linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: ke.yu@intel.com, kevin.tian@intel.com, JBeulich@novell.com,
	linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
	lenb@kernel.org
Cc: xen-devel@lists.xensource.com,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH] processor passthru - upload _Cx and _Pxx data to hypervisor (v5).
Date: Thu, 23 Feb 2012 17:31:07 -0500	[thread overview]
Message-ID: <1330036270-20015-1-git-send-email-konrad.wilk@oracle.com> (raw)

The problem these three patches try to solve is to provide ACPI power management
information to the Xen hypervisor. The hypervisor lacks the ACPI DSDT parser so it can't
get that data without some help - and the initial domain can provide that. One
approach (https://lkml.org/lkml/2011/11/30/245) augments the ACPI code to call
an external PM code - but there were no comments about it so I decided to see
if another approach could solve it.

This module (processor-passthru)  collects the information that the cpufreq
drivers and the ACPI processor code save in the 'struct acpi_processor' and
then uploads it to the hypervisor.

The driver can be either an module or compiled in. In either mode the driver
launches a thread that checks whether an cpufreq driver is registered. If so
it reads all the 'struct acpi_processor' data for all online CPUs and sends
it to hypervisor. The driver also register a CPU hotplug component - so if a new
CPU shows up - it would send the data to the hypervisor for it as well.
Furthermore it also verifies whether the ACPI ID count is different than what
the kernel sees (which is possible with dom0_max_vcpus) and if so uploads
the data for the other ACPI IDs.

The patches are available in this git tree:

git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/processor-passthru.v5


Konrad Rzeszutek Wilk (3):
      xen/setup/pm/acpi: Remove the call to boot_option_idle_override.
      xen/enlighten: Expose MWAIT and MWAIT_LEAF if hypervisor OKs it.
      xen/processor-passthru: Provide an driver that passes struct acpi_processor data to the hypervisor.

 arch/x86/xen/enlighten.c         |   92 +++++++-
 arch/x86/xen/setup.c             |    1 -
 drivers/xen/Kconfig              |   14 +
 drivers/xen/Makefile             |    2 +-
 drivers/xen/processor-passthru.c |  485 ++++++++++++++++++++++++++++++++++++++
 include/xen/interface/platform.h |    4 +-
 6 files changed, 594 insertions(+), 4 deletions(-)


P.S.
On the hypervisor side, it requires this patch on AMD:
# HG changeset patch
# Parent aea8cfac8cf1afe397f2e1d422a852008d8a83fe
traps: AMD PM RDMSRs (MSR_K8_PSTATE_CTRL, etc)

The restriction to read and write the AMD power management MSRs is gated if the
domain 0 is the PM domain (so FREQCTL_dom0_kernel is set). But we can
relax this restriction and allow the privileged domain to read the MSRs
(but not write). This allows the priviliged domain to harvest the power
management information (ACPI _PSS states) and send it to the hypervisor.

This patch works fine with older classic dom0 (2.6.32) and with
AMD K7 and K8 boxes.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff -r aea8cfac8cf1 xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c	Thu Feb 23 13:23:02 2012 -0500
+++ b/xen/arch/x86/traps.c	Thu Feb 23 13:29:00 2012 -0500
@@ -2484,7 +2484,7 @@ static int emulate_privileged_op(struct 
         case MSR_K8_PSTATE7:
             if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD )
                 goto fail;
-            if ( !is_cpufreq_controller(v->domain) )
+            if ( !is_cpufreq_controller(v->domain) && !IS_PRIV(v->domain) )
             {
                 regs->eax = regs->edx = 0;
                 break;



             reply	other threads:[~2012-02-23 22:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-23 22:31 Konrad Rzeszutek Wilk [this message]
2012-02-23 22:31 ` [PATCH 1/3] xen/setup/pm/acpi: Remove the call to boot_option_idle_override Konrad Rzeszutek Wilk
2012-02-23 22:31 ` [PATCH 2/3] xen/enlighten: Expose MWAIT and MWAIT_LEAF if hypervisor OKs it Konrad Rzeszutek Wilk
2012-02-24 10:32   ` Jan Beulich
2012-02-24 23:52     ` Konrad Rzeszutek Wilk
2012-02-27  8:14       ` Jan Beulich
2012-02-23 22:31 ` [PATCH 3/3] xen/processor-passthru: Provide an driver that passes struct acpi_processor data to the hypervisor Konrad Rzeszutek Wilk
2012-02-24 10:23 ` [PATCH] processor passthru - upload _Cx and _Pxx data to hypervisor (v5) Jan Beulich
2012-02-24 15:08   ` Konrad Rzeszutek Wilk
2012-02-25  0:21   ` Konrad Rzeszutek Wilk
2012-02-27  8:19     ` Jan Beulich

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1330036270-20015-1-git-send-email-konrad.wilk@oracle.com \
    --to=konrad.wilk@oracle.com \
    --cc=JBeulich@novell.com \
    --cc=ke.yu@intel.com \
    --cc=kevin.tian@intel.com \
    --cc=lenb@kernel.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=xen-devel@lists.xensource.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).