p2m_type_t t) +{ + struct page_info *page; + + if ( !mfn_valid(mfn) ) + return NULL; + + page = mfn_to_page(mfn); + + if ( p2m_is_ram(t) ) + { + const struct domain *d = !p2m_is_shared(t) ? p2m->domain : dom_cow; + + if ( get_page(page, d) ) + return page; + } + else if ( unlikely(p2m_is_foreign(t)) ) + { + const struct domain *fdom = page_get_owner_and_reference(page); + + if ( fdom ) + { + if ( likely(fdom != p2m->domain) ) + return page; + ASSERT_UNREACHABLE(); + put_page(page); + } + } + + return NULL; +} + /* Atomically look up a GFN and take a reference count on the backing page. */ struct page_info *p2m_get_page_from_gfn( struct p2m_domain *p2m, gfn_t gfn, p2m_type_t *t, p2m_access_t *a, p2m_query_t q) { - struct page_info *page = NULL; + struct page_info *page; p2m_access_t _a; p2m_type_t _t; mfn_t mfn; @@ -347,26 +380,9 @@ struct page_info *p2m_get_page_from_gfn( /* Fast path: look up and get out */ p2m_read_lock(p2m); mfn = p2m_get_gfn_type_access(p2m, gfn, t, a, 0, NULL, 0); - if ( p2m_is_any_ram(*t) && mfn_valid(mfn) - && !((q & P2M_UNSHARE) && p2m_is_shared(*t)) ) - { - page = mfn_to_page(mfn); - if ( unlikely(p2m_is_foreign(*t)) || unlikely(p2m_is_grant(*t)) ) - { - struct domain *fdom = page_get_owner_and_reference(page); - - ASSERT(!p2m_is_foreign(*t) || fdom != p2m->domain); - if ( fdom == NULL ) - page = NULL; - } - else - { - struct domain *d = !p2m_is_shared(*t) ? p2m->domain : dom_cow; - - if ( !get_page(page, d) ) - page = NULL; - } - } + page = !(q & P2M_UNSHARE) || !p2m_is_shared(*t) + ? get_page_from_mfn_and_type(p2m, mfn, *t) + : NULL; p2m_read_unlock(p2m); if ( page ) @@ -380,14 +396,7 @@ struct page_info *p2m_get_page_from_gfn( /* Slow path: take the write lock and do fixups */ mfn = get_gfn_type_access(p2m, gfn_x(gfn), t, a, q, NULL); - if ( p2m_is_ram(*t) && mfn_valid(mfn) ) - { - struct domain *d = !p2m_is_shared(*t) ? p2m->domain : dom_cow; - - page = mfn_to_page(mfn); - if ( !get_page(page, d) ) - page = NULL; - } + page = get_page_from_mfn_and_type(p2m, mfn, *t); put_gfn(p2m->domain, gfn_x(gfn)); return page; From patchwork Wed Feb 26 11:52:45 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 13992165 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 251F9C021BF for ; Wed, 26 Feb 2025 11:53:05 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.896446.1305152 (Exim 4.92) (envelope-from ) id 1tnFy5-00072E-EB; Wed, 26 Feb 2025 11:52:49 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 896446.1305152; Wed, 26 Feb 2025 11:52:49 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tnFy5-000727-Bc; Wed, 26 Feb 2025 11:52:49 +0000 Received: by outflank-mailman (input) for mailman id 896446; Wed, 26 Feb 2025 11:52:47 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tnFy3-0006xM-FB for xen-devel@lists.xenproject.org; Wed, 26 Feb 2025 11:52:47 +0000 Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [2a00:1450:4864:20::329]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 3206f476-f438-11ef-9aae-95dc52dad729; Wed, 26 Feb 2025 12:52:46 +0100 (CET) Received: by mail-wm1-x329.google.com with SMTP id 5b1f17b1804b1-43995b907cfso42149855e9.3 for ; Wed, 26 Feb 2025 03:52:46 -0800 (PST) Received: from [10.156.60.236] (ip-037-024-206-209.um08.pools.vodafone-ip.de. [37.24.206.209]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43aba58717esm18582625e9.33.2025.02.26.03.52.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Feb 2025 03:52:45 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3206f476-f438-11ef-9aae-95dc52dad729 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1740570766; x=1741175566; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=B5K3ghHFEUKY+Sz/+pAKS3KKwzSv5cNIOym7K1d3bOs=; b=VRZArgkDJEKoSgJBzRlDSTsPOxf44Bu4WLFfn/CCBw01KUtfictj5gmXK6BkWTRpzs UPW+ltGgwbyW6Vzi4VdEQXAqYG2mGg6dVEmGqN7P/YrgyzokUHuiVRKbfShlsNddcDNT 7r0M+HWC13m6QYg2mWUleB2CwdBcz4S3m+WJj0ACZRXP5fKJF89YH6tBQCSSqprqCRmG 5JX775t5jqd4OQI5/n3s5ZbNrOIUMxFs8w07lNPqlQbe892qJxlqa4yqsaFN+a9Y9jcR LynAn3u9YAQTF5cJ/CRwTAL5PWcPzNl+xqlII2Ey2ZBoby/lNE99KrLSa6mYTzay83oQ rojA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740570766; x=1741175566; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=B5K3ghHFEUKY+Sz/+pAKS3KKwzSv5cNIOym7K1d3bOs=; b=pXFg+403KFDwwtKe04Kb2IijJsIgI9iYMnswztdY4DGM576UPZz8ssVrxVWGhMn7rj bp2G3rh9P6wQt/I+ItNdp2STSLQyD9b8p7hhMhIyMYPUjUNUhPcs3DaF0YiK5pU9py1O 3DAtPF481QHZo8qxvkZFke1TX9H+1fEwYeAfpwfb9TlyFAwJtaP8MuhwmkQsygWTtQXx v6PddB/Yty8l4J2tKUujJUuKizBqDOG6bR8S2g98Ylte2LJicl+uvBNMsyl8Q7RvQAS0 QOvPIa040xPNtlhbL5Ibfx1a3VyjPuqex0WFA8xC/xMGWaw7ZJcH7nGZfYABlbuwLKH2 Z7rw== X-Gm-Message-State: AOJu0Yzd/bq1rYVlCwgcHYJQsowA/ntxUqmafldb9AzO4D+5rMZtPI8Q uaZJqWNUyZVRVl17JLLU6+WpPT/Uu7HRVUgKIgudyyDLrdHtCkA1XPwGPo1dt4rThwkWg6ziN2U = X-Gm-Gg: ASbGnctaOLA3csd+n/VDOC/I5s+aNrCpjIvKa236tZ4odh3DaUvawj0NhM/LlgpFv84 nvL3cnDqB2C7BOixv3wPxezoGeUuv5wAf3jJyTqpOtrh7Tjw6VX5pWH+bDURScCWWH6R110Azx3 FtdRvn+smfhOLDJ4WM7Kdvs/j/XTFEM8lMgWo1iYLC5oGgV+D5Hcxb148ZD4pKGVwjzjkikwdVo gp7M2bAbf3ajgerSFdeV1b5wI1GfwBEkrmd3630mZEfe7EyFNeW3L4LJ6b+EKKUJRa/OtvlUXhu QybIudN6iGFIU2KewQSVcqIEnsxnU0avkNK+66All3jqm81DdRwjNtdfG/bGTxU55S7xW+rv293 YHzelCT96PIQ= X-Google-Smtp-Source: AGHT+IFTuewJz5fhC4vpqLMOtQdq/QdU6EVL5Gara2b45wJ1k4losOmf7IZxfAqfCyOdRM6qO9nlFA== X-Received: by 2002:adf:ffc8:0:b0:38f:4d91:c123 with SMTP id ffacd0b85a97d-390cc60cf53mr4504063f8f.32.1740570766214; Wed, 26 Feb 2025 03:52:46 -0800 (PST) Message-ID: Date: Wed, 26 Feb 2025 12:52:45 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH 2/3] x86/P2M: correct old entry checking in p2m_remove_entry() From: Jan Beulich To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , =?utf-8?q?Roger_Pau_Monn?= =?utf-8?q?=C3=A9?= References: <7363b2ee-f297-4b0b-9c4d-bdebe08d514b@suse.com> Content-Language: en-US Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: <7363b2ee-f297-4b0b-9c4d-bdebe08d514b@suse.com> Using p2m_is_valid() isn't quite right here. It expanding to RAM+MMIO, the subsequent p2m_mmio_direct check effectively reduces its use to RAM+MMIO_DM. Yet MMIO_DM entries, which are never marked present in the page tables, won't pass the mfn_valid() check. It is, however, quite plausible (and supported by the rest of the function) to permit "removing" hole entries, i.e. in particular to convert MMIO_DM to INVALID. Which leaves the original check to be against RAM (plus MFN validity), while HOLE then instead wants INVALID_MFN to be passed in. Further more grant and foreign entries (together with RAM becoming ANY_RAM) as well as BROKEN want the MFN checking, too. All other types (i.e. MMIO_DIRECT and POD) want rejecting here rather than skipping, for needing handling / accounting elsewhere. Signed-off-by: Jan Beulich --- Paging/sharing types likely need further customization here. Paths leading here differ in their handling (e.g. guest_remove_page() special- casing paging types vs XENMEM_remove_from_physmap not doing so), so it's not even clear what the intentions are for those types. --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -531,9 +531,9 @@ p2m_remove_entry(struct p2m_domain *p2m, mfn_t mfn_return = p2m->get_entry(p2m, gfn_add(gfn, i), &t, &a, 0, &cur_order, NULL); - if ( p2m_is_valid(t) && - (!mfn_valid(mfn) || t == p2m_mmio_direct || - !mfn_eq(mfn_add(mfn, i), mfn_return)) ) + if ( p2m_is_any_ram(t) || p2m_is_broken(t) + ? !mfn_valid(mfn) || !mfn_eq(mfn_add(mfn, i), mfn_return) + : !p2m_is_hole(t) || !mfn_eq(mfn, INVALID_MFN) ) return -EILSEQ; i += (1UL << cur_order) - From patchwork Wed Feb 26 11:53:14 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 13992166 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B54A9C021B8 for ; Wed, 26 Feb 2025 11:53:30 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.896460.1305162 (Exim 4.92) (envelope-from ) id 1tnFyY-0007hI-Nn; Wed, 26 Feb 2025 11:53:18 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 896460.1305162; Wed, 26 Feb 2025 11:53:18 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tnFyY-0007hB-Kr; Wed, 26 Feb 2025 11:53:18 +0000 Received: by outflank-mailman (input) for mailman id 896460; Wed, 26 Feb 2025 11:53:17 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tnFyX-0006xM-0I for xen-devel@lists.xenproject.org; Wed, 26 Feb 2025 11:53:17 +0000 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [2a00:1450:4864:20::430]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 43257d6d-f438-11ef-9aae-95dc52dad729; Wed, 26 Feb 2025 12:53:15 +0100 (CET) Received: by mail-wr1-x430.google.com with SMTP id ffacd0b85a97d-390d6426f1bso338799f8f.2 for ; Wed, 26 Feb 2025 03:53:15 -0800 (PST) Received: from [10.156.60.236] (ip-037-024-206-209.um08.pools.vodafone-ip.de. [37.24.206.209]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-390cd8e7121sm5377361f8f.61.2025.02.26.03.53.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Feb 2025 03:53:14 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 43257d6d-f438-11ef-9aae-95dc52dad729 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1740570795; x=1741175595; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=7P5C2APSwoFZMq5J+tFruta/TZatKK4sGBr/+R4Wqn4=; b=C0UtWShowlZep7wnBJFiVMzEHVSq6yc4EdsgHb7wIvOksiKdIABMOvufCz5pBIV5UO qTvWrGARDt/nnHb1+asav7S4UJ6Vp/mYnaVhw49qv6TL2FGlTpIaI8iyMe9v34pIW2zH CmZ96UFZXG27eAni8MHRckE0MiyFBGwTrKhUNQ3NGEePj85f6b2CpoECUlxodAN3zGW4 atdacHYxs0u+EapZ1m3rl4hxHz3MpnI0DVEE7jEfLagJ8RJV8se6kbPrVPtx/tTDN0gq kxC2bz3m9RgbzhrD5GRuvWhn9b9nN7XdCVzbPx7ukj7puy8HWMAqCGL8nQ2teloY4HjU 86cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740570795; x=1741175595; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=7P5C2APSwoFZMq5J+tFruta/TZatKK4sGBr/+R4Wqn4=; b=frhKcUeNAZMFNLyCSvV28KtkxJWJDWJzUz3giqLHotVDRL9wLYLn6fPISR1Pf6qJQx mh4XR92De9GjsaoCtw/ZHns/GIgDMhSvCX6/4NYr9SAz2Qjl85dJdS5/YbCgooe8i/ZM Mi2l5kmCdYe+U9GVy6UEXnDXY8bwdBxjE4XtbREy8JGZWyIAb0jjHQ5H6yarc2Fkx9Zw gjYDN/4svOw9kh0LFunxn7yeEPvgwHt5C9Iy/2i/hBoxdSrBa1PivZmM0/jXJL+o+AEl M5FwXeA0iCfr1eS85vv66O7feEKX0mMC30rd51QJXZUmxxngbCD+vD0lJqJ+fYO+6uM4 7lOQ== X-Gm-Message-State: AOJu0Yw9Xvnb+sioR7gWqE8mDNde1JfIB4yCIrU7CUMSpEwBy4A91fmw 6yyTJc/BOWHznK3oC2MA8D1GZGrv0BDf7WNCwcYKIcnQImMzeNjfltntu95axBgdBwEwpd/FgO4 = X-Gm-Gg: ASbGncuI6NfLhUVsmnGOuUKDzl2UErRjYIGvVV6aj2nqxM+akJplmCx455UoiGzkkAx DbpJHiMEX7yzOQpfbPejiCqzFPWMkW82WNYmhdLawoywXZ7udVCRc+s16NS8H0JFoTE04Hl8i3O fETRwzEx5s+KWL/1ya/NKaRmYHGUDMaO+f2TXAuvZUjKAILjWo2zPHOzD9+oBut5j/O8Hoy26PW ZXjFo1OhaM5fznR7fMWH0u/Pe8u5FzhwX2bBxIE+4uXmqTzqfiNjOi+FqaKRZh7NFwd0nUS/V1Y 2KRH2OFE6JA4avrcMkyf9xaB96ubS/mDk0rqrI9FFtV4KfIh6ykdRZdvNrAUuxoZSM1No6RSp39 RwDKGG8XLWJ4= X-Google-Smtp-Source: AGHT+IGBWKScsf+3TQwRVP/ld+kKdLzZlQGdSV1MHSo14ss+v2qgw4sfLLN3sNF0XTgTCyteEUy6EQ== X-Received: by 2002:a5d:6d82:0:b0:38f:2b49:7bfe with SMTP id ffacd0b85a97d-38f6f0ae7eamr19788694f8f.47.1740570794950; Wed, 26 Feb 2025 03:53:14 -0800 (PST) Message-ID: <2c9885d4-4a9f-4998-b0fa-15c17115fa1e@suse.com> Date: Wed, 26 Feb 2025 12:53:14 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH 3/3] x86/P2M: don't include MMIO_DM in p2m_is_valid() From: Jan Beulich To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , =?utf-8?q?Roger_Pau_Monn?= =?utf-8?q?=C3=A9?= References: <7363b2ee-f297-4b0b-9c4d-bdebe08d514b@suse.com> Content-Language: en-US Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: <7363b2ee-f297-4b0b-9c4d-bdebe08d514b@suse.com> MMIO_DM specifically marks pages which aren't valid, much like INVALID does. Dropping the type from the predicate - (conceptually) corrects _sh_propagate(), where the comment says that "something valid" is needed (the only call path not passing in RAM_RW would pass in INVALID_GFN along with MMIO_DM), - is benign to the use in sh_page_fault(), where the subsequent mfn_valid() check would otherwise cause the same bail-out code path to be taken, - is benign to all three uses in p2m_pt_get_entry(), as MMIO_DM entries will only ever yield non-present entries, which are being checked for earlier, - is benign to sh_unshadow_for_p2m_change(), for the same reason, - is benign to gnttab_transfer() with EPT not in use, again because MMIO_DM entries will only ever yield non-present entries, and INVALID_MFN is returned for those anyway by p2m_pt_get_entry(). - for gnttab_transfer() with EPT in use (conceptually) corrects the corner case of a page first being subject to XEN_DMOP_set_mem_type converting a RAM type to MMIO_DM (which retains the MFN in the entry), and then being subject to GNTTABOP_transfer, except that steal_page() would later make the operation fail unconditionally anyway. While there also drop the unused (and otherwise now redundant) p2m_has_emt(). Signed-off-by: Jan Beulich --- a/xen/arch/x86/include/asm/p2m.h +++ b/xen/arch/x86/include/asm/p2m.h @@ -168,8 +168,8 @@ typedef unsigned int p2m_query_t; /* Grant types are *not* considered valid, because they can be unmapped at any time and, unless you happen to be the shadow or p2m implementations, there's no way of synchronising against that. */ -#define p2m_is_valid(_t) (p2m_to_mask(_t) & (P2M_RAM_TYPES | P2M_MMIO_TYPES)) -#define p2m_has_emt(_t) (p2m_to_mask(_t) & (P2M_RAM_TYPES | p2m_to_mask(p2m_mmio_direct))) +#define p2m_is_valid(_t) (p2m_to_mask(_t) & \ + (P2M_RAM_TYPES | p2m_to_mask(p2m_mmio_direct))) #define p2m_is_pageable(_t) (p2m_to_mask(_t) & P2M_PAGEABLE_TYPES) #define p2m_is_paging(_t) (p2m_to_mask(_t) & P2M_PAGING_TYPES) #define p2m_is_paged(_t) (p2m_to_mask(_t) & P2M_PAGED_TYPES)