Return-Path: Received: from mail.kernel.org ([198.145.29.99]:49584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730949AbeLFOox (ORCPT ); Thu, 6 Dec 2018 09:44:53 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wei Wang , Amadeusz Juskowiak , Julian Stecklina , Suravee Suthikulpanit , Joerg Roedel , Paolo Bonzini Subject: [PATCH 4.9 026/101] svm: Add mutex_lock to protect apic_access_page_done on AMD systems Date: Thu, 6 Dec 2018 15:38:25 +0100 Message-Id: <20181206143013.086132381@linuxfoundation.org> In-Reply-To: <20181206143011.174892052@linuxfoundation.org> References: <20181206143011.174892052@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wei Wang commit 30510387a5e45bfcf8190e03ec7aa15b295828e2 upstream. There is a race condition when accessing kvm->arch.apic_access_page_done. Due to it, x86_set_memory_region will fail when creating the second vcpu for a svm guest. Add a mutex_lock to serialize the accesses to apic_access_page_done. This lock is also used by vmx for the same purpose. Signed-off-by: Wei Wang Signed-off-by: Amadeusz Juskowiak Signed-off-by: Julian Stecklina Signed-off-by: Suravee Suthikulpanit Reviewed-by: Joerg Roedel Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1333,20 +1333,23 @@ static u64 *avic_get_physical_id_entry(s static int avic_init_access_page(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; - int ret; + int ret = 0; + mutex_lock(&kvm->slots_lock); if (kvm->arch.apic_access_page_done) - return 0; + goto out; - ret = x86_set_memory_region(kvm, - APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, - APIC_DEFAULT_PHYS_BASE, - PAGE_SIZE); + ret = __x86_set_memory_region(kvm, + APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, + APIC_DEFAULT_PHYS_BASE, + PAGE_SIZE); if (ret) - return ret; + goto out; kvm->arch.apic_access_page_done = true; - return 0; +out: + mutex_unlock(&kvm->slots_lock); + return ret; } static int avic_init_backing_page(struct kvm_vcpu *vcpu)