We need to fall back from logical-flat APIC mode to physical-flat mode
when we have more than 8 CPUs. However, in the presence of CPU
hotplug(with bios listing not enabled but possible cpus as disabled cpus in
MADT), we have to consider the number of possible CPUs rather than
the number of current CPUs; otherwise we may cross the 8-CPU boundary
when CPUs are added later.
32bit apic code can use more cleanups (like the removal of vendor checks in
32bit default_setup_apic_routing()) and more unifications with 64bit code.
Yinghai has some patches in works already. This patch addresses the boot issue
that is reported in the virtualization guest context.
[ hpa: incorporated function annotation feedback from Yinghai Lu ]
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1265767304.2833.19.camel@sbs-t61.sc.intel.com>
Acked-by: Shaohui Zheng <shaohui.zheng@intel.com>
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
We can use logical flat mode if there are <= 8 logical cpu's
(irrespective of physical apic id values). This will enable simplified
and efficient IPI and device interrupt routing on such platforms.
This has been tested to work on both Intel and AMD platforms.
Exceptions like IBM summit platform which can't use logical flat mode
are addressed by using OEM platform checks.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Chris McDermott <lcm@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert commit 2fbd07a5f5, as this commit
breaks an IBM platform with quad-core Xeon cpu's.
According to Suresh, this might be an IBM platform issue, as on other
Intel platforms with <= 8 logical cpu's, logical flat mode works fine
irespective of physical apic id values (inline with the xapic
architecture).
Revert this for now because of the IBM platform breakage.
Another version will be re-submitted after the complete analysis.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On Intel platforms, we can use logical flat mode if there are <= 8
logical cpu's (irrespective of physical apic id values). This will
enable simplified and efficient IPI and device interrupt routing on
such platforms.
Fix the relevant comments while we are at it.
We can clean up default_setup_apic_routing() by using apic->probe()
but that is a different item.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "yinghai@kernel.org" <yinghai@kernel.org>
LKML-Reference: <1253327399.3948.747.camel@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits)
ACPI, x86: expose some IO-APIC routines when CONFIG_ACPI=n
x86, apic: Slim down stack usage in early_init_lapic_mapping()
x86, ioapic: Get rid of needless check and simplify ioapic_setup_resources()
x86, ioapic: Define IO_APIC_DEFAULT_PHYS_BASE constant
x86: Fix x86_model test in es7000_apic_is_cluster()
x86, apic: Move dmar_table_init() out of enable_IR()
x86, ioapic: Panic on irq-pin binding only if needed
x86/apic: Enable x2APIC without interrupt remapping under KVM
x86, apic: Drop redundant bit assignment
x86, ioapic: Throw BUG instead of NULL dereference
x86, ioapic: Introduce for_each_irq_pin() helper
x86: Remove superfluous NULL pointer check in destroy_irq()
x86/ioapic.c: unify ioapic_retrigger_irq()
x86/ioapic.c: convert __target_IO_APIC_irq to conventional for() loop
x86/ioapic.c: clean up replace_pin_at_irq_node logic and comments
x86/ioapic.c: convert replace_pin_at_irq_node to conventional for() loop
x86/ioapic.c: simplify add_pin_to_irq_node()
x86/ioapic.c: convert io_apic_level_ack_pending loop to normal for() loop
x86/ioapic.c: move lost comment to what seems like appropriate place
x86/ioapic.c: remove redundant declaration of irq_pin_list
...
2.6.31-rc7 does not boot on vSMP systems:
[ 8.501108] CPU31: Thermal monitoring enabled (TM1)
[ 8.501127] CPU 31 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 8.650254] CPU31: Intel(R) Xeon(R) CPU E5540 @ 2.53GHz stepping 04
[ 8.710324] Brought up 32 CPUs
[ 8.713916] Total of 32 processors activated (162314.96 BogoMIPS).
[ 8.721489] ERROR: parent span is not a superset of domain->span
[ 8.727686] ERROR: domain->groups does not contain CPU0
[ 8.733091] ERROR: groups don't span domain->span
[ 8.737975] ERROR: domain->cpu_power not set
[ 8.742416]
Ravikiran Thirumalai bisected it to:
| commit 2759c3287d
| x86: don't call read_apic_id if !cpu_has_apic
The problem is that on vSMP systems the CPUID derived
initial-APICIDs are overlapping - so we need to fall
back on hard_smp_processor_id() which reads the local
APIC.
Both come from the hardware (influenced by firmware
though) so it's a tough call which one to trust.
Doing the quirk expresses the vSMP property properly
and also does not affect other systems, so we go for
this solution instead of a revert.
Reported-and-Tested-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shai Fultheim <shai@scalex86.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <4A944D3C.5030100@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
KVM would like to provide x2APIC interface to a guest without emulating
interrupt remapping device. The reason KVM prefers guest to use x2APIC
is that x2APIC interface is better virtualizable and provides better
performance than mmio xAPIC interface:
- msr exits are faster than mmio (no page table walk, emulation)
- no need to read back ICR to look at the busy bit
- one 64 bit ICR write instead of two 32 bit writes
- shared code with the Hyper-V paravirt interface
Included patch changes x2APIC enabling logic to enable it even if IR
initialization failed, but kernel runs under KVM and no apic id is
greater than 255 (if there is one spec requires BIOS to move to x2apic
mode before starting an OS).
-v2: fix build
-v3: fix bug causing compiler warning
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Sheng Yang <sheng@linux.intel.com>
Cc: "avi@redhat.com" <avi@redhat.com>
LKML-Reference: <20090720122417.GR5638@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Clean up #ifdefs and replace them with helper functions.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: interface augmentation (not yet used)
Enable fault handling flow for intr-remapping aswell. Fault handling
code now shared by both dma-remapping and intr-remapping.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Impact: cleanup
x86_quirks->update_apic() calling looks crazy. so try to remove it:
1. every apic take wakeup_cpu member directly
2. separate es7000_apic to es7000_apic_cluster
3. use uv_wakeup_cpu directly
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If BIOS hands over the control to OS in legacy xapic mode, select
legacy xapic related ops in the early apic probe and shift to x2apic
ops later in the boot sequence, only after enabling x2apic mode.
If BIOS hands over the control in x2apic mode, select x2apic related
ops in the early apic probe.
This fixes the early boot panic, where we were selecting x2apic ops,
while the cpu is still in legacy xapic mode.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move the 32-bit extended-arch APIC drivers to arch/x86/kernel/apic/
too, and rename apic_64.c to probe_64.c.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
