From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x22d.google.com (mail-pa0-x22d.google.com [IPv6:2607:f8b0:400e:c03::22d]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id B0D4D1A032A for ; Mon, 28 Jul 2014 16:05:36 +1000 (EST) Received: by mail-pa0-f45.google.com with SMTP id eu11so9817799pac.18 for ; Sun, 27 Jul 2014 23:05:34 -0700 (PDT) From: Liu Ping Fan To: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org Subject: [PATCH] powerpc: kvm: make the setup of hpte under the protection of KVMPPC_RMAP_LOCK_BIT Date: Mon, 28 Jul 2014 14:09:04 +0800 Message-Id: <1406527744-25316-1-git-send-email-pingfank@linux.vnet.ibm.com> Cc: Paul Mackerras , Alexander Graf List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , In current code, the setup of hpte is under the risk of race with mmu_notifier_invalidate, i.e we may setup a hpte with a invalid pfn. Resolve this issue by sync the two actions by KVMPPC_RMAP_LOCK_BIT. Signed-off-by: Liu Ping Fan --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 8056107..e6dcff4 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -754,19 +754,24 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, if (hptep[0] & HPTE_V_VALID) { /* HPTE was previously valid, so we need to invalidate it */ - unlock_rmap(rmap); hptep[0] |= HPTE_V_ABSENT; kvmppc_invalidate_hpte(kvm, hptep, index); /* don't lose previous R and C bits */ r |= hptep[1] & (HPTE_R_R | HPTE_R_C); + + hptep[1] = r; + eieio(); + hptep[0] = hpte[0]; + asm volatile("ptesync" : : : "memory"); + unlock_rmap(rmap); } else { + hptep[1] = r; + eieio(); + hptep[0] = hpte[0]; + asm volatile("ptesync" : : : "memory"); kvmppc_add_revmap_chain(kvm, rev, rmap, index, 0); } - hptep[1] = r; - eieio(); - hptep[0] = hpte[0]; - asm volatile("ptesync" : : : "memory"); preempt_enable(); if (page && hpte_is_writable(r)) SetPageDirty(page); -- 1.8.1.4