The x2apic_preenabled flag is just a horrible hack and if X2APIC
support is disabled it does not reflect the actual hardware
state. Check the hardware instead.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.541280622@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
No point in having a static variable around which is always 0. Let the
compiler optimize code out if disabled.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.363274310@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
enable_IR_x2apic() grew a open coded x2apic detection. Implement a
proper helper function which shares the code with the already existing
x2apic_enabled().
Made it use rdmsrl_safe as suggested by Boris.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.285038186@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull x86/apic updates from Thomas Gleixner:
"This is a major overhaul to the x86 apic subsystem consisting of the
following parts:
- Remove obsolete APIC driver abstractions (David Rientjes)
- Use the irqdomain facilities to dynamically allocate IRQs for
IOAPICs. This is a prerequisite to enable IOAPIC hotplug support,
and it also frees up wasted vectors (Jiang Liu)
- Misc fixlets.
Despite the hickup in Ingos previous pull request - caused by the
missing fixup for the suspend/resume issue reported by Borislav - I
strongly recommend that this update finds its way into 3.17. Some
history for you:
This is preparatory work for physical IOAPIC hotplug. The first
attempt to support this was done by Yinghai and I shot it down because
it just added another layer of obscurity and complexity to the already
existing mess without tackling the underlying shortcomings of the
current implementation.
After quite some on- and offlist discussions, I requested that the
design of this functionality must use generic infrastructure, i.e.
irq domains, which provide all the mechanisms to dynamically map linux
interrupt numbers to physical interrupts.
Jiang picked up the idea and did a great job of consolidating the
existing interfaces to manage the x86 (IOAPIC) interrupt system by
utilizing irq domains.
The testing in tip, Linux-next and inside of Intel on various machines
did not unearth any oddities until Borislav exposed it to one of his
oddball machines. The issue was resolved quickly, but unfortunately
the fix fell through the cracks and did not hit the tip tree before
Ingo sent the pull request. Not entirely Ingos fault, I also assumed
that the fix was already merged when Ingo asked me whether he could
send it.
Nevertheless this work has a proper design, has undergone several
rounds of review and the final fallout after applying it to tip and
integrating it into Linux-next has been more than moderate. It's the
ground work not only for IOAPIC hotplug, it will also allow us to move
the lowlevel vector allocation into the irqdomain hierarchy, which
will benefit other architectures as well. Patches are posted already,
but they are on hold for two weeks, see below.
I really appreciate the competence and responsiveness Jiang has shown
in course of this endavour. So I'm sure that any fallout of this will
be addressed in a timely manner.
FYI, I'm vanishing for 2 weeks into my annual kids summer camp kitchen
duty^Wvacation, while you folks are drooling at KS/LinuxCon :) But HPA
will have a look at the hopefully zero fallout until I'm back"
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
x86, irq, PCI: Keep IRQ assignment for PCI devices during suspend/hibernation
x86/apic/vsmp: Make is_vsmp_box() static
x86, apic: Remove enable_apic_mode callback
x86, apic: Remove setup_portio_remap callback
x86, apic: Remove multi_timer_check callback
x86, apic: Replace noop_check_apicid_used
x86, apic: Remove check_apicid_present callback
x86, apic: Remove mps_oem_check callback
x86, apic: Remove smp_callin_clear_local_apic callback
x86, apic: Replace trampoline physical addresses with defaults
x86, apic: Remove x86_32_numa_cpu_node callback
x86: intel-mid: Use the new io_apic interfaces
x86, vsmp: Remove is_vsmp_box() from apic_is_clustered_box()
x86, irq: Clean up irqdomain transition code
x86, irq, devicetree: Release IOAPIC pin when PCI device is disabled
x86, irq, SFI: Release IOAPIC pin when PCI device is disabled
x86, irq, mpparse: Release IOAPIC pin when PCI device is disabled
x86, irq, ACPI: Release IOAPIC pin when PCI device is disabled
x86, irq: Introduce helper functions to release IOAPIC pin
x86, irq: Simplify the way to handle ISA IRQ
...
Since commit b5660ba76b ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the mps_oem_check() apic callback has been obsolete. Remove it.
This allows generic_mps_oem_check() to be removed as well.
Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302349390.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The trampoline_phys_{high,low} members of struct apic are always
initialized to DEFAULT_TRAMPOLINE_PHYS_HIGH and TRAMPOLINE_PHYS_LOW,
respectively. Hardwire the constants and remove the unneeded members.
Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302348330.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
When a vSMP Foundation box is detected, the function apic_cluster_num() counts
the number of APIC clusters found. If more than one found, a multi board
configuration is assumed, and TSC marked as unstable. This behavior is
incorrect as vSMP Foundation may use processors from single node only, attached
to memory of other nodes - and such node may have more than one APIC cluster
(typically any recent intel box has more than single APIC_CLUSTERID(x)).
To fix this, we simply remove the code which detects a vSMP Foundation box and
affects apic_is_clusted_box() return value. This can be done because later the
kernel checks by itself if the TSC is stable using the
check_tsc_sync_[source|target]() functions and marks TSC as unstable if needed.
Acked-by: Shai Fultheim <shai@scalemp.com>
Signed-off-by: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1404036068-11674-1-git-send-email-oren@scalemp.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Simplify arch/x86/include/asm/mpspec.h by
1) Change max_physical_apicid to static as it's only used in apic.c.
2) Kill declaration of mpc_default_type, it's never defined.
3) Delete default_acpi_madt_oem_check(), it has already been declared
in apic.h.
4) Make default_acpi_madt_oem_check() depends on CONFIG_X86_LOCAL_APIC
instead of CONFIG_X86_64 to support i386.
5) Change mp_override_legacy_irq(), mp_config_acpi_legacy_irqs() and
mp_register_gsi() as static because they are only used in acpi/boot.c.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1402302011-23642-4-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
X86_FEATURE_FXSAVE_LEAK, X86_FEATURE_11AP and
X86_FEATURE_CLFLUSH_MONITOR are not really features but synthetic bits
we use for applying different bug workarounds. Call them what they
really are, and make sure they get the proper cross-CPU behavior (OR
rather than AND).
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1403042783-23278-1-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The "nox2apic" variable can be defined as __initdata since it is
only used for bootstrap. It can now unconditionally be defined
since it will later be freed.
At the same time, it is also better off as a bool.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042354380.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that there is only a single wait_for_init_deassert()
function, just convert the member of struct apic to a bool to
determine whether we need to wait for init_deassert to become
non-zero.
There are no more callers of default_wait_for_init_deassert(),
so fold it into the caller.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042354010.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
es7000_wait_for_init_deassert() is functionally equivalent to
default_wait_for_init_deassert(), so remove the duplicate code
and use only a single function.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042353030.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Prevent crash_kexec() from deadlocking on ioapic_lock. When
crash_kexec() is executed on a CPU, the CPU will take ioapic_lock
in disable_IO_APIC(). So if the cpu gets an NMI while locking
ioapic_lock, a deadlock will happen.
In this patch, ioapic_lock is zapped/initialized before disable_IO_APIC().
You can reproduce this deadlock the following way:
1. Add mdelay(1000) after raw_spin_lock_irqsave() in
native_ioapic_set_affinity()@arch/x86/kernel/apic/io_apic.c
Although the deadlock can occur without this modification, it will increase
the potential of the deadlock problem.
2. Build and install the kernel
3. Set up the OS which will run panic() and kexec when NMI is injected
# echo "kernel.unknown_nmi_panic=1" >> /etc/sysctl.conf
# vim /etc/default/grub
add "nmi_watchdog=0 crashkernel=256M" in GRUB_CMDLINE_LINUX line
# grub2-mkconfig
4. Reboot the OS
5. Run following command for each vcpu on the guest
# while true; do echo <CPU num> > /proc/irq/<IO-APIC-edge or IO-APIC-fasteoi>/smp_affinitity; done;
By running this command, cpus will get ioapic_lock for setting affinity.
6. Inject NMI (push a dump button or execute 'virsh inject-nmi <domain>' if you
use VM). After injecting NMI, panic() is called in an nmi-handler context.
Then, kexec will normally run in panic(), but the operation will be stopped
by deadlock on ioapic_lock in crash_kexec()->machine_crash_shutdown()->
native_machine_crash_shutdown()->disable_IO_APIC()->clear_IO_APIC()->
clear_IO_APIC_pin()->ioapic_read_entry().
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20130820070107.28245.83806.stgit@yunodevel
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When implementing tracepoints in interrupt handers, if the tracepoints are
simply added in the performance sensitive path of interrupt handers,
it may cause potential performance problem due to the time penalty.
To solve the problem, an idea is to prepare non-trace/trace irq handers and
switch their IDTs at the enabling/disabling time.
So, let's introduce entering_irq()/exiting_irq() for pre/post-
processing of each irq handler.
A way to use them is as follows.
Non-trace irq handler:
smp_irq_handler()
{
entering_irq(); /* pre-processing of this handler */
__smp_irq_handler(); /*
* common logic between non-trace and trace handlers
* in a vector.
*/
exiting_irq(); /* post-processing of this handler */
}
Trace irq_handler:
smp_trace_irq_handler()
{
entering_irq(); /* pre-processing of this handler */
trace_irq_entry(); /* tracepoint for irq entry */
__smp_irq_handler(); /*
* common logic between non-trace and trace handlers
* in a vector.
*/
trace_irq_exit(); /* tracepoint for irq exit */
exiting_irq(); /* post-processing of this handler */
}
If tracepoints can place outside entering_irq()/exiting_irq() as follows,
it looks cleaner.
smp_trace_irq_handler()
{
trace_irq_entry();
smp_irq_handler();
trace_irq_exit();
}
But it doesn't work.
The problem is with irq_enter/exit() being called. They must be called before
trace_irq_enter/exit(), because of the rcu_irq_enter() must be called before
any tracepoints are used, as tracepoints use rcu to synchronize.
As a possible alternative, we may be able to call irq_enter() first as follows
if irq_enter() can nest.
smp_trace_irq_hander()
{
irq_entry();
trace_irq_entry();
smp_irq_handler();
trace_irq_exit();
irq_exit();
}
But it doesn't work, either.
If irq_enter() is nested, it may have a time penalty because it has to check if it
was already called or not. The time penalty is not desired in performance sensitive
paths even if it is tiny.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C3238D.9040706@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Pull x86/mm changes from Peter Anvin:
"The big change here is the patchset by Alex Shi to use INVLPG to flush
only the affected pages when we only need to flush a small page range.
It also removes the special INVALIDATE_TLB_VECTOR interrupts (32
vectors!) and replace it with an ordinary IPI function call."
Fix up trivial conflicts in arch/x86/include/asm/apic.h (added code next
to changed line)
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tlb: Fix build warning and crash when building for !SMP
x86/tlb: do flush_tlb_kernel_range by 'invlpg'
x86/tlb: replace INVALIDATE_TLB_VECTOR by CALL_FUNCTION_VECTOR
x86/tlb: enable tlb flush range support for x86
mm/mmu_gather: enable tlb flush range in generic mmu_gather
x86/tlb: add tlb_flushall_shift knob into debugfs
x86/tlb: add tlb_flushall_shift for specific CPU
x86/tlb: fall back to flush all when meet a THP large page
x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range
x86/tlb_info: get last level TLB entry number of CPU
x86: Add read_mostly declaration/definition to variables from smp.h
x86: Define early read-mostly per-cpu macros
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Merge tag 'kvm-3.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Avi Kivity:
"Highlights include
- full big real mode emulation on pre-Westmere Intel hosts (can be
disabled with emulate_invalid_guest_state=0)
- relatively small ppc and s390 updates
- PCID/INVPCID support in guests
- EOI avoidance; 3.6 guests should perform better on 3.6 hosts on
interrupt intensive workloads)
- Lockless write faults during live migration
- EPT accessed/dirty bits support for new Intel processors"
Fix up conflicts in:
- Documentation/virtual/kvm/api.txt:
Stupid subchapter numbering, added next to each other.
- arch/powerpc/kvm/booke_interrupts.S:
PPC asm changes clashing with the KVM fixes
- arch/s390/include/asm/sigp.h, arch/s390/kvm/sigp.c:
Duplicated commits through the kvm tree and the s390 tree, with
subsequent edits in the KVM tree.
* tag 'kvm-3.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (93 commits)
KVM: fix race with level interrupts
x86, hyper: fix build with !CONFIG_KVM_GUEST
Revert "apic: fix kvm build on UP without IOAPIC"
KVM guest: switch to apic_set_eoi_write, apic_write
apic: add apic_set_eoi_write for PV use
KVM: VMX: Implement PCID/INVPCID for guests with EPT
KVM: Add x86_hyper_kvm to complete detect_hypervisor_platform check
KVM: PPC: Critical interrupt emulation support
KVM: PPC: e500mc: Fix tlbilx emulation for 64-bit guests
KVM: PPC64: booke: Set interrupt computation mode for 64-bit host
KVM: PPC: bookehv: Add ESR flag to Data Storage Interrupt
KVM: PPC: bookehv64: Add support for std/ld emulation.
booke: Added crit/mc exception handler for e500v2
booke/bookehv: Add host crit-watchdog exception support
KVM: MMU: document mmu-lock and fast page fault
KVM: MMU: fix kvm_mmu_pagetable_walk tracepoint
KVM: MMU: trace fast page fault
KVM: MMU: fast path of handling guest page fault
KVM: MMU: introduce SPTE_MMU_WRITEABLE bit
KVM: MMU: fold tlb flush judgement into mmu_spte_update
...
This reverts commit f9808b7fd4.
After commit 'kvm: switch to apic_set_eoi_write, apic_write'
the stubs are no longer needed as kvm does not look at apicdrivers anymore.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM PV EOI optimization overrides eoi_write apic op with its own
version. Add an API for this to avoid meddling with core x86 apic driver
data structures directly.
For KVM use, we don't need any guarantees about when the switch to the
new op will take place, so it could in theory use this API after SMP init,
but it currently doesn't, and restricting callers to early init makes it
clear that it's safe as it won't race with actual APIC driver use.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
For the x2apic cluster mode, vector for an interrupt is
currently reserved on all the cpu's that are part of the x2apic
cluster. But the interrupts will be routed only to the cluster
(derived from the first cpu in the mask) members specified in
the mask. So there is no need to reserve the vector in the
unused cluster members.
Modify __assign_irq_vector() to reserve the vectors based on the
user specified irq destination mask. If the new mask is a proper
subset of the currently used mask, cleanup the vector allocation
on the unused cpu members.
Also, allow the apic driver to tune the vector domain based on
the affinity mask (which in most cases is the user-specified
mask).
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/1340656709-11423-3-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently __assign_irq_vector() goes through each cpu in the
specified mask until it finds a free vector in all the cpu's
that are part of the same interrupt domain. We visit all the
interrupt domain sibling cpus to reserve the free vector. So,
when we fail to find a free vector in an interrupt domain, it is
safe to continue our search with a cpu belonging to a new
interrupt domain. No need to go through each cpu, if the domain
containing that cpu is already visited.
Use the irq_cfg's old_domain to track the visited domains and
optimize the cpu traversal while finding a free vector in the
given cpumask.
NOTE: We can also optimize the search by using for_each_cpu() and
skip the current cpu, if it is not the first cpu in the mask
returned by the vector_allocation_domain(). But re-using the
cfg->old_domain to track the visited domains will be slightly
faster.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/1340656709-11423-2-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On UP i386, when APIC is disabled
# CONFIG_X86_UP_APIC is not set
# CONFIG_PCI_IOAPIC is not set
code looking at apicdrivers never has any effect but it
still gets compiled in. In particular, this causes
build failures with kvm, but it generally bloats the kernel
unnecessarily.
Fix by defining both __apicdrivers and __apicdrivers_end
to be NULL when CONFIG_X86_LOCAL_APIC is unset: I verified
that as the result any loop scanning __apicdrivers gets optimized out by
the compiler.
Warning: a .config with apic disabled doesn't seem to boot
for me (even without this patch). Still verifying why,
meanwhile this patch is compile-tested only.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Since there are only two locations where cpu_mask_to_apicid() is
called from, remove the operation and use only
cpu_mask_to_apicid_and() instead.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Suggested-and-acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120614074935.GE3383@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add "read-mostly" qualifier to the following variables in
smp.h:
- cpu_sibling_map
- cpu_core_map
- cpu_llc_shared_map
- cpu_llc_id
- cpu_number
- x86_cpu_to_apicid
- x86_bios_cpu_apicid
- x86_cpu_to_logical_apicid
As long as all the variables above are only written during the
initialization, this change is meant to prevent the false
sharing. More specifically, on vSMP Foundation platform
x86_cpu_to_apicid shared the same internode_cache_line with
frequently written lapic_events.
From the analysis of the first 33 per_cpu variables out of 219
(memories they describe, to be more specific) the 8 have read_mostly
nature (tlb_vector_offset, cpu_loops_per_jiffy, xen_debug_irq, etc.)
and 25 are frequently written (irq_stack_union, gdt_page,
exception_stacks, idt_desc, etc.).
Assuming that the spread of the rest of the per_cpu variables is
similar, identifying the read mostly memories will make more sense
in terms of long-term code maintenance comparing to identifying
frequently written memories.
Signed-off-by: Vlad Zolotarov <vlad@scalemp.com>
Acked-by: Shai Fultheim <shai@scalemp.com>
Cc: Shai Fultheim (Shai@ScaleMP.com) <Shai@scalemp.com>
Cc: ido@wizery.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1719258.EYKzE4Zbq5@vlad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently cpu_mask_to_apicid() should not get a offline CPU with
the cpumask. Otherwise some apic drivers might try to access
non-existent per-cpu variables (i.e. x2apic). In that regard
cpu_mask_to_apicid() and cpu_mask_to_apicid_and() operations are
inconsistent.
This fix makes the two operations do not rely on calling
functions and always return the apicid for only online CPUs. As
result, the meaning and implementations of cpu_mask_to_apicid()
and cpu_mask_to_apicid_and() operations become straight.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131624.GG4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Current cpu_mask_to_apicid() and cpu_mask_to_apicid_and()
implementations have few shortcomings:
1. A value returned by cpu_mask_to_apicid() is written to
hardware registers unconditionally. Should BAD_APICID get ever
returned it will be written to a hardware too. But the value of
BAD_APICID is not universal across all hardware in all modes and
might cause unexpected results, i.e. interrupts might get routed
to CPUs that are not configured to receive it.
2. Because the value of BAD_APICID is not universal it is
counter- intuitive to return it for a hardware where it does not
make sense (i.e. x2apic).
3. cpu_mask_to_apicid_and() operation is thought as an
complement to cpu_mask_to_apicid() that only applies a AND mask
on top of a cpumask being passed. Yet, as consequence of 18374d8
commit the two operations are inconsistent in that of:
cpu_mask_to_apicid() should not get a offline CPU with the cpumask
cpu_mask_to_apicid_and() should not fail and return BAD_APICID
These limitations are impossible to realize just from looking at
the operations prototypes.
Most of these shortcomings are resolved by returning a error
code instead of BAD_APICID. As the result, faults are reported
back early rather than possibilities to cause a unexpected
behaviour exist (in case of [1]).
The only exception is setup_timer_IRQ0_pin() routine. Although
obviously controversial to this fix, its existing behaviour is
preserved to not break the fragile check_timer() and would
better addressed in a separate fix.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131559.GF4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In case of static vector allocation domains (i.e. flat) if all
vector numbers are exhausted, an attempt to assign a new vector
will lead to useless scans through all CPUs in the cpumask, even
though it is known that each new pass would fail. Make this
corner case less painful by letting report whether the vector
allocation domain depends on passed arguments or not and stop
scanning early.
The same could have been achived by introducing a static flag to
the apic operations. But let's allow vector_allocation_domain()
have more intelligence here and decide dynamically, in case we
would need it in the future.
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131542.GE4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We know both register and value for eoi beforehand,
so there's no need to check it and no need to do math
to calculate the msr. Saves instructions/branches
on each EOI when using x2apic.
I looked at the objdump output to verify that the
generated code looks right and actually is shorter.
The real improvemements will be on the KVM guest side
though, those come in a later patch.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/e019d1a125316f10d3e3a4b2f6bda41473f4fb72.1337184153.git.mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add eoi_write callback so that kvm can override
eoi accesses without touching the rest of the apic.
As a side-effect, this will enable a micro-optimization
for apics using msr.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/0df425d746c49ac2ecc405174df87752869629d2.1337184153.git.mst@redhat.com
[ tidied it up a bit ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use the symbol instead of hard-coded numbers,
now that the reason for the value is documented
where the constant is defined we don't need to
duplicate this explanation in code.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/ecbe4c79d69c172378e47e5a587ff5cd10293c9f.1337184153.git.mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 updates from Ingo Molnar.
This touches some non-x86 files due to the sanitized INLINE_SPIN_UNLOCK
config usage.
Fixed up trivial conflicts due to just header include changes (removing
headers due to cpu_idle() merge clashing with the <asm/system.h> split).
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic/amd: Be more verbose about LVT offset assignments
x86, tls: Off by one limit check
x86/ioapic: Add io_apic_ops driver layer to allow interception
x86/olpc: Add debugfs interface for EC commands
x86: Merge the x86_32 and x86_64 cpu_idle() functions
x86/kconfig: Remove CONFIG_TR=y from the defconfigs
x86: Stop recursive fault in print_context_stack after stack overflow
x86/io_apic: Move and reenable irq only when CONFIG_GENERIC_PENDING_IRQ=y
x86/apic: Add separate apic_id_valid() functions for selected apic drivers
locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage
x86/kconfig: Update defconfigs
x86: Fix excessive MSR print out when show_msr is not specified
As suggested by Suresh Siddha and Yinghai Lu:
For x2apic pre-enabled systems, apic driver is set already early
through early_acpi_boot_init()/early_acpi_process_madt()/
acpi_parse_madt()/default_acpi_madt_oem_check() path so that
apic_id_valid() checking will be sufficient during MADT and SRAT
parsing.
For non-x2apic pre-enabled systems, all apic ids should be less
than 255.
This allows us to substitute the checks in
arch/x86/kernel/acpi/boot.c::acpi_parse_x2apic() and
arch/x86/mm/srat.c::acpi_numa_x2apic_affinity_init() with
apic->apic_id_valid().
In addition we can avoid feigning the x2apic cpu feature in the
NumaChip apic code.
The following apic drivers have separate apic_id_valid()
functions which will accept x2apic type IDs :
x2apic_phys
x2apic_cluster
x2apic_uv_x
apic_numachip
Signed-off-by: Steffen Persvold <sp@numascale.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Daniel J Blueman <daniel@numascale-asia.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/1331925935-13372-1-git-send-email-sp@numascale.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move APIC ID validity check into platform APIC code, so it can
be overridden when needed. For NumaChip systems, always trust
MADT, as it's constructed with high APIC IDs.
Behaviour verifies on standard x86 systems and on NumaChip
systems with this, and compile-tested with allyesconfig.
Signed-off-by: Daniel J Blueman <daniel@numascale-asia.com>
Reviewed-by: Steffen Persvold <sp@numascale.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1331709454-27966-1-git-send-email-daniel@numascale-asia.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently "nox2apic" boot parameter was not enabling x2apic mode if the cpu,
kernel are all capable of enabling x2apic mode and the OS handover
happened in xapic mode.
However If the bios enabled x2apic prior to OS handover, using "nox2apic"
boot parameter had no effect.
If the boot cpu's apicid is < 255, enable "nox2apic" boot parameter to
disable the x2apic mode setup by the bios. This will enable the kernel to
fallback to xapic mode and bringup only the cpu's which has apic-id < 255.
-v2: fix patch error and two compiling warning
make disable_x2apic to be __init
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/CAE9FiQUeB-3uxJAMiHsz=uPWoFv5Hg1pVepz7aU6YtqOxMC-=Q@mail.gmail.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
On some of the recent Intel SNB platforms, by default bios is pre-enabling
x2apic mode in the cpu with out setting up interrupt-remapping.
This case was resulting in the kernel to panic as the cpu is already in
x2apic mode but the OS was not able to enable interrupt-remapping (which
is a pre-req for using x2apic capability).
On these platforms all the apic-ids are < 255 and the kernel can fallback to
xapic mode if the bios has not enabled interrupt-remapping (which is
mostly the case if the bios has not exported interrupt-remapping tables to the
OS).
Reported-by: Berck E. Nash <flyboy@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20111222014632.600418637@sbsiddha-desk.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LAPIC related statistics are grouped inside the per-cpu
structure irq_stat, so there is no need for icr_read_retry_count
to be a standalone per-cpu variable.
This patch moves icr_read_retry_count to where it belongs.
Suggested-y: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In the IPI delivery slow path (NMI delivery) we retry the ICR
read to check for delivery completion a limited number of times.
[ The reason for the limited retries is that some of the places
where it is used (cpu boot, kdump, etc) IPI delivery might not
succeed (due to a firmware bug or system crash, for example)
and in such a case it is better to give up and resume
execution of other code. ]
This patch adds a new entry to /proc/interrupts, RTR, which
tells user space the number of times we retried the ICR read in
the IPI delivery slow path.
This should give some insight into how well the APIC
message delivery hardware is working - if the counts are way
too large then we are hitting a (very-) slow path way too
often.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/n/tip-vzsp20lo2xdzh5f70g0eis2s@git.kernel.org
[ extended the changelog ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
lapic timer calibration can be combined with tsc in platform
specific calibration functions. if such calibration result is
obtained early, we can skip the redundant calibration loops.
Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
These warnings (generally one per CPU) are a result of
initializing x86_cpu_to_logical_apicid while apic_default is
still in use, but the check in setup_local_APIC() being done
when apic_bigsmp was already used as an override in
default_setup_apic_routing():
Overriding APIC driver with bigsmp
Enabling APIC mode: Physflat. Using 5 I/O APICs
------------[ cut here ]------------
WARNING: at .../arch/x86/kernel/apic/apic.c:1239
...
CPU 1 irqstacks, hard=f1c9a000 soft=f1c9c000
Booting Node 0, Processors #1
smpboot cpu 1: start_ip = 9e000
Initializing CPU#1
------------[ cut here ]------------
WARNING: at .../arch/x86/kernel/apic/apic.c:1239
setup_local_APIC+0x137/0x46b() Hardware name: ...
CPU1 logical APIC ID: 2 != 8
...
Fix this (for the time being, i.e. until
x86_32_early_logical_apicid() will get removed again, as Tejun
says ought to be possible) by overriding the previously stored
values at the point where the APIC driver gets overridden.
v2: Move this and the pre-existing override logic into
arch/x86/kernel/apic/bigsmp_32.c.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: <stable@kernel.org> (2.6.39 and onwards)
Link: http://lkml.kernel.org/r/4E835D16020000780005844C@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Thomas Gleixner