Commit Graph

33 Commits

Author SHA1 Message Date
Yoshihiro YUNOMAE 489223edf2 kvm: Add a tracepoint write_tsc_offset
Add a tracepoint write_tsc_offset for tracing TSC offset change.
We want to merge ftrace's trace data of guest OSs and the host OS using
TSC for timestamp in chronological order. We need "TSC offset" values for
each guest when merge those because the TSC value on a guest is always the
host TSC plus guest's TSC offset. If we get the TSC offset values, we can
calculate the host TSC value for each guest events from the TSC offset and
the event TSC value. The host TSC values of the guest events are used when we
want to merge trace data of guests and the host in chronological order.
(Note: the trace_clock of both the host and the guest must be set x86-tsc in
this case)

This tracepoint also records vcpu_id which can be used to merge trace data for
SMP guests. A merge tool will read TSC offset for each vcpu, then the tool
converts guest TSC values to host TSC values for each vcpu.

TSC offset is stored in the VMCS by vmx_write_tsc_offset() or
vmx_adjust_tsc_offset(). KVM executes the former function when a guest boots.
The latter function is executed when kvm clock is updated. Only host can read
TSC offset value from VMCS, so a host needs to output TSC offset value
when TSC offset is changed.

Since the TSC offset is not often changed, it could be overwritten by other
frequent events while tracing. To avoid that, I recommend to use a special
instance for getting this event:

1. set a instance before booting a guest
 # cd /sys/kernel/debug/tracing/instances
 # mkdir tsc_offset
 # cd tsc_offset
 # echo x86-tsc > trace_clock
 # echo 1 > events/kvm/kvm_write_tsc_offset/enable

2. boot a guest

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-06-27 14:20:51 +03:00
Marcelo Tosatti b48aa97e38 KVM: x86: require matched TSC offsets for master clock
With master clock, a pvclock clock read calculates:

ret = system_timestamp + [ (rdtsc + tsc_offset) - tsc_timestamp ]

Where 'rdtsc' is the host TSC.

system_timestamp and tsc_timestamp are unique, one tuple
per VM: the "master clock".

Given a host with synchronized TSCs, its obvious that
guest TSC must be matched for the above to guarantee monotonicity.

Allow master clock usage only if guest TSCs are synchronized.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-11-27 23:29:15 -02:00
Marcelo Tosatti d828199e84 KVM: x86: implement PVCLOCK_TSC_STABLE_BIT pvclock flag
KVM added a global variable to guarantee monotonicity in the guest.
One of the reasons for that is that the time between

	1. ktime_get_ts(&timespec);
	2. rdtscll(tsc);

Is variable. That is, given a host with stable TSC, suppose that
two VCPUs read the same time via ktime_get_ts() above.

The time required to execute 2. is not the same on those two instances
executing in different VCPUS (cache misses, interrupts...).

If the TSC value that is used by the host to interpolate when
calculating the monotonic time is the same value used to calculate
the tsc_timestamp value stored in the pvclock data structure, and
a single <system_timestamp, tsc_timestamp> tuple is visible to all
vcpus simultaneously, this problem disappears. See comment on top
of pvclock_update_vm_gtod_copy for details.

Monotonicity is then guaranteed by synchronicity of the host TSCs
and guest TSCs.

Set TSC stable pvclock flag in that case, allowing the guest to read
clock from userspace.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-11-27 23:29:13 -02:00
Xiao Guangrong 26bf264e87 KVM: x86: Export svm/vmx exit code and vector code to userspace
Exporting KVM exit information to userspace to be consumed by perf.

Signed-off-by: Dong Hao <haodong@linux.vnet.ibm.com>
[ Dong Hao <haodong@linux.vnet.ibm.com>: rebase it on acme's git tree ]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Runzhen Wang <runzhen@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1347870675-31495-2-git-send-email-haodong@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-09-21 12:48:09 -03:00
Linus Torvalds 5fecc9d8f5 KVM updates for the 3.6 merge window
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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
  ...
2012-07-24 12:01:20 -07:00
Namhyung Kim b102f1d0f1 tracing/kvm: Use __print_hex() for kvm_emulate_insn tracepoint
The kvm_emulate_insn tracepoint used __print_insn()
for printing its instructions. However it makes the
format of the event hard to parse as it reveals TP
internals.

Fortunately, kernel provides __print_hex for almost
same purpose, we can use it instead of open coding
it. The user-space can be changed to parse it later.

That means raw kernel tracing will not be affected
by this change:

 # cd /sys/kernel/debug/tracing/
 # cat events/kvm/kvm_emulate_insn/format
 name: kvm_emulate_insn
 ID: 29
 format:
	...
 print fmt: "%x:%llx:%s (%s)%s", REC->csbase, REC->rip, __print_hex(REC->insn, REC->len), \
 __print_symbolic(REC->flags, { 0, "real" }, { (1 << 0) | (1 << 1), "vm16" }, \
 { (1 << 0), "prot16" }, { (1 << 0) | (1 << 2), "prot32" }, { (1 << 0) | (1 << 3), "prot64" }), \
 REC->failed ? " failed" : ""

 # echo 1 > events/kvm/kvm_emulate_insn/enable
 # cat trace
 # tracer: nop
 #
 # entries-in-buffer/entries-written: 2183/2183   #P:12
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
         qemu-kvm-1782  [002] ...1   140.931636: kvm_emulate_insn: 0:c102fa25:89 10 (prot32)
         qemu-kvm-1781  [004] ...1   140.931637: kvm_emulate_insn: 0:c102fa25:89 10 (prot32)

Link: http://lkml.kernel.org/n/tip-wfw6y3b9ugtey8snaow9nmg5@git.kernel.org
Link: http://lkml.kernel.org/r/1340757701-10711-2-git-send-email-namhyung@kernel.org

Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: kvm@vger.kernel.org
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-28 13:52:15 -04:00
Michael S. Tsirkin ae7a2a3fb6 KVM: host side for eoi optimization
Implementation of PV EOI using shared memory.
This reduces the number of exits an interrupt
causes as much as by half.

The idea is simple: there's a bit, per APIC, in guest memory,
that tells the guest that it does not need EOI.
We set it before injecting an interrupt and clear
before injecting a nested one. Guest tests it using
a test and clear operation - this is necessary
so that host can detect interrupt nesting -
and if set, it can skip the EOI MSR.

There's a new MSR to set the address of said register
in guest memory. Otherwise not much changed:
- Guest EOI is not required
- Register is tested & ISR is automatically cleared on exit

For testing results see description of previous patch
'kvm_para: guest side for eoi avoidance'.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-06-25 12:40:55 +03:00
Stefan Hajnoczi 0d460ffc09 KVM: Use __print_symbolic() for vmexit tracepoints
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>
2011-09-25 19:17:59 +03:00
Stefan Hajnoczi e097e5ffd6 KVM: Record instruction set in all vmexit tracepoints
The kvm_exit tracepoint recently added the isa argument to aid decoding
exit_reason.  The semantics of exit_reason depend on the instruction set
(vmx or svm) and the isa argument allows traces to be analyzed on other
machines.

Add the isa argument to kvm_nested_vmexit and kvm_nested_vmexit_inject
so these tracepoints can also be self-describing.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:58 +03:00
Xiao Guangrong 4f0226482d KVM: MMU: trace mmio page fault
Add tracepoints to trace mmio page fault

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-07-24 11:50:41 +03:00
Avi Kivity 9dac77fa40 KVM: x86 emulator: fold decode_cache into x86_emulate_ctxt
This saves a lot of pointless casts x86_emulate_ctxt and decode_cache.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-07-12 13:16:09 +03:00
Avi Kivity 36dd9bb5ce KVM: x86 emulator: rename decode_cache::eip to _eip
The name eip conflicts with a field of the same name in x86_emulate_ctxt,
which we plan to fold decode_cache into.

The name _eip is unfortunate, but what's really needed is a refactoring
here, not a better name.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-07-12 13:16:09 +03:00
David Sharp d5bf2ff072 tracing: Fix event alignment: kvm:kvm_hv_hypercall
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: David Sharp <dhsharp@google.com>
LKML-Reference: <1291421609-14665-8-git-send-email-dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-03-10 10:34:24 -05:00
Avi Kivity 586f960796 KVM: Add instruction-set-specific exit qualifications to kvm_exit trace
The exit reason alone is insufficient to understand exactly why an exit
occured; add ISA-specific trace parameters for additional information.

Because fetching these parameters is expensive on vmx, and because these
parameters are fetched even if tracing is disabled, we fetch the
parameters via a callback instead of as traditional trace arguments.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-01-12 11:29:41 +02:00
Avi Kivity aa17911e3c KVM: Record instruction set in kvm_exit tracepoint
exit_reason's meaning depend on the instruction set; record it so a trace
taken on one machine can be interpreted on another.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-01-12 11:29:40 +02:00
Avi Kivity e46479f852 KVM: Trace emulated instructions
Log emulated instructions in ftrace, especially if they failed.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-05-17 12:17:35 +03:00
Avi Kivity 5c1c85d08d KVM: Trace exception injection
Often an exception can help point out where things start to go wrong.

Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:15:27 +03:00
Avi Kivity 5bfd8b5455 KVM: Move kvm_exit tracepoint rip reading inside tracepoint
Reading rip is expensive on vmx, so move it inside the tracepoint so we only
incur the cost if tracing is enabled.

Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:15:25 +03:00
Xiao Guangrong 2ed152afc7 KVM: cleanup kvm trace
This patch does:

 - no need call tracepoint_synchronize_unregister() when kvm module
   is unloaded since ftrace can handle it

 - cleanup ftrace's macro

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:15:22 +03:00
Joerg Roedel 2e554e8d67 KVM: SVM: Add kvm_nested_intercepts tracepoint
This patch adds a tracepoint to get information about the
most important intercept bitmasks from the nested vmcb.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-04-25 13:53:10 +03:00
Joerg Roedel 052ce6211c KVM: SVM: Remove newlines from nested trace points
The tracing infrastructure adds its own newlines. Remove
them from the trace point printk format strings.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-04-25 12:34:31 +03:00
Avi Kivity 59200273c4 KVM: Trace failed msr reads and writes
Record failed msrs reads and writes, and the fact that they failed as well.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-03-01 12:36:06 -03:00
Avi Kivity 6e7d152967 KVM: Fix msr trace
- data is 64 bits wide, not unsigned long
- rw is confusingly named

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-03-01 12:36:06 -03:00
Gleb Natapov 55cd8e5a4e KVM: Implement bare minimum of HYPER-V MSRs
Minimum HYPER-V implementation should have GUEST_OS_ID, HYPERCALL and
VP_INDEX MSRs.

[avi: fix build on i386]

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-03-01 12:35:57 -03:00
Joerg Roedel 532a46b989 KVM: SVM: Add tracepoint for skinit instruction
This patch adds a tracepoint for the event that the guest
executed the SKINIT instruction. This information is
important because SKINIT is an SVM extenstion not yet
implemented by nested SVM and we may need this information
for debugging hypervisors that do not yet run on nested SVM.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:16 +02:00
Joerg Roedel ec1ff79084 KVM: SVM: Add tracepoint for invlpga instruction
This patch adds a tracepoint for the event that the guest
executed the INVLPGA instruction.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:16 +02:00
Joerg Roedel 236649de33 KVM: SVM: Add tracepoint for #vmexit because intr pending
This patch adds a special tracepoint for the event that a
nested #vmexit is injected because kvm wants to inject an
interrupt into the guest.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:16 +02:00
Joerg Roedel 17897f3668 KVM: SVM: Add tracepoint for injected #vmexit
This patch adds a tracepoint for a nested #vmexit that gets
re-injected to the guest.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:15 +02:00
Joerg Roedel d8cabddf7e KVM: SVM: Add tracepoint for nested #vmexit
This patch adds a tracepoint for every #vmexit we get from a
nested guest.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:15 +02:00
Joerg Roedel 0ac406de8f KVM: SVM: Add tracepoint for nested vmrun
This patch adds a dedicated kvm tracepoint for a nested
vmrun.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:15 +02:00
Gleb Natapov 1000ff8d89 KVM: Add trace points in irqchip code
Add tracepoint in msi/ioapic/pic set_irq() functions,
in IPI sending and in the point where IRQ is placed into
apic's IRR.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:11 +03:00
Avi Kivity cb24772140 KVM: Trace apic registers using their symbolic names
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:07 +03:00
Marcelo Tosatti 229456fc34 KVM: convert custom marker based tracing to event traces
This allows use of the powerful ftrace infrastructure.

See Documentation/trace/ for usage information.

[avi, stephen: various build fixes]
[sheng: fix control register breakage]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:59 +03:00