Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030670AbcCQNFb (ORCPT ); Thu, 17 Mar 2016 09:05:31 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:16528 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030596AbcCQNFW (ORCPT ); Thu, 17 Mar 2016 09:05:22 -0400 From: Boris Ostrovsky To: david.vrabel@citrix.com, konrad.wilk@oracle.com Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, Boris Ostrovsky Subject: [PATCH 1/2] xen/apic: Provide Xen-specific version of cpu_present_to_apicid APIC op Date: Thu, 17 Mar 2016 09:03:24 -0400 Message-Id: <1458219805-13197-2-git-send-email-boris.ostrovsky@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1458219805-13197-1-git-send-email-boris.ostrovsky@oracle.com> References: <1458219805-13197-1-git-send-email-boris.ostrovsky@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2184 Lines: 61 Currently Xen uses default_cpu_present_to_apicid() which will always report BAD_APICID for PV guests since x86_bios_cpu_apic_id is initialised to that value and is never updated. With commit 1f12e32f4cd5 ("x86/topology: Create logical package id"), this op is now called by smp_init_package_map() when deciding whether to call topology_update_package_map() which sets cpu_data(cpu).logical_proc_id. The latter (as topology_logical_package_id(cpu)) may be used, for example, by cpu_to_rapl_pmu() as an array index. Since uninitialized logical_package_id is set to -1, the index will become 64K which is obviously problematic. While RAPL code (and any other users of logical_package_id) should be careful in their assumptions about id's validity, Xen's cpu_present_to_apicid op should still provide value consistent with its own xen_apic_read(APIC_ID). Signed-off-by: Boris Ostrovsky --- arch/x86/xen/apic.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c index abf4901..db52a7f 100644 --- a/arch/x86/xen/apic.c +++ b/arch/x86/xen/apic.c @@ -66,7 +66,7 @@ static u32 xen_apic_read(u32 reg) ret = HYPERVISOR_platform_op(&op); if (ret) - return 0; + op.u.pcpu_info.apic_id = BAD_APICID; return op.u.pcpu_info.apic_id << 24; } @@ -142,6 +142,14 @@ static void xen_silent_inquire(int apicid) { } +static int xen_cpu_present_to_apicid(int cpu) +{ + if (cpu_present(cpu)) + return xen_get_apic_id(xen_apic_read(APIC_ID)); + else + return BAD_APICID; +} + static struct apic xen_pv_apic = { .name = "Xen PV", .probe = xen_apic_probe_pv, @@ -162,7 +170,7 @@ static struct apic xen_pv_apic = { .ioapic_phys_id_map = default_ioapic_phys_id_map, /* Used on 32-bit */ .setup_apic_routing = NULL, - .cpu_present_to_apicid = default_cpu_present_to_apicid, + .cpu_present_to_apicid = xen_cpu_present_to_apicid, .apicid_to_cpu_present = physid_set_mask_of_physid, /* Used on 32-bit */ .check_phys_apicid_present = default_check_phys_apicid_present, /* smp_sanity_check needs it */ .phys_pkg_id = xen_phys_pkg_id, /* detect_ht */ -- 1.7.1