Previous patches allow the NMI subsystem to process multipe NMI events
in one NMI. As previously discussed this can cause issues when an event
triggered another NMI but is processed in the current NMI. This causes the
next NMI to go unprocessed and become an 'unknown' NMI.
To handle this, we first have to flag whether or not the NMI handler handled
more than one event or not. If it did, then there exists a chance that
the next NMI might be already processed. Once the NMI is flagged as a
candidate to be swallowed, we next look for a back-to-back NMI condition.
This is determined by looking at the %rip from pt_regs. If it is the same
as the previous NMI, it is assumed the cpu did not have a chance to jump
back into a non-NMI context and execute code and instead handled another NMI.
If both of those conditions are true then we will swallow any unknown NMI.
There still exists a chance that we accidentally swallow a real unknown NMI,
but for now things seem better.
An optimization has also been added to the nmi notifier rountine. Because x86
can latch up to one NMI while currently processing an NMI, we don't have to
worry about executing _all_ the handlers in a standalone NMI. The idea is
if multiple NMIs come in, the second NMI will represent them. For those
back-to-back NMI cases, we have the potentail to drop NMIs. Therefore only
execute all the handlers in the second half of a detected back-to-back NMI.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1317409584-23662-5-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The NMI handlers used to rely on the notifier infrastructure. This worked
great until we wanted to support handling multiple events better.
One of the key ideas to the nmi handling is to process _all_ the handlers for
each NMI. The reason behind this switch is because NMIs are edge triggered.
If enough NMIs are triggered, then they could be lost because the cpu can
only latch at most one NMI (besides the one currently being processed).
In order to deal with this we have decided to process all the NMI handlers
for each NMI. This allows the handlers to determine if they recieved an
event or not (the ones that can not determine this will be left to fend
for themselves on the unknown NMI list).
As a result of this change it is now possible to have an extra NMI that
was destined to be received for an already processed event. Because the
event was processed in the previous NMI, this NMI gets dropped and becomes
an 'unknown' NMI. This of course will cause printks that scare people.
However, we prefer to have extra NMIs as opposed to losing NMIs and as such
are have developed a basic mechanism to catch most of them. That will be
a later patch.
To accomplish this idea, I unhooked the nmi handlers from the notifier
routines and created a new mechanism loosely based on doIRQ. The reason
for this is the notifier routines have a couple of shortcomings. One we
could't guarantee all future NMI handlers used NOTIFY_OK instead of
NOTIFY_STOP. Second, we couldn't keep track of the number of events being
handled in each routine (most only handle one, perf can handle more than one).
Third, I wanted to eventually display which nmi handlers are registered in
the system in /proc/interrupts to help see who is generating NMIs.
The patch below just implements the new infrastructure but doesn't wire it up
yet (that is the next patch). Its design is based on doIRQ structs and the
atomic notifier routines. So the rcu stuff in the patch isn't entirely untested
(as the notifier routines have soaked it) but it should be double checked in
case I copied the code wrong.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1317409584-23662-3-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Intel does not have guest/host-only bit in perf counters like AMD
does. To support GO/HO bits KVM needs to switch EVENTSELn values
(or PERF_GLOBAL_CTRL if available) at a guest entry. If a counter is
configured to count only in a guest mode it stays disabled in a host,
but VMX is configured to switch it to enabled value during guest entry.
This patch adds GO/HO tracking to Intel perf code and provides interface
for KVM to get a list of MSRs that need to be switched on a guest entry.
Only cpus with architectural PMU (v1 or later) are supported with this
patch. To my knowledge there is not p6 models with VMX but without
architectural PMU and p4 with VMX are rare and the interface is general
enough to support them if need arise.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1317816084-18026-7-git-send-email-gleb@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Replace calls to the Xen-specific xen_alloc_vm_area() and
xen_free_vm_area() functions with the generic equivalent
(alloc_vm_area() and free_vm_area()).
On x86, these were identical already.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If we want to use granted pages for AIO, changing the mappings of a user
vma and the corresponding p2m is not enough, we also need to update the
kernel mappings accordingly.
Currently this is only needed for pages that are created for user usages
through /dev/xen/gntdev. As in, pages that have been in use by the
kernel and use the P2M will not need this special mapping.
However there are no guarantees that in the future the kernel won't
start accessing pages through the 1:1 even for internal usage.
In order to avoid the complexity of dealing with highmem, we allocated
the pages lowmem.
We issue a HYPERVISOR_grant_table_op right away in
m2p_add_override and we remove the mappings using another
HYPERVISOR_grant_table_op in m2p_remove_override.
Considering that m2p_add_override and m2p_remove_override are called
once per page we use multicalls and hypercall batching.
Use the kmap_op pointer directly as argument to do the mapping as it is
guaranteed to be present up until the unmapping is done.
Before issuing any unmapping multicalls, we need to make sure that the
mapping has already being done, because we need the kmap->handle to be
set correctly.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[v1: Removed GRANT_FRAME_BIT usage]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The patch titled "x86: Don't use frame pointer to save old stack
on irq entry" did not properly adjust CFI directives, so this
patch is a follow-up to that one.
With the old stack pointer no longer stored in a callee-saved
register (plus some offset), we now have to use a CFA expression
to describe the memory location where it is being found. This
requires the use of .cfi_escape (allowing arbitrary byte streams
to be emitted into .eh_frame), as there is no
.cfi_def_cfa_expression (which also cannot reasonably be
expected, as it would require a full expression parser).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/4E8360200200007800058467@nat28.tlf.novell.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>
The note about partial registers is not really relevent now that we
rely on gcc to generate all the assembler.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.
Fix these broken references, sometimes by dropping the irrelevant text
they were part of.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This patches implements the xen_platform_op hypercall, to pass the parsed
ACPI info to hypervisor.
Signed-off-by: Yu Ke <ke.yu@intel.com>
Signed-off-by: Tian Kevin <kevin.tian@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[v1: Added DEFINE_GUEST.. in appropiate headers]
[v2: Ripped out typedefs]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This pre-defination is preparing for KVM tsc deadline timer emulation, but
theirself are not kvm specific.
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
If simultaneous NMIs happen, we're supposed to queue the second
and next (collapsing them), but currently we sometimes collapse
the second into the first.
Fix by using a counter for pending NMIs instead of a bool; since
the counter limit depends on whether the processor is currently
in an NMI handler, which can only be checked in vcpu context
(via the NMI mask), we add a new KVM_REQ_NMI to request recalculation
of the counter.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Unifiying the operands means not taking advantage of the fact that some
operand types can only go into certain operands (for example, DI can only
be used by the destination), so we need more bits to hold the operand type.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Instruction emulation for EOI writes can be skipped, since sane
guest simply uses MOV instead of string operations. This is a nice
improvement when guest doesn't support x2apic or hyper-V EOI
support.
a single VM bandwidth is observed with ~8% bandwidth improvement
(7.4Gbps->8Gbps), by saving ~5% cycles from EOI emulation.
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
<Based on earlier work from>:
Signed-off-by: Eddie Dong <eddie.dong@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
KVM assumed in several places that reading the TSC MSR returns the value for
L1. This is incorrect, because when L2 is running, the correct TSC read exit
emulation is to return L2's value.
We therefore add a new x86_ops function, read_l1_tsc, to use in places that
specifically need to read the L1 TSC, NOT the TSC of the current level of
guest.
Note that one change, of one line in kvm_arch_vcpu_load, is made redundant
by a different patch sent by Zachary Amsden (and not yet applied):
kvm_arch_vcpu_load() should not read the guest TSC, and if it didn't, of
course we didn't have to change the call of kvm_get_msr() to read_l1_tsc().
[avi: moved callback to kvm_x86_ops tsc block]
Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Acked-by: Zachary Amsdem <zamsden@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Architecturally, PDPTEs are cached in the PDPTRs when CR3 is reloaded.
On SVM, it is not possible to implement this, but on VMX this is possible
and was indeed implemented until nested SVM changed this to unconditionally
read PDPTEs dynamically. This has noticable impact when running PAE guests.
Fix by changing the MMU to read PDPTRs from the cache, falling back to
reading from memory for the nested MMU.
Signed-off-by: Avi Kivity <avi@redhat.com>
Tested-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The vmexit tracepoints format the exit_reason to make it human-readable.
Since the exit_reason depends on the instruction set (vmx or svm),
formatting is handled with ftrace_print_symbols_seq() by referring to
the appropriate exit reason table.
However, the ftrace_print_symbols_seq() function is not meant to be used
directly in tracepoints since it does not export the formatting table
which userspace tools like trace-cmd and perf use to format traces.
In practice perf dies when formatting vmexit-related events and
trace-cmd falls back to printing the numeric value (with extra
formatting code in the kvm plugin to paper over this limitation). Other
userspace consumers of vmexit-related tracepoints would be in similar
trouble.
To avoid significant changes to the kvm_exit tracepoint, this patch
moves the vmx and svm exit reason tables into arch/x86/kvm/trace.h and
selects the right table with __print_symbolic() depending on the
instruction set. Note that __print_symbolic() is designed for exporting
the formatting table to userspace and allows trace-cmd and perf to work.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The patch raises the hard limit of VCPU count to 254.
This will allow developers to easily work on scalability
and will allow users to test high VCPU setups easily without
patching the kernel.
To prevent possible issues with current setups, KVM_CAP_NR_VCPUS
now returns the recommended VCPU limit (which is still 64) - this
should be a safe value for everybody, while a new KVM_CAP_MAX_VCPUS
returns the hard limit which is now 254.
Cc: Avi Kivity <avi@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Suggested-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We dropped a lot of the MMU debugfs in favour of using
tracing API - but there is one which just provides
mostly static information that was made invisible by this change.
Bring it back.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This is a workaround for a UV2 hub bug that affects the format of system
global addresses.
The GRU API for UV2 was inadvertently broken by a hardware change. The
format of the physical address used for TLB dropins and for addresses used
with instructions running in unmapped mode has changed. This change was
not documented and became apparent only when diags failed running on
system simulators.
For UV1, TLB and GRU instruction physical addresses are identical to
socket physical addresses (although high NASID bits must be OR'ed into the
address).
For UV2, socket physical addresses need to be converted. The NODE portion
of the physical address needs to be shifted so that the low bit is in bit
39 or bit 40, depending on an MMR value.
It is not yet clear if this bug will be fixed in a silicon respin. If it
is fixed, the hub revision will be incremented & the workaround disabled.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On x86-64, they were just wasteful: with the explicitly added (now
unnecessary) padding, the size of the alternatives structure was 16
bytes, and an alignment of 8 bytes didn't hurt much.
However, it was still silly, since the natural size and alignment for
the structure is actually just 12 bytes, 4-byte aligned since commit
59e97e4d6f ("x86: Make alternative instruction pointers relative").
So removing the padding, and removing the extra alignment is just a good
idea.
On x86-32, the alignment of 4 bytes was correct, but was incorrectly
hardcoded as 8 bytes in <asm/alternative-asm.h>. That header file had
used to be an x86-64 only header file, but various unification efforts
have made it be used for x86-32 too (ie the unification of rwlock and
rwsem).
That in turn caused x86-32 boot failures, because the extra alignment
would result in random zero-filled words in the altinstructions section,
causing oopses early at boot when doing alternative instruction
replacement.
So just remove all the alignment noise entirely. It's wrong, and it's
unnecessary. The section itself is already properly aligned by the
linker scripts, and all additions to the section had better be of the
proper 12-byte format, keeping it aligned. So if the align directive
were to ever make a difference, that would be an indication of a serious
bug to begin with.
Reported-by: Werner Landgraf <w.landgraf@ru.r>
Acked-by: Andrew Lutomirski <luto@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not a good reason to allocate memory in the smp function call
just because someone thought it's the most conveniant place.
The AMD L3 data is coupled to the northbridge info by a pointer to the
corresponding north bridge data. So allocating it with the northbridge
data and referencing the northbridge in the cache_info code instead
uses less memory and gets rid of that atomic allocation hack in the
smp function call.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Hans Rosenfeld <hans.rosenfeld@amd.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Mike Travis <travis@sgi.com>
Link: http://lkml.kernel.org/r/20110723212626.688229918@linutronix.de
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit de2d1a524e ("KVM: Fix register corruption in pvclock_scale_delta")
introduced a mul instruction that may have only a memory operand; the
assembler therefore cannot select the correct size:
pvclock.s:229: Error: no instruction mnemonic suffix given and no register
operands; can't size instruction
In this example the assembler is:
#APP
mul -48(%rbp) ; shrd $32, %rdx, %rax
#NO_APP
A simple solution is to use mulq.
Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Avi Kivity <avi@redhat.com>
The inner loop of __ticket_spin_lock isn't doing anything very special,
so reimplement it in C.
For the 8 bit ticket lock variant, we use a register union to get direct
access to the lower and upper bytes in the tickets, but unfortunately gcc
won't generate a direct comparison between the two halves of the register,
so the generated asm isn't quite as pretty as the hand-coded version.
However benchmarking shows that this is actually a small improvement in
runtime performance on some benchmarks, and never a slowdown.
We also need to make sure there's a barrier at the end of the lock loop
to make sure that the compiler doesn't move any instructions from within
the locked region into the region where we don't yet own the lock.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
A few cleanups to the way spinlocks are defined and accessed:
- define __ticket_t which is the size of a spinlock ticket (ie, enough
bits to hold all the cpus)
- Define struct arch_spinlock as a union containing plain slock and
the head and tail tickets
- Use head and tail to implement some of the spinlock predicates.
- Make all ticket variables unsigned.
- Use TICKET_SHIFT to form constants
Most of this will be used in later patches.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The function hv_post_msg() can fail because of transient resource
conditions. It may be useful to retry the operation.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen/tracing: Fix tracing config option properly
xen: Do not enable PV IPIs when vector callback not present
xen/x86: replace order-based range checking of M2P table by linear one
xen: xen-selfballoon.c needs more header files
