From patchwork Thu Oct 13 21:12:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13006413 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 EEB3DC433FE for ; Thu, 13 Oct 2022 21:13:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229720AbiJMVNH (ORCPT ); Thu, 13 Oct 2022 17:13:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229972AbiJMVNA (ORCPT ); Thu, 13 Oct 2022 17:13:00 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32DC21905FC for ; Thu, 13 Oct 2022 14:12:51 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id px13-20020a17090b270d00b0020aa188aae8so1611311pjb.8 for ; Thu, 13 Oct 2022 14:12:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=uc8kmmFZoUXqBTWy4jGsXZWgvRttVIt6U3EgjEmEwRI=; b=G/kNW6cLiqJ/v9Od1bnKW68lrKo88d/zdCSp6txQE7w/+YvpLfpj6f9TCnNHIYWph+ TaPXLjRugOqs4htlRkaN1cJ0T3TwMZpkb079IXz/ysiXBOCciuMdQ5L0LFxbKzeEVdA+ 2WJwiWCFD/CI8QvPvbSbX6oLKhoFz073GMOB0bZrS8zik0+XRLhvix4nj89uVMjEYKmv J9Lh9rcHypVfUzL+7Npa3bqEWkzo0rkEI1e20AKt5EDK5OZeCHQRLO6IXg7AWxTP6fNP Xw/GTONzLvgCZSInFFAsctUYIFeDRH3mrv07KKGP2rbBmzaw7SHOFRuPJXJk7bzLC4du ZQgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uc8kmmFZoUXqBTWy4jGsXZWgvRttVIt6U3EgjEmEwRI=; b=hFcBXOqxqey2csS5tOF2twyyakizeNXrURIxB6oHFAmkRZc314K3CqW+4Czxaya1KC FEFa4D0sDQkTU0KjQZ0vDBrtx1HS4ntP97vVRWjO9U643WU01CA5IyfOpIzmLcMS1vLO 7FV5c78PVIJDgt7hDL+nRWXIXF54A3GGh7bRixOW4u87n4QS8M2xJ1DLbU/7xKW4eHOf Iqww5OgFK6NPuPHBJk6KzPkfz6TxR04a9ZOnYDov+E16Ba2rfDpKXM2PJXxuHZfUEZ7N uODqnNDxZ4d99KmCM2fbhfJwbv8y8wKwY6TUsFLVGYLw/p8Haasvan1zCuUI40vNkB2n 6zTA== X-Gm-Message-State: ACrzQf3Fef1GemsQToZcNcPHKK1cuktRLN+ZsDhsDVe0c1SFUM7Ieqn0 Sf0LEAlsGeiE4MMYay0pyNXp9LXuKn0= X-Google-Smtp-Source: AMsMyM6lfBV+A6iTM7o+iwJYvIz2bHF1gq60ZCkj5I0cee9Gh6Ot9beWiHpM8SrReoW+X7Val4T2yNQn6zo= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90b:4c4f:b0:20d:4f5d:6b7c with SMTP id np15-20020a17090b4c4f00b0020d4f5d6b7cmr13508911pjb.77.1665695559312; Thu, 13 Oct 2022 14:12:39 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 13 Oct 2022 21:12:18 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.0.413.g74048e4d9e-goog Message-ID: <20221013211234.1318131-1-seanjc@google.com> Subject: [PATCH v2 00/16] KVM: x86: gfn_to_pfn_cache fixes and cleanups From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Luczaj , David Woodhouse Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The highlights are two fixes for bugs where "destroying" and "initializing" a gfn=>pfn cache while it is being accessed results in various forms of badness, e.g. re-initialization of an in-use lock, consuming a NULL pointer, potential memory corruption, etc... Everything else is cleanup to make the gpc APIs easier to use and harder to use incorrectly. David, patch 3 (KVM: x86: Always use non-compat vcpu_runstate_info size...) in particular needs your eyeballs. I'm pretty sure it's ok, but confirmation from someone that actually uses KVM XEN would be nice. v2: - Fix active vs. valid race by rejecting refresh() if the cache is currently invalid. - Tweak shortlogs to be "KVM" only. Even though x86 is the only user of the caches, I think it makes sense to tag the changes as "full" KVM for future readers. - Add back the selftest (from the RFC) that triggers the race conditions. - Always use non-compat size for checking+refreshing runstate_info and make @len truly immutable. - Drop unmap() for the moment. I started adding code to prevent "bad" usage, but without any user I couldn't figure out exactly what restrictions need to be in place. - Do more cleanup. v1: https://lore.kernel.org/all/20220921020140.3240092-1-mhal@rbox.co Michal Luczaj (9): KVM: Initialize gfn_to_pfn_cache locks in dedicated helper KVM: Shorten gfn_to_pfn_cache function names KVM: x86: Remove unused argument in gpc_unmap_khva() KVM: Store immutable gfn_to_pfn_cache properties KVM: Store gfn_to_pfn_cache length as an immutable property KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_check() KVM: Clean up hva_to_pfn_retry() KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_refresh() KVM: selftests: Add tests in xen_shinfo_test to detect lock races Sean Christopherson (7): KVM: Reject attempts to consume or refresh inactive gfn_to_pfn_cache KVM: x86: Always use non-compat vcpu_runstate_info size for gfn=>pfn cache KVM: Drop KVM's API to allow temprorarily unmapping gfn=>pfn cache KVM: Do not partially reinitialize gfn=>pfn cache during activation KVM: Drop @gpa from exported gfn=>pfn cache check() and refresh() helpers KVM: Skip unnecessary "unmap" if gpc is already valid during refresh KVM: selftests: Mark "guest_saw_irq" as volatile in xen_shinfo_test arch/x86/kvm/x86.c | 24 +-- arch/x86/kvm/xen.c | 84 ++++----- include/linux/kvm_host.h | 73 ++++---- include/linux/kvm_types.h | 2 + .../selftests/kvm/x86_64/xen_shinfo_test.c | 142 ++++++++++++++- virt/kvm/pfncache.c | 170 ++++++++++-------- 6 files changed, 320 insertions(+), 175 deletions(-) base-commit: e18d6152ff0f41b7f01f9817372022df04e0d354