diff options
| author | Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2016-03-17 09:03:24 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2016-03-25 11:42:53 -0400 |
| commit | ed6069be7204541c1da532ad8bbf892e34513552 (patch) | |
| tree | 4d302ece1e1da9ce17bc9f322cc91916cd3787da | |
| parent | e01dc539df3ada9061a1097224513236b5381349 (diff) | |
| download | lwn-ed6069be7204541c1da532ad8bbf892e34513552.tar.gz lwn-ed6069be7204541c1da532ad8bbf892e34513552.zip | |
xen/apic: Provide Xen-specific version of cpu_present_to_apicid APIC op
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 <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| -rw-r--r-- | 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 abf4901c917b..db52a7fafcc2 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 */ |