diff options
| author | Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2016-10-05 20:09:33 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-16 19:03:38 +0300 |
| commit | 88540ad0820ddfb05626e0136c0e5a79cea85fd1 (patch) | |
| tree | b9e4cdc2b5ca91c2e3d03dd864f810c6a035ebb9 /arch/x86 | |
| parent | c64c7600e60086b658250b9f80b18cb959ed7b0f (diff) | |
| download | linux-88540ad0820ddfb05626e0136c0e5a79cea85fd1.tar.xz | |
xen/x86: Update topology map for PV VCPUs
commit a6a198bc60e6c980a56eca24d33dc7f29139f8ea upstream.
Early during boot topology_update_package_map() computes
logical_pkg_ids for all present processors.
Later, when processors are brought up, identify_cpu() updates
these values based on phys_pkg_id which is a function of
initial_apicid. On PV guests the latter may point to a
non-existing node, causing logical_pkg_ids to be set to -1.
Intel's RAPL uses logical_pkg_id (as topology_logical_package_id())
to index its arrays and therefore in this case will point to index
65535 (since logical_pkg_id is a u16). This could lead to either a
crash or may actually access random memory location.
As a workaround, we recompute topology during CPU bringup to reset
logical_pkg_id to a valid value.
(The reason for initial_apicid being bogus is because it is
initial_apicid of the processor from which the guest is launched.
This value is CPUID(1).EBX[31:24])
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/xen/smp.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 0b4d04c8ab4d..62284035be84 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -87,6 +87,12 @@ static void cpu_bringup(void) cpu_data(cpu).x86_max_cores = 1; set_cpu_sibling_map(cpu); + /* + * identify_cpu() may have set logical_pkg_id to -1 due + * to incorrect phys_proc_id. Let's re-comupte it. + */ + topology_update_package_map(apic->cpu_present_to_apicid(cpu), cpu); + xen_setup_cpu_clockevents(); notify_cpu_starting(cpu); |