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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44642C33CAA for ; Wed, 8 Jan 2020 20:27:14 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 071F020705 for ; Wed, 8 Jan 2020 20:27:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 071F020705 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id A4B084B183; Wed, 8 Jan 2020 15:27:13 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SqksLITJMwSG; Wed, 8 Jan 2020 15:27:12 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 4262F4B13B; Wed, 8 Jan 2020 15:27:09 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 4A6174B13F for ; Wed, 8 Jan 2020 15:27:08 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id AhJ0cWHn1mlK for ; Wed, 8 Jan 2020 15:27:07 -0500 (EST) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 1E6E84B12F for ; Wed, 8 Jan 2020 15:27:06 -0500 (EST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jan 2020 12:27:06 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,411,1571727600"; d="scan'208";a="211658366" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga007.jf.intel.com with ESMTP; 08 Jan 2020 12:27:06 -0800 From: Sean Christopherson To: Paolo Bonzini Subject: [PATCH 04/14] KVM: Play nice with read-only memslots when querying host page size Date: Wed, 8 Jan 2020 12:24:38 -0800 Message-Id: <20200108202448.9669-5-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200108202448.9669-1-sean.j.christopherson@intel.com> References: <20200108202448.9669-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Cc: Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , Peter Zijlstra , Dave Hansen , Paul Mackerras , linux-mm@kvack.org, kvmarm@lists.cs.columbia.edu, Dave Jiang , linux-nvdimm , Marc Zyngier , Joerg Roedel , syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com, Barret Rhoden , kvm-ppc@vger.kernel.org, Liran Alon , Andy Lutomirski , Dan Williams , Andrew Morton , linux-arm-kernel@lists.infradead.org, Jim Mattson , linux-kernel@vger.kernel.org, Sean Christopherson , Jason Zeng , Vitaly Kuznetsov X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Open code an equivalent of kvm_vcpu_gfn_to_memslot() when querying the host page size to avoid the "writable" check in __gfn_to_hva_many(), which will always fail on read-only memslots due to gfn_to_hva() assuming writes. Functionally, this allows x86 to create large mappings for read-only memslots that are backed by HugeTLB mappings. Note, the changelog for commit 05da45583de9 ("KVM: MMU: large page support") states "If the largepage contains write-protected pages, a large pte is not used.", but "write-protected" refers to pages that are temporarily read-only, e.g. read-only memslots didn't even exist at the time. Fixes: 4d8b81abc47b ("KVM: introduce readonly memslot") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson --- virt/kvm/kvm_main.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5f7f06824c2b..d9aced677ddd 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1418,15 +1418,23 @@ EXPORT_SYMBOL_GPL(kvm_is_visible_gfn); unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn) { + struct kvm_memory_slot *slot; struct vm_area_struct *vma; unsigned long addr, size; size = PAGE_SIZE; - addr = kvm_vcpu_gfn_to_hva(vcpu, gfn); - if (kvm_is_error_hva(addr)) + /* + * Manually do the equivalent of kvm_vcpu_gfn_to_hva() to avoid the + * "writable" check in __gfn_to_hva_many(), which will always fail on + * read-only memslots due to gfn_to_hva() assuming writes. + */ + slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + if (!slot || slot->flags & KVM_MEMSLOT_INVALID) return PAGE_SIZE; + addr = __gfn_to_hva_memslot(slot, gfn); + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, addr); if (!vma) -- 2.24.1 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm