The git commit d5aaffa9dd
(cpufreq: handle cpufreq being disabled for all exported function)
tightens the cpufreq API by returning errors when disable_cpufreq()
had been called.
The problem we are hitting is that the module xen-acpi-processor which
uses the ACPI's functions: acpi_processor_register_performance,
acpi_processor_preregister_performance, and acpi_processor_notify_smm
fails at acpi_processor_register_performance with -22.
Note that earlier during bootup in arch/x86/xen/setup.c there is also
an call to cpufreq's API: disable_cpufreq().
This is b/c we want the Linux kernel to parse the ACPI data, but leave
the cpufreq decisions to the hypervisor.
In v3.9 all the checks that d5aaffa9dd
added are now hit and the calls to cpufreq_register_notifier will now
fail. This means that acpi_processor_ppc_init ends up printing:
"Warning: Processor Platform Limit not supported"
and the acpi_processor_ppc_status is not set.
The repercussions of that is that the call to
acpi_processor_register_performance fails right away at:
if (!(acpi_processor_ppc_status & PPC_REGISTERED))
and we don't progress any further on parsing and extracting the _P*
objects.
The only reason the Xen code called that function was b/c it was
exported and the only way to gather the P-states. But we can also
just make acpi_processor_get_performance_info be exported and not
use acpi_processor_register_performance. This patch does so.
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Remove the unused power field from struct struct acpi_processor_cx.
[rjw: Modified changelog.]
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Coverity points out that we do not free in one case the
pr_backup - and sure enough we forgot.
Found by Coverity (CID 401970)
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This file depends on <xen/xen.h>, but the dependency was hidden due
to: <asm/acpi.h> -> <asm/trampoline.h> -> <asm/io.h> -> <xen/xen.h>
With the removal of <asm/trampoline.h>, this exposed the missing
Reported-by: Ingo Molnar <mingo@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
We did a similar check for the P-states but did not do it for
the C-states. What we want to do is ignore cases where the DSDT
has definition for sixteen CPUs, but the machine only has eight
CPUs and we get:
xen-acpi-processor: (CX): Hypervisor error (-22) for ACPI CPU14
Reported-by: Tobias Geiger <tobias.geiger@vido.info>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
When booting the kernel under machines that do not have P-states
we would end up with:
------------[ cut here ]------------
WARNING: at drivers/xen/xen-acpi-processor.c:504
xen_acpi_processor_init+0x286/0
x2e0()
Hardware name: ProLiant BL460c G6
Modules linked in:
Pid: 1, comm: swapper Not tainted 2.6.39-200.0.3.el5uek #1
Call Trace:
[<ffffffff8191d056>] ? xen_acpi_processor_init+0x286/0x2e0
[<ffffffff81068300>] warn_slowpath_common+0x90/0xc0
[<ffffffff8191cdd0>] ? check_acpi_ids+0x1e0/0x1e0
[<ffffffff8106834a>] warn_slowpath_null+0x1a/0x20
[<ffffffff8191d056>] xen_acpi_processor_init+0x286/0x2e0
[<ffffffff8191cdd0>] ? check_acpi_ids+0x1e0/0x1e0
[<ffffffff81002168>] do_one_initcall+0xe8/0x130
.. snip..
Which is OK - the machines do not have P-states, so we fail to register
to process the _PXX states. But there is no need to WARN the user
of it.
Oracle BZ# 13871288
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This driver solves three problems:
1). Parse and upload ACPI0007 (or PROCESSOR_TYPE) information to the
hypervisor - aka P-states (cpufreq data).
2). Upload the the Cx state information (cpuidle data).
3). Inhibit CPU frequency scaling drivers from loading.
The reason for wanting to solve 1) and 2) is such that the Xen hypervisor
is the only one that knows the CPU usage of different guests and can
make the proper decision of when to put CPUs and packages in proper states.
Unfortunately the hypervisor has no support to parse ACPI DSDT tables, hence it
needs help from the initial domain to provide this information. The reason
for 3) is that we do not want the initial domain to change P-states while the
hypervisor is doing it as well - it causes rather some funny cases of P-states
transitions.
For this to work, the driver parses the Power Management data and uploads said
information to the Xen hypervisor. It also calls acpi_processor_notify_smm()
to inhibit the other CPU frequency scaling drivers from being loaded.
Everything revolves around the 'struct acpi_processor' structure which
gets updated during the bootup cycle in different stages. At the startup, when
the ACPI parser starts, the C-state information is processed (processor_idle)
and saved in said structure as 'power' element. Later on, the CPU frequency
scaling driver (powernow-k8 or acpi_cpufreq), would call the the
acpi_processor_* (processor_perflib functions) to parse P-states information
and populate in the said structure the 'performance' element.
Since we do not want the CPU frequency scaling drivers from loading
we have to call the acpi_processor_* functions to parse the P-states and
call "acpi_processor_notify_smm" to stop them from loading.
There is also one oddity in this driver which is that under Xen, the
physical online CPU count can be different from the virtual online CPU count.
Meaning that the macros 'for_[online|possible]_cpu' would process only
up to virtual online CPU count. We on the other hand want to process
the full amount of physical CPUs. For that, the driver checks if the ACPI IDs
count is different from the APIC ID count - which can happen if the user
choose to use dom0_max_vcpu argument. In such a case a backup of the PM
structure is used and uploaded to the hypervisor.
[v1-v2: Initial RFC implementations that were posted]
[v3: Changed the name to passthru suggested by Pasi Kärkkäinen <pasik@iki.fi>]
[v4: Added vCPU != pCPU support - aka dom0_max_vcpus support]
[v5: Cleaned up the driver, fix bug under Athlon XP]
[v6: Changed the driver to a CPU frequency governor]
[v7: Jan Beulich <jbeulich@suse.com> suggestion to make it a cpufreq scaling driver
made me rework it as driver that inhibits cpufreq scaling driver]
[v8: Per Jan's review comments, fixed up the driver]
[v9: Allow to continue even if acpi_processor_preregister_perf.. fails]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
