From patchwork Tue Feb 18 21:07:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11389687 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 E4BB9109A for ; Tue, 18 Feb 2020 21:11:14 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C00FC2176D for ; Tue, 18 Feb 2020 21:11:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="A7A6LwXT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C00FC2176D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=TIGvT1Q5koU5D7TwbXm3KnYp22aXW6PHoI4mDLFETuk=; b=A7A6LwXTMOQFWf iXXtOe+Ipn5hR1sQbD2SofZVzulTgT1JdupH/A1kqIsII+TFpnGLBBZbcZ1hd8WrgUkrUZkr1Nx1U lXKZiZqn8KhSN8R1c0akJs9cLmSb569ggZt2KHJJb6f6poUI15o/4ipQybNbx+I2Bj2+qzUX6MJgn soRrKFewTegXXMKsdxC0fypApMqhKUCEUu5xkTa+Q+hh7xGY8Ufflu8nrHbkIvTHeBrNpwraeJVyf hRMsb/KjHetDs//htojdSYunnDWK10wmafadOEyk+1ESyKeKBDTGimRYj1BScFZbeBneBWayIB9Ol KaViNZegR6lCCk+P7nPw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4A96-0005WG-RU; Tue, 18 Feb 2020 21:11:08 +0000 Received: from mga14.intel.com ([192.55.52.115]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4A5t-00011U-KA for linux-arm-kernel@lists.infradead.org; Tue, 18 Feb 2020 21:07:54 +0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Feb 2020 13:07:46 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,457,1574150400"; d="scan'208";a="253856451" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.202]) by orsmga002.jf.intel.com with ESMTP; 18 Feb 2020 13:07:46 -0800 From: Sean Christopherson To: Paolo Bonzini Subject: [PATCH v6 16/22] KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() Date: Tue, 18 Feb 2020 13:07:30 -0800 Message-Id: <20200218210736.16432-17-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200218210736.16432-1-sean.j.christopherson@intel.com> References: <20200218210736.16432-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200218_130749_725423_480F3242 X-CRM114-Status: GOOD ( 20.75 ) X-Spam-Score: -5.0 (-----) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-5.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [192.55.52.115 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , Peter Xu , linux-mips@vger.kernel.org, Paul Mackerras , kvmarm@lists.cs.columbia.edu, Janosch Frank , Marc Zyngier , Joerg Roedel , Christian Borntraeger , Julien Thierry , Suzuki K Poulose , kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jim Mattson , Cornelia Huck , Christoffer Dall , Sean Christopherson , linux-kernel@vger.kernel.org, James Morse , Vitaly Kuznetsov , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?q?=C3=A9?= Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Rework kvm_get_dirty_log() so that it "returns" the associated memslot on success. A future patch will rework memslot handling such that id_to_memslot() can return NULL, returning the memslot makes it more obvious that the validity of the memslot has been verified, i.e. precludes the need to add validity checks in the arch code that are technically unnecessary. To maintain ordering in s390, move the call to kvm_arch_sync_dirty_log() from s390's kvm_vm_ioctl_get_dirty_log() to the new kvm_get_dirty_log(). This is a nop for PPC, the only other arch that doesn't select KVM_GENERIC_DIRTYLOG_READ_PROTECT, as its sync_dirty_log() is empty. Ideally, moving the sync_dirty_log() call would be done in a separate patch, but it can't be done in a follow-on patch because that would temporarily break s390's ordering. Making the move in a preparatory patch would be functionally correct, but would create an odd scenario where the moved sync_dirty_log() would operate on a "different" memslot due to consuming the result of a different id_to_memslot(). The memslot couldn't actually be different as slots_lock is held, but the code is confusing enough as it is, i.e. moving sync_dirty_log() in this patch is the lesser of all evils. Signed-off-by: Sean Christopherson --- arch/powerpc/kvm/book3s_pr.c | 6 +----- arch/s390/kvm/kvm-s390.c | 12 ++---------- include/linux/kvm_host.h | 2 +- virt/kvm/kvm_main.c | 27 +++++++++++++++++++-------- 4 files changed, 23 insertions(+), 24 deletions(-) diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 71ae332b91c9..3bc2f5da8fa1 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1884,7 +1884,6 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) static int kvm_vm_ioctl_get_dirty_log_pr(struct kvm *kvm, struct kvm_dirty_log *log) { - struct kvm_memslots *slots; struct kvm_memory_slot *memslot; struct kvm_vcpu *vcpu; ulong ga, ga_end; @@ -1894,15 +1893,12 @@ static int kvm_vm_ioctl_get_dirty_log_pr(struct kvm *kvm, mutex_lock(&kvm->slots_lock); - r = kvm_get_dirty_log(kvm, log, &is_dirty); + r = kvm_get_dirty_log(kvm, log, &is_dirty, &memslot); if (r) goto out; /* If nothing is dirty, don't bother messing with page tables. */ if (is_dirty) { - slots = kvm_memslots(kvm); - memslot = id_to_memslot(slots, log->slot); - ga = memslot->base_gfn << PAGE_SHIFT; ga_end = ga + (memslot->npages << PAGE_SHIFT); diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 2adbc2fde382..fb081c5715b2 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -611,9 +611,8 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, { int r; unsigned long n; - struct kvm_memslots *slots; struct kvm_memory_slot *memslot; - int is_dirty = 0; + int is_dirty; if (kvm_is_ucontrol(kvm)) return -EINVAL; @@ -624,14 +623,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, if (log->slot >= KVM_USER_MEM_SLOTS) goto out; - slots = kvm_memslots(kvm); - memslot = id_to_memslot(slots, log->slot); - r = -ENOENT; - if (!memslot->dirty_bitmap) - goto out; - - kvm_arch_sync_dirty_log(kvm, memslot); - r = kvm_get_dirty_log(kvm, log, &is_dirty); + r = kvm_get_dirty_log(kvm, log, &is_dirty, &memslot); if (r) goto out; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4588b988ebf1..f1501a08e7ac 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -828,7 +828,7 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm, #else /* !CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log); int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, - int *is_dirty); + int *is_dirty, struct kvm_memory_slot **memslot); #endif int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d986168ee8b1..182b36115ba0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1202,31 +1202,42 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm, } #ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT -int kvm_get_dirty_log(struct kvm *kvm, - struct kvm_dirty_log *log, int *is_dirty) +/** + * kvm_get_dirty_log - get a snapshot of dirty pages + * @kvm: pointer to kvm instance + * @log: slot id and address to which we copy the log + * @is_dirty: set to '1' if any dirty pages were found + * @memslot: set to the associated memslot, always valid on success + */ +int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, + int *is_dirty, struct kvm_memory_slot **memslot) { struct kvm_memslots *slots; - struct kvm_memory_slot *memslot; int i, as_id, id; unsigned long n; unsigned long any = 0; + *memslot = NULL; + *is_dirty = 0; + as_id = log->slot >> 16; id = (u16)log->slot; if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) return -EINVAL; slots = __kvm_memslots(kvm, as_id); - memslot = id_to_memslot(slots, id); - if (!memslot->dirty_bitmap) + *memslot = id_to_memslot(slots, id); + if (!(*memslot)->dirty_bitmap) return -ENOENT; - n = kvm_dirty_bitmap_bytes(memslot); + kvm_arch_sync_dirty_log(kvm, *memslot); + + n = kvm_dirty_bitmap_bytes(*memslot); for (i = 0; !any && i < n/sizeof(long); ++i) - any = memslot->dirty_bitmap[i]; + any = (*memslot)->dirty_bitmap[i]; - if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n)) + if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n)) return -EFAULT; if (any)