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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4532C88CB2 for ; Thu, 24 Aug 2023 08:06:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239010AbjHXIFi (ORCPT ); Thu, 24 Aug 2023 04:05:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240489AbjHXIFY (ORCPT ); Thu, 24 Aug 2023 04:05:24 -0400 Received: from mail-oi1-x22b.google.com (mail-oi1-x22b.google.com [IPv6:2607:f8b0:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54601170E for ; Thu, 24 Aug 2023 01:04:51 -0700 (PDT) Received: by mail-oi1-x22b.google.com with SMTP id 5614622812f47-3a8036d805eso4747577b6e.3 for ; Thu, 24 Aug 2023 01:04:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1692864289; x=1693469089; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=5EE+UzoRngnjehf25g1txAUD7jFYvBFO8xVG5NUnepk=; b=PiabMMQhe9y2vUBAt7h+ntRdrItXl5XEmXNUAkQzHdz/5Usah2vUewJPe1DxJjyMoj MPwJ8vBC0PRuHBzkM99uP/8pDt3bKa4MMVAyZvrVMT5+kHkXevDD6Xbkw9rXNNage966 g+94vbQfs3rPzxqPbviDDzoC4v8GyCo9zgfVo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692864289; x=1693469089; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=5EE+UzoRngnjehf25g1txAUD7jFYvBFO8xVG5NUnepk=; b=mH+xDbZNWZLaJ6TsCKFcj5RZdij3dayzWTFD08QjRtQgdy5sKgXk7OnY47paBrEYAB Im1aaTRtbZqevawBbtwhF/K53FM0rhEM67cguuE0A0qyDarBsc2aytMh19xzz8dpXJCR AQTPdi1oQMemYXcZwMwhtHz/ixUDpTAccBBX98J7Io2AE/iN38dwOI+xDNBS+BLy1yGT dhUCznb4jOpr9ohkdzFeLN7PUToow0ZBy1cIe8L9bZoIpa3wftEp8IsGqssKVtFVhdlT n/9wvzVce5W6ZygN+Ere+5vjnK3Z6sXj3tayVRd1d9goQ5ME0SxCfZ2cGJUATTTGyTSB q6DQ== X-Gm-Message-State: AOJu0YzW9Vg77vHTF01FSBkMS/7aSk1NmUJHIBT/t4OXjO8v5yp0uRds t1BM2zIjf41T9hOnTTPCZcs+kg== X-Google-Smtp-Source: AGHT+IHkBcWKFj3+pW5fuuiWfLnbD3ta+ABypKF47WzCDkfdw67HWPAGK/Ns2WRoKXuxgQGkt6DXAw== X-Received: by 2002:a05:6358:720c:b0:13c:c84b:88bb with SMTP id h12-20020a056358720c00b0013cc84b88bbmr2497118rwa.27.1692864289233; Thu, 24 Aug 2023 01:04:49 -0700 (PDT) Received: from localhost ([2401:fa00:8f:203:515:8b2a:90c3:b79e]) by smtp.gmail.com with UTF8SMTPSA id a18-20020aa78652000000b00666e649ca46sm7014327pfo.101.2023.08.24.01.04.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Aug 2023 01:04:48 -0700 (PDT) From: David Stevens X-Google-Original-From: David Stevens To: Sean Christopherson Cc: Yu Zhang , Isaku Yamahata , Marc Zyngier , Michael Ellerman , Peter Xu , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, David Stevens Subject: [PATCH v8 0/8] KVM: allow mapping non-refcounted pages Date: Thu, 24 Aug 2023 17:04:00 +0900 Message-ID: <20230824080408.2933205-1-stevensd@google.com> X-Mailer: git-send-email 2.42.0.rc1.204.g551eb34607-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Stevens This patch series adds support for mapping VM_IO and VM_PFNMAP memory that is backed by struct pages that aren't currently being refcounted (e.g. tail pages of non-compound higher order allocations) into the guest. Our use case is virtio-gpu blob resources [1], which directly map host graphics buffers into the guest as "vram" for the virtio-gpu device. This feature currently does not work on systems using the amdgpu driver, as that driver allocates non-compound higher order pages via ttm_pool_alloc_page. First, this series replaces the __gfn_to_pfn_memslot API with a more extensible __kvm_faultin_pfn API. The updated API rearranges __gfn_to_pfn_memslot's args into a struct and where possible packs the bool arguments into a FOLL_ flags argument. The refactoring changes do not change any behavior, except as noted in the PPC change. When introduced in the refactoring, __kvm_faultin_pfn implies FOLL_GET to preserve existing behavior. From there, the API is made to support mapping non-refcounted pages by respecting the FOLL_GET flag. This series only adds support for non-refcounted pages to the x86 MMU. Other MMUs can likely be updated without too much difficulty, but it is not needed at this point. Updating other parts of KVM (e.g. pfncache) is not straightforward [2]. [1] https://patchwork.kernel.org/project/dri-devel/cover/20200814024000.2485-1-gurchetansingh@chromium.org/ [2] https://lore.kernel.org/all/ZBEEQtmtNPaEqU1i@google.com/ v7 -> v8: - Set access bits before releasing mmu_lock. - Pass FOLL_GET on 32-bit x86 or !tdp_enabled. - Refactor FOLL_GET handling, add kvm_follow_refcounted_pfn helper. - Set refcounted bit on >4k pages. - Add comments and apply formatting suggestions. - rebase on kvm next branch. v6 -> v7: - Replace __gfn_to_pfn_memslot with a more flexible __kvm_faultin_pfn, and extend that API to support non-refcounted pages. v5 -> v6: - rebase on kvm next branch - rename gfn_to_pfn_page to gfn_to_pfn_noref - fix uninitialized outparam in error case of __kvm_faultin_pfn - add kvm_release_pfn_noref_clean for releasing pfn/page pair v4 -> v5: - rebase on kvm next branch again v3 -> v4: - rebase on kvm next branch again - Add some more context to a comment in ensure_pfn_ref v2 -> v3: - rebase on kvm next branch v1 -> v2: - Introduce new gfn_to_pfn_page functions instead of modifying the behavior of existing gfn_to_pfn functions, to make the change less invasive. - Drop changes to mmu_audit.c - Include Nicholas Piggin's patch to avoid corrupting refcount in the follow_pte case, and use it in depreciated gfn_to_pfn functions. - Rebase on kvm/next David Stevens (7): KVM: mmu: Introduce __kvm_follow_pfn function KVM: mmu: Make __kvm_follow_pfn not imply FOLL_GET KVM: x86/mmu: Migrate to __kvm_follow_pfn KVM: x86/mmu: Don't pass FOLL_GET to __kvm_follow_pfn KVM: arm64: Migrate to __kvm_follow_pfn KVM: PPC: Migrate to __kvm_follow_pfn KVM: mmu: remove __gfn_to_pfn_memslot Sean Christopherson (1): KVM: Assert that a page's refcount is elevated when marking accessed/dirty arch/arm64/kvm/mmu.c | 25 +-- arch/powerpc/include/asm/kvm_book3s.h | 2 +- arch/powerpc/kvm/book3s_64_mmu_hv.c | 38 ++-- arch/powerpc/kvm/book3s_64_mmu_radix.c | 50 +++--- arch/powerpc/kvm/book3s_hv_nested.c | 4 +- arch/x86/kvm/mmu/mmu.c | 94 +++++++--- arch/x86/kvm/mmu/mmu_internal.h | 1 + arch/x86/kvm/mmu/paging_tmpl.h | 8 +- arch/x86/kvm/mmu/spte.c | 4 +- arch/x86/kvm/mmu/spte.h | 12 +- arch/x86/kvm/mmu/tdp_mmu.c | 22 ++- include/linux/kvm_host.h | 26 +++ virt/kvm/kvm_main.c | 231 ++++++++++++++----------- virt/kvm/kvm_mm.h | 3 +- virt/kvm/pfncache.c | 10 +- 15 files changed, 316 insertions(+), 214 deletions(-) -- 2.42.0.rc1.204.g551eb34607-goog