From patchwork Fri Nov 30 08:09:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Yi" X-Patchwork-Id: 10705929 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4F4A214BD for ; Fri, 30 Nov 2018 08:09:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 422BF2F891 for ; Fri, 30 Nov 2018 08:09:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 367A52F895; Fri, 30 Nov 2018 08:09:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C1A012F891 for ; Fri, 30 Nov 2018 08:09:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727368AbeK3TRx (ORCPT ); Fri, 30 Nov 2018 14:17:53 -0500 Received: from mga01.intel.com ([192.55.52.88]:17444 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727347AbeK3TRw (ORCPT ); Fri, 30 Nov 2018 14:17:52 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Nov 2018 00:09:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,297,1539673200"; d="scan'208";a="105480402" Received: from linux.intel.com ([10.54.29.200]) by orsmga003.jf.intel.com with ESMTP; 30 Nov 2018 00:09:24 -0800 Received: from dazhang1-ssd.sh.intel.com (unknown [10.239.48.128]) by linux.intel.com (Postfix) with ESMTP id B8D36580213; Fri, 30 Nov 2018 00:09:22 -0800 (PST) From: Zhang Yi To: pbonzini@redhat.com, mdontu@bitdefender.com, ncitu@bitdefender.com Cc: rkrcmar@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Zhang Yi Subject: [RFC PATCH V2 09/11] KVM: VMX: Update the EPT leaf entry indicated with the SPP enable bit. Date: Fri, 30 Nov 2018 16:09:07 +0800 Message-Id: <09004f3e9fbe0a74223bf23f1bbe980398fa854b.1543481993.git.yi.z.zhang@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If the sub-page write permission VM-execution control is set, treatment of write accesses to guest-physical accesses depends on the state of the accumulated write-access bit (position 1) and sub-page permission bit (position 61) in the EPT leaf paging-structure. Software will update the EPT leaf entry sub-page permission bit while kvm_set_subpage. If the EPT write-access bit set to 0 and the SPP bit set to 1 in the leaf EPT paging-structure entry that maps a 4KB page, then the hardware will look up a VMM-managed Sub-Page Permission Table (SPPT), which will also be prepared by setup kvm_set_subpage. Signed-off-by: Zhang Yi --- arch/x86/kvm/mmu.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b1773c6..d512125 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1668,6 +1668,87 @@ int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu) return 0; } +static bool __rmap_open_subpage_bit(struct kvm *kvm, + struct kvm_rmap_head *rmap_head) +{ + struct rmap_iterator iter; + bool flush = false; + u64 *sptep; + u64 spte; + + for_each_rmap_spte(rmap_head, &iter, sptep) { + /* + * SPP works only when the page is unwritable + * and SPP bit is set + */ + flush |= spte_write_protect(sptep, false); + spte = *sptep | PT_SPP_MASK; + flush |= mmu_spte_update(sptep, spte); + } + + return flush; +} + +static int kvm_mmu_open_subpage_write_protect(struct kvm *kvm, + struct kvm_memory_slot *slot, + gfn_t gfn) +{ + struct kvm_rmap_head *rmap_head; + bool flush = false; + + /* + * we only support spp in a normal 4K level 1 page frame + * If it a huge page, we drop it. + */ + rmap_head = __gfn_to_rmap(gfn, PT_PAGE_TABLE_LEVEL, slot); + + if (!rmap_head->val) + return -EFAULT; + + flush |= __rmap_open_subpage_bit(kvm, rmap_head); + + if (flush) + kvm_flush_remote_tlbs(kvm); + + return 0; +} + +static bool __rmap_clear_subpage_bit(struct kvm *kvm, + struct kvm_rmap_head *rmap_head) +{ + struct rmap_iterator iter; + bool flush = false; + u64 *sptep; + u64 spte; + + for_each_rmap_spte(rmap_head, &iter, sptep) { + spte = (*sptep & ~PT_SPP_MASK) | PT_WRITABLE_MASK; + flush |= mmu_spte_update(sptep, spte); + } + + return flush; +} + +static int kvm_mmu_clear_subpage_write_protect(struct kvm *kvm, + struct kvm_memory_slot *slot, + gfn_t gfn) +{ + struct kvm_rmap_head *rmap_head; + bool flush = false; + + rmap_head = __gfn_to_rmap(gfn, PT_PAGE_TABLE_LEVEL, slot); + + if (!rmap_head->val) + return -EFAULT; + + flush |= __rmap_clear_subpage_bit(kvm, rmap_head); + + if (flush) + kvm_flush_remote_tlbs(kvm); + + return 0; +} + bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm, struct kvm_memory_slot *slot, u64 gfn) { @@ -4175,12 +4256,31 @@ int kvm_mmu_set_subpages(struct kvm *kvm, struct kvm_subpage *spp_info) int npages = spp_info->npages; struct kvm_memory_slot *slot; u32 *wp_map; + int ret; int i; for (i = 0; i < npages; i++, gfn++) { slot = gfn_to_memslot(kvm, gfn); if (!slot) return -EFAULT; + + /* + * open SPP bit in EPT leaf entry to write protect the + * sub-pages in corresponding page + */ + if (access != (u32)((1ULL << 32) - 1)) + ret = kvm_mmu_open_subpage_write_protect(kvm, + slot, gfn); + else + ret = kvm_mmu_clear_subpage_write_protect(kvm, + slot, gfn); + + if (ret) { + pr_info("SPP ,didn't get the gfn:%llx from EPT leaf level1\n" + "Current we didn't support huge page on SPP\n" + "Please try to disable the huge page\n", gfn); + return -EFAULT; + } wp_map = gfn_to_subpage_wp_info(slot, gfn); *wp_map = access; }