| Message ID | 1458219805-13197-2-git-send-email-boris.ostrovsky@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Mar 17, 2016 at 09:03:24AM -0400, Boris Ostrovsky wrote: > 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> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > --- > 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 >
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 */
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> --- arch/x86/xen/apic.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-)