From patchwork Wed Aug 7 10:03:46 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bharat Bhushan X-Patchwork-Id: 265460 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CA10A2C022C for ; Wed, 7 Aug 2013 20:08:11 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932375Ab3HGKIL (ORCPT ); Wed, 7 Aug 2013 06:08:11 -0400 Received: from tx2ehsobe002.messaging.microsoft.com ([65.55.88.12]:14675 "EHLO tx2outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932419Ab3HGKII (ORCPT ); Wed, 7 Aug 2013 06:08:08 -0400 Received: from mail149-tx2-R.bigfish.com (10.9.14.253) by TX2EHSOBE002.bigfish.com (10.9.40.22) with Microsoft SMTP Server id 14.1.225.22; Wed, 7 Aug 2013 10:08:07 +0000 Received: from mail149-tx2 (localhost [127.0.0.1]) by mail149-tx2-R.bigfish.com (Postfix) with ESMTP id D265D20116; Wed, 7 Aug 2013 10:08:07 +0000 (UTC) X-Forefront-Antispam-Report: CIP:70.37.183.190; KIP:(null); UIP:(null); IPV:NLI; H:mail.freescale.net; RD:none; EFVD:NLI X-SpamScore: 6 X-BigFish: VS6(zz853kzz1f42h208ch1ee6h1de0h1fdah2073h1202h1e76h1d1ah1d2ah1fc6h1082kzz1de098h8275bh1de097hz2dh2a8h668h839he5bhf0ah107ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e1dh1e23h1155h) Received: from mail149-tx2 (localhost.localdomain [127.0.0.1]) by mail149-tx2 (MessageSwitch) id 1375870085931804_32658; Wed, 7 Aug 2013 10:08:05 +0000 (UTC) Received: from TX2EHSMHS018.bigfish.com (unknown [10.9.14.242]) by mail149-tx2.bigfish.com (Postfix) with ESMTP id CDE9324004F; Wed, 7 Aug 2013 10:08:05 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by TX2EHSMHS018.bigfish.com (10.9.99.118) with Microsoft SMTP Server (TLS) id 14.16.227.3; Wed, 7 Aug 2013 10:08:05 +0000 Received: from tx30smr01.am.freescale.net (10.81.153.31) by 039-SN1MMR1-004.039d.mgd.msft.net (10.84.1.14) with Microsoft SMTP Server (TLS) id 14.3.136.1; Wed, 7 Aug 2013 10:08:05 +0000 Received: from freescale.com ([10.232.15.72]) by tx30smr01.am.freescale.net (8.14.3/8.14.0) with SMTP id r77A80rH030846; Wed, 7 Aug 2013 03:08:01 -0700 Received: by freescale.com (sSMTP sendmail emulation); Wed, 07 Aug 2013 15:34:04 +0530 From: Bharat Bhushan To: , , , , CC: Bharat Bhushan , Bharat Bhushan Subject: [PATCH 2/2] kvm: ppc: booke: check range page invalidation progress on page setup Date: Wed, 7 Aug 2013 15:33:46 +0530 Message-ID: <1375869826-17509-3-git-send-email-Bharat.Bhushan@freescale.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1375869826-17509-1-git-send-email-Bharat.Bhushan@freescale.com> References: <1375869826-17509-1-git-send-email-Bharat.Bhushan@freescale.com> MIME-Version: 1.0 X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org When the MM code is invalidating a range of pages, it calls the KVM kvm_mmu_notifier_invalidate_range_start() notifier function, which calls kvm_unmap_hva_range(), which arranges to flush all the TLBs for guest pages. However, the Linux PTEs for the range being flushed are still valid at that point. We are not supposed to establish any new references to pages in the range until the ...range_end() notifier gets called. The PPC-specific KVM code doesn't get any explicit notification of that; instead, we are supposed to use mmu_notifier_retry() to test whether we are or have been inside a range flush notifier pair while we have been referencing a page. This patch calls the mmu_notifier_retry() while mapping the guest page to ensure we are not referencing a page when in range invalidation. This call is inside a region locked with kvm->mmu_lock, which is the same lock that is called by the KVM MMU notifier functions, thus ensuring that no new notification can proceed while we are in the locked region. Signed-off-by: Bharat Bhushan Acked-by: Scott Wood since it's currently the Acked-by: Alexander Graf --- arch/powerpc/kvm/e500_mmu_host.c | 19 +++++++++++++++++-- 1 files changed, 17 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c index ff6dd66..ae4eaf6 100644 --- a/arch/powerpc/kvm/e500_mmu_host.c +++ b/arch/powerpc/kvm/e500_mmu_host.c @@ -329,8 +329,14 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500, int tsize = BOOK3E_PAGESZ_4K; unsigned long tsize_pages = 0; pte_t *ptep; - int wimg = 0; + int wimg = 0, ret = 0; pgd_t *pgdir; + unsigned long mmu_seq; + struct kvm *kvm = vcpu_e500->vcpu.kvm; + + /* used to check for invalidations in progress */ + mmu_seq = kvm->mmu_notifier_seq; + smp_rmb(); /* * Translate guest physical to true physical, acquiring @@ -458,6 +464,13 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500, (long)gfn, pfn); return -EINVAL; } + + spin_lock(&kvm->mmu_lock); + if (mmu_notifier_retry(kvm, mmu_seq)) { + ret = -EAGAIN; + goto out; + } + kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg); kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize, @@ -466,10 +479,12 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500, /* Clear i-cache for new pages */ kvmppc_mmu_flush_icache(pfn); +out: + spin_unlock(&kvm->mmu_lock); /* Drop refcount on page, so that mmu notifiers can clear it */ kvm_release_pfn_clean(pfn); - return 0; + return ret; } /* XXX only map the one-one case, for now use TLB0 */