From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9355BC4707C for ; Fri, 12 Jan 2024 19:49:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 210F96B007E; Fri, 12 Jan 2024 14:49:43 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1C0636B0092; Fri, 12 Jan 2024 14:49:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 088936B0099; Fri, 12 Jan 2024 14:49:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id EBA866B007E for ; Fri, 12 Jan 2024 14:49:42 -0500 (EST) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id B5057A24BF for ; Fri, 12 Jan 2024 19:49:42 +0000 (UTC) X-FDA: 81671699004.12.33E1D81 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) by imf22.hostedemail.com (Postfix) with ESMTP id 8C40EC0013 for ; Fri, 12 Jan 2024 19:49:40 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=alien8.de header.s=alien8 header.b=DX0FsTFd; spf=pass (imf22.hostedemail.com: domain of bp@alien8.de designates 65.109.113.108 as permitted sender) smtp.mailfrom=bp@alien8.de; dmarc=pass (policy=none) header.from=alien8.de ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1705088981; a=rsa-sha256; cv=none; b=ebvA2E0wzt8PC/4z9eFOBCZLm5sqw+eQhlo46qqCT+B1JEf6oyis8rnw6ztvWdKUiNyTSf CihOlBkKdTKsaDwM2zf3A6qvkJWQZWEOiaIzQVqC0kpXZ4dxb9c8G2BOpgAz7BwhqHph5w 93v1USYE8OC4ItBaXzycsDfh3rMx1Gs= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=alien8.de header.s=alien8 header.b=DX0FsTFd; spf=pass (imf22.hostedemail.com: domain of bp@alien8.de designates 65.109.113.108 as permitted sender) smtp.mailfrom=bp@alien8.de; dmarc=pass (policy=none) header.from=alien8.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1705088981; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=i7t/gbr0Sua0zSEsqr5ie7pHsjRKCUl3wglMN7YEUCs=; b=fRM0hShngVNAoCZkYdbhNSHdeFwZZ8NLbf49aPeFYAsxIt3g1PtHzma8O2pyvN6OrdO6Ne N4FYPeQIKmSsyWiMNISXtW4AGq3i0IM8u4ReQRQAtllZmOpbIfSW/Imqw5ae6+KS/P2NTs unlvrfFe4LcunQ8mVfVkPhdi1/f4bjk= Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id A48A040E01B2; Fri, 12 Jan 2024 19:49:36 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id imhhkVXVMXrF; Fri, 12 Jan 2024 19:49:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1705088974; bh=i7t/gbr0Sua0zSEsqr5ie7pHsjRKCUl3wglMN7YEUCs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DX0FsTFd61uczDuI00EEc8hfZRLb8OsM3do0ibe0SGqXXPj3x93TQ/l37EENsnPgV EFzlm393Z3Oi4Za9/TN04A52JCzCLtwzDhe9YeXA+8TRmUHRHP3JIRXKdu7wgJvVw9 2unwjYWMvVBew2/YgRhTqM00hDSSVRhYEvNvCIQ8kN2wUdYl82l70w6u9BBbUNHHm4 ihez0Gw1ET0zJt5gVIATaNJsjLKxFj0+0/TwjITurvaKtpkqBir3qd6F4B3MNlSWnB XnfRZuieaBPnRB8pLcH7AUT/HIdxfhacJS09zdyknlJob1/dvkp6dqX3Z/tiJurmfc O6Kx5ZLcyX0Xknu1pvIKnviTBX/S6Tdlt7VY9ff5EYA5dU2N+tyL02UFfrdMgYBNE8 9NcVSYT1EtWupp3EEiedDG7Zsu4Uo+KXIXQJL/wHtyv3xwEtiO5MA+TF6FkBTHGOcH /8ALP4anxGJRe2VWygfdFWtdbBzQHX5AbVmAYBcwAZmhVu+buvUKt5O6pcMcltkTQU Fx1F2jvdZe0so2aEJ+IJC13J2BBnFYd+4TbmeL+qKsC9TI94YsvE3rgV1zHpFP/uDr rUWevP4bgdkcJAZwHsloCvi6ZL3hAPoimXjCyCK11iKGQtgdpr2+VJJDfu8+1ScK2p rI4SZ1VuDPxVKdP+P3pHuNN8= Received: from zn.tnic (pd9530f8c.dip0.t-ipconnect.de [217.83.15.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 9E43B40E00C5; Fri, 12 Jan 2024 19:48:55 +0000 (UTC) Date: Fri, 12 Jan 2024 20:48:49 +0100 From: Borislav Petkov To: Michael Roth Cc: x86@kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com, jmattson@google.com, luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com, pgonda@google.com, peterz@infradead.org, srinivas.pandruvada@linux.intel.com, rientjes@google.com, tobin@ibm.com, vbabka@suse.cz, kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com, pankaj.gupta@amd.com, liam.merwick@oracle.com, zhi.a.wang@intel.com, Brijesh Singh Subject: Re: [PATCH v1 11/26] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Message-ID: <20240112194849.GDZaGXoTeYkx3GYSsQ@fat_crate.local> References: <20231230161954.569267-1-michael.roth@amd.com> <20231230161954.569267-12-michael.roth@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231230161954.569267-12-michael.roth@amd.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 8C40EC0013 X-Stat-Signature: gku85sm3ztc6sud1no6z9ukxgyffr6rg X-Rspam-User: X-HE-Tag: 1705088980-985591 X-HE-Meta: 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 7x/QhCR8 iugFKh5LO1t7eDYgawm4/tcIIkP4OJQIKoMZppV15eFfHr1Ynx6z4Z308vIZareQQ8IeLwn3hilm6DlNNM6Du9O4B0vuFx/B+CU9E0zxld5wqHJ4ANXHq9X14eViu7xRlxohXIcnFx8qWzOw9Rb6MOkiRLiW3JiAwod5AkWI/NO0A85DUCU5yJBHyxz7pbIwl4ziz7GHhUDmDMLs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Dec 30, 2023 at 10:19:39AM -0600, Michael Roth wrote: > static int rmpupdate(u64 pfn, struct rmp_state *state) > { > unsigned long paddr = pfn << PAGE_SHIFT; > - int ret; > + int ret, level, npages; > > if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) > return -ENODEV; > > + level = RMP_TO_PG_LEVEL(state->pagesize); > + npages = page_level_size(level) / PAGE_SIZE; > + > + /* > + * If the kernel uses a 2MB directmap mapping to write to an address, > + * and that 2MB range happens to contain a 4KB page that set to private > + * in the RMP table, an RMP #PF will trigger and cause a host crash. > + * > + * Prevent this by removing pages from the directmap prior to setting > + * them as private in the RMP table. > + */ > + if (state->assigned && invalidate_direct_map(pfn, npages)) > + return -EFAULT; Well, the comment says one thing but the code does not do quite what the text says: * where is the check that pfn is part of the kernel direct map? * where is the check that this address is part of a 2M PMD in the direct map so that the situation is even given that you can have a 4K private PTE there? What this does is simply invalidate @npages unconditionally. Then, __set_pages_np() already takes a number of pages and a start address. Why is this thing iterating instead of sending *all* npages in one go? Yes, you'd need two new helpers, something like: set_pages_present(struct page *page, int numpages) set_pages_non_present(struct page *page, int numpages) which call the lowlevel counterparts. For some reason I remember asking this a while ago... -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette