From patchwork Tue Oct 20 06:18:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A . Shutemov" X-Patchwork-Id: 11845765 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0CA9C16C0 for ; Tue, 20 Oct 2020 06:19:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A12C722409 for ; Tue, 20 Oct 2020 06:19:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="kWnjG/bx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A12C722409 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shutemov.name Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B21CC6B0074; Tue, 20 Oct 2020 02:19:12 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id AF9376B0075; Tue, 20 Oct 2020 02:19:12 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 995A46B0078; Tue, 20 Oct 2020 02:19:12 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 5F4CE6B0074 for ; Tue, 20 Oct 2020 02:19:12 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 100F982DF882 for ; Tue, 20 Oct 2020 06:19:12 +0000 (UTC) X-FDA: 77391301344.23.beam29_28087562723d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id E5EC237604 for ; Tue, 20 Oct 2020 06:19:11 +0000 (UTC) X-Spam-Summary: 1,0,0,bfe7ae6683d6af72,d41d8cd98f00b204,kirill@shutemov.name,,RULES_HIT:1:2:41:355:379:541:960:973:988:989:1260:1311:1314:1345:1359:1437:1515:1605:1730:1747:1777:1792:2194:2199:2393:2553:2559:2562:2736:2901:3138:3139:3140:3141:3142:3865:3866:3867:3868:3870:3871:3872:3874:4051:4250:4321:4605:5007:6119:6261:6653:6742:7903:7904:10004:10226:11026:11473:11658:11914:12043:12048:12296:12297:12438:12517:12519:12555:12895:12986:13161:13229:13894:14096:21080:21444:21451:21627:21740:21987:21990:30003:30012:30054:30069:30079:30090,0,RBL:209.85.208.194:@shutemov.name:.lbl8.mailshell.net-62.8.84.100 66.201.201.201;04yf79ajn9gkesn9ksnre3rumz1ikycj1xkckjyb4fw4kzfg5euqkk5cmafd9rk.d9hwqtw7rh1cfsb1gm4kogrx4ecuc63k3rmxdyp1pg4aj34sgq1rwhgm5hknppr.r-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: beam29_28087562723d X-Filterd-Recvd-Size: 12101 Received: from mail-lj1-f194.google.com (mail-lj1-f194.google.com [209.85.208.194]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Tue, 20 Oct 2020 06:19:11 +0000 (UTC) Received: by mail-lj1-f194.google.com with SMTP id c21so766887ljj.0 for ; Mon, 19 Oct 2020 23:19:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Ef3vnZp/GnAIOhUojdZDqsMeSzQG+k/o8v/cqaX5tdE=; b=kWnjG/bxvvaKB7p7Og+d8rHcQSxNwWjP6TC59FneVw8z/VNXgUaDMKTQO/MkwPrA+x +duFDtLhAFDA0qpugJYlrviajPw8NRXeR/ysVV+ZxXdgzP+uvH9BsVizNcK20WoevkeV WMSbCL4u7ayNAPEVdnIplFR8AGo2eUH7Qa6s/QpmNARyn2T7XGVKz4Q2RsWWEnVchVQB 9D4kOaDUpfEcu8nwrB5TUSRXAtenzPz54EqxIf0OKr5R1UAEtOjz5vAv6gktjIWRMcB8 Tz0Uq4xh7vFJJnA9Pr4i4yyNJxAvwhYezd7vtQicoEwlgj5ko/lCtadFljYF5rIySZRl XyAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ef3vnZp/GnAIOhUojdZDqsMeSzQG+k/o8v/cqaX5tdE=; b=Xosqshyq/dYm8JejXKK4MvGlwRNnqBqpD0BPYfhufpJsmOKx+1qflWCVMEu4jfW/Yx cP7NG9y/MO1HKHQV3yWV3WD/yrX9lje5llDOj808m6y6aRlck9EZc+l70aN61Cq7Yuqy FeLWj5TMVT7VaYAn1yNvRDIYWMdEhGw3b0S86A/qoSYKuhu+GPZmAFTeo825aMsreHIF nHF9JpOTI9sm3k6k5wdF43JF5P9S6cJfQ646dma75Am1BAuW+kSMsMfZmqONqdGmeAaw W1pt1eLWK41Q3rXTbquRTVYSH+Lw8ms9B0+3XwadD1uE1sbx2Nc7OW54NK2KUZTPFEO9 4uUA== X-Gm-Message-State: AOAM533z7sZ9aiw3ugdl/dJbj6WyZysUSkOU490OrxCihrYzFA470Q7K uw0lQA/KAq02OckDI/TxLnZrUw== X-Google-Smtp-Source: ABdhPJyvDjiTcYo3ooj2XDbkY21HO+vY/E6/whgeBJA4ZvSFIs8MEUig63kvuD9QS067pDfLSnnJGA== X-Received: by 2002:a2e:9bce:: with SMTP id w14mr478315ljj.439.1603174750219; Mon, 19 Oct 2020 23:19:10 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id h11sm194817ljc.21.2020.10.19.23.19.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Oct 2020 23:19:09 -0700 (PDT) From: "Kirill A. Shutemov" X-Google-Original-From: "Kirill A. Shutemov" Received: by box.localdomain (Postfix, from userid 1000) id 03C94102F68; Tue, 20 Oct 2020 09:19:02 +0300 (+03) To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel Cc: David Rientjes , Andrea Arcangeli , Kees Cook , Will Drewry , "Edgecombe, Rick P" , "Kleen, Andi" , Liran Alon , Mike Rapoport , x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [RFCv2 09/16] KVM: mm: Introduce VM_KVM_PROTECTED Date: Tue, 20 Oct 2020 09:18:52 +0300 Message-Id: <20201020061859.18385-10-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201020061859.18385-1-kirill.shutemov@linux.intel.com> References: <20201020061859.18385-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 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: The new VMA flag that indicate a VMA that is not accessible to userspace but usable by kernel with GUP if FOLL_KVM is specified. The FOLL_KVM is only used in the KVM code. The code has to know how to deal with such pages. Signed-off-by: Kirill A. Shutemov --- include/linux/mm.h | 8 ++++++++ mm/gup.c | 20 ++++++++++++++++---- mm/huge_memory.c | 20 ++++++++++++++++---- mm/memory.c | 3 +++ mm/mmap.c | 3 +++ virt/kvm/async_pf.c | 2 +- virt/kvm/kvm_main.c | 9 +++++---- 7 files changed, 52 insertions(+), 13 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 16b799a0522c..c8d8cdcbc425 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -342,6 +342,8 @@ extern unsigned int kobjsize(const void *objp); # define VM_MAPPED_COPY VM_ARCH_1 /* T if mapped copy of data (nommu mmap) */ #endif +#define VM_KVM_PROTECTED 0 + #ifndef VM_GROWSUP # define VM_GROWSUP VM_NONE #endif @@ -658,6 +660,11 @@ static inline bool vma_is_accessible(struct vm_area_struct *vma) return vma->vm_flags & VM_ACCESS_FLAGS; } +static inline bool vma_is_kvm_protected(struct vm_area_struct *vma) +{ + return vma->vm_flags & VM_KVM_PROTECTED; +} + #ifdef CONFIG_SHMEM /* * The vma_is_shmem is not inline because it is used only by slow @@ -2766,6 +2773,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_SPLIT_PMD 0x20000 /* split huge pmd before returning */ #define FOLL_PIN 0x40000 /* pages must be released via unpin_user_page */ #define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ +#define FOLL_KVM 0x100000 /* access to VM_KVM_PROTECTED VMAs */ /* * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each diff --git a/mm/gup.c b/mm/gup.c index e869c634cc9a..accf6db0c06f 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -384,10 +384,19 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address, * FOLL_FORCE can write to even unwritable pte's, but only * after we've gone through a COW cycle and they are dirty. */ -static inline bool can_follow_write_pte(pte_t pte, unsigned int flags) +static inline bool can_follow_write_pte(struct vm_area_struct *vma, + pte_t pte, unsigned int flags) { - return pte_write(pte) || - ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)); + if (pte_write(pte)) + return true; + + if ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)) + return true; + + if (!vma_is_kvm_protected(vma) || !(vma->vm_flags & VM_WRITE)) + return false; + + return (vma->vm_flags & VM_SHARED) || page_mapcount(pte_page(pte)) == 1; } static struct page *follow_page_pte(struct vm_area_struct *vma, @@ -430,7 +439,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, } if ((flags & FOLL_NUMA) && pte_protnone(pte)) goto no_page; - if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) { + if ((flags & FOLL_WRITE) && !can_follow_write_pte(vma, pte, flags)) { pte_unmap_unlock(ptep, ptl); return NULL; } @@ -750,6 +759,9 @@ static struct page *follow_page_mask(struct vm_area_struct *vma, ctx->page_mask = 0; + if (vma_is_kvm_protected(vma) && (flags & FOLL_KVM)) + flags &= ~FOLL_NUMA; + /* make this handle hugepd */ page = follow_huge_addr(mm, address, flags & FOLL_WRITE); if (!IS_ERR(page)) { diff --git a/mm/huge_memory.c b/mm/huge_memory.c index da397779a6d4..ec8cf9a40cfd 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1322,10 +1322,19 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) * FOLL_FORCE can write to even unwritable pmd's, but only * after we've gone through a COW cycle and they are dirty. */ -static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) +static inline bool can_follow_write_pmd(struct vm_area_struct *vma, + pmd_t pmd, unsigned int flags) { - return pmd_write(pmd) || - ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); + if (pmd_write(pmd)) + return true; + + if ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)) + return true; + + if (!vma_is_kvm_protected(vma) || !(vma->vm_flags & VM_WRITE)) + return false; + + return (vma->vm_flags & VM_SHARED) || page_mapcount(pmd_page(pmd)) == 1; } struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, @@ -1338,7 +1347,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, assert_spin_locked(pmd_lockptr(mm, pmd)); - if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) + if (flags & FOLL_WRITE && !can_follow_write_pmd(vma, *pmd, flags)) goto out; /* Avoid dumping huge zero page */ @@ -1412,6 +1421,9 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd) bool was_writable; int flags = 0; + if (vma_is_kvm_protected(vma)) + return VM_FAULT_SIGBUS; + vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); if (unlikely(!pmd_same(pmd, *vmf->pmd))) goto out_unlock; diff --git a/mm/memory.c b/mm/memory.c index eeae590e526a..2c9756b4e52f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4165,6 +4165,9 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) bool was_writable = pte_savedwrite(vmf->orig_pte); int flags = 0; + if (vma_is_kvm_protected(vma)) + return VM_FAULT_SIGBUS; + /* * The "pte" at this point cannot be used safely without * validation through pte_unmap_same(). It's of NUMA type but diff --git a/mm/mmap.c b/mm/mmap.c index bdd19f5b994e..be699f688b6c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -112,6 +112,9 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags) (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | pgprot_val(arch_vm_get_page_prot(vm_flags))); + if (vm_flags & VM_KVM_PROTECTED) + ret = PAGE_NONE; + return arch_filter_pgprot(ret); } EXPORT_SYMBOL(vm_get_page_prot); diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index dd777688d14a..85a2f99f6e9b 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -61,7 +61,7 @@ static void async_pf_execute(struct work_struct *work) * access remotely. */ mmap_read_lock(mm); - get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, NULL, + get_user_pages_remote(mm, addr, 1, FOLL_WRITE | FOLL_KVM, NULL, NULL, &locked); if (locked) mmap_read_unlock(mm); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index a9884cb8c867..125db5a73e10 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1794,7 +1794,7 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w static inline int check_user_page_hwpoison(unsigned long addr) { - int rc, flags = FOLL_HWPOISON | FOLL_WRITE; + int rc, flags = FOLL_HWPOISON | FOLL_WRITE | FOLL_KVM; rc = get_user_pages(addr, 1, flags, NULL, NULL); return rc == -EHWPOISON; @@ -1836,7 +1836,7 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault, static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault, bool *writable, kvm_pfn_t *pfn) { - unsigned int flags = FOLL_HWPOISON; + unsigned int flags = FOLL_HWPOISON | FOLL_KVM; struct page *page; int npages = 0; @@ -2327,7 +2327,7 @@ int copy_from_guest(void *data, unsigned long hva, int len, bool protected) check_object_size(data, len, false); while ((seg = next_segment(len, offset)) != 0) { - npages = get_user_pages_unlocked(hva, 1, &page, 0); + npages = get_user_pages_unlocked(hva, 1, &page, FOLL_KVM); if (npages != 1) return -EFAULT; memcpy(data, page_address(page) + offset, seg); @@ -2354,7 +2354,8 @@ int copy_to_guest(unsigned long hva, const void *data, int len, bool protected) check_object_size(data, len, true); while ((seg = next_segment(len, offset)) != 0) { - npages = get_user_pages_unlocked(hva, 1, &page, FOLL_WRITE); + npages = get_user_pages_unlocked(hva, 1, &page, + FOLL_WRITE | FOLL_KVM); if (npages != 1) return -EFAULT; memcpy(page_address(page) + offset, data, seg);