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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 1f12e32f4c ("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>
This commit is contained in:
Boris Ostrovsky 2016-03-17 09:03:24 -04:00 committed by Konrad Rzeszutek Wilk
parent e01dc539df
commit ed6069be72
1 changed files with 10 additions and 2 deletions
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12
arch/x86/xen/apic.c
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@ -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 */