From patchwork Sat Oct 14 02:42:51 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Mackerras X-Patchwork-Id: 825791 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=ozlabs.org header.i=@ozlabs.org header.b="hxGdOuum"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3yDTQp3Zq4z9sNr for ; Sat, 14 Oct 2017 13:42:58 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753356AbdJNCm5 (ORCPT ); Fri, 13 Oct 2017 22:42:57 -0400 Received: from ozlabs.org ([103.22.144.67]:36945 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751572AbdJNCm4 (ORCPT ); Fri, 13 Oct 2017 22:42:56 -0400 Received: by ozlabs.org (Postfix, from userid 1003) id 3yDTQk54Bkz9sNr; Sat, 14 Oct 2017 13:42:54 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ozlabs.org; s=201707; t=1507948974; bh=xkr4FJmIwGcRZwyVsWRO67SwyVGXEHhKtJbAGX55sYM=; h=Date:From:To:Subject:From; b=hxGdOuumK84Xpv+y7cIha46wOcVIYN9eP03rFqXRu2XtdUfC+wYx7sBkAHdXEoilS RWFvGKe/5hKAPqov7t9kwCn9GtJvT7sgtUXO1S8k8ArH/Prjn1HNqcPXzHK8cB6Uo7 pvodEOUgrMqDeGOiSu4XXpABVyGjF5jjgIikl/sE9xKrorsL/CVvKOe622pG2iMKCM 0QphyHQMoc9VaGFWXtcljqZtVvaWUuA/8PWDgnl1MKLnWuNRmdh4hp5fXXxSopy1U1 yxjC161YViup3hliyotww4I+5QDkT85Zq2DpyJjhUEIu9gXOSTphAquBna5a1hpx0g ZrVtPht/WLbaA== Date: Sat, 14 Oct 2017 13:42:51 +1100 From: Paul Mackerras To: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org Subject: [PATCH] KVM: PPC: Book3S HV: Explicitly disable HPT operations on radix guests Message-ID: <20171014024251.GF26120@fergus.ozlabs.ibm.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org This adds code to make sure that we don't try to access the non-existent HPT for a radix guest using the htab file for the VM in debugfs, a file descriptor obtained using the KVM_PPC_GET_HTAB_FD ioctl, or via the KVM_PPC_RESIZE_HPT_{PREPARE,COMMIT} ioctls. At present nothing bad happens if userspace does access these interfaces on a radix guest, mostly because kvmppc_hpt_npte() gives 0 for a radix guest, which in turn is because 1 << -4 comes out as 0 on POWER processors. However, that relies on undefined behaviour, so it is better to be explicit about not accessing the HPT for a radix guest. Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 7df89d5..624b011 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -1454,7 +1454,7 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm, struct kvm_resize_hpt *resize; int ret; - if (flags != 0) + if (flags != 0 || kvm_is_radix(kvm)) return -EINVAL; if (shift && ((shift < 18) || (shift > 46))) @@ -1520,7 +1520,7 @@ long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm, struct kvm_resize_hpt *resize; long ret; - if (flags != 0) + if (flags != 0 || kvm_is_radix(kvm)) return -EINVAL; if (shift && ((shift < 18) || (shift > 46))) @@ -1706,6 +1706,8 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf, if (!access_ok(VERIFY_WRITE, buf, count)) return -EFAULT; + if (kvm_is_radix(kvm)) + return 0; first_pass = ctx->first_pass; flags = ctx->flags; @@ -1803,6 +1805,8 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf, if (!access_ok(VERIFY_READ, buf, count)) return -EFAULT; + if (kvm_is_radix(kvm)) + return -EINVAL; /* lock out vcpus from running while we're doing this */ mutex_lock(&kvm->lock); @@ -2001,6 +2005,10 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf, struct kvm *kvm; __be64 *hptp; + kvm = p->kvm; + if (kvm_is_radix(kvm)) + return 0; + ret = mutex_lock_interruptible(&p->mutex); if (ret) return ret; @@ -2023,7 +2031,6 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf, } } - kvm = p->kvm; i = p->hpt_index; hptp = (__be64 *)(kvm->arch.hpt.virt + (i * HPTE_SIZE)); for (; len != 0 && i < kvmppc_hpt_npte(&kvm->arch.hpt);