linux/arch/x86
Luiz Capitulino 4f5758fc67 kvm: x86: export TSC information to user-space
This commit exports the following information to
user-space via the newly created per-vcpu debugfs
directory:

 - TSC offset (as a signed number)
 - TSC scaling ratio
 - TSC scaling ratio fractinal bits

The original intention of this commit was to
export only the TSC offset, but the TSC scaling
information is exported for completeness.

We need to retrieve the TSC offset from user-space
in order to support the merging of host and guest
traces in trace-cmd. Today, we use the kvm_write_tsc_offset
tracepoint, but it has a number of problems (mainly,
it requires a running VM to be rebooted, ftrace setup,
and also tracepoints are not supposed to be ABIs).

The merging of host and guest traces is explained
in more detail in this thread:

 [Qemu-devel] [RFC] host and guest kernel trace merging
 https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg00887.html

This commit creates the following files in debugfs:

/sys/kernel/debug/kvm/66828-10/vcpu0/tsc-offset
/sys/kernel/debug/kvm/66828-10/vcpu0/tsc-scaling-ratio
/sys/kernel/debug/kvm/66828-10/vcpu0/tsc-scaling-ratio-frac-bits

The last two are only created if TSC scaling is supported.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-16 16:57:48 +02:00
..
boot Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:37:12 -04:00
configs arch/defconfig: remove CONFIG_RESOURCE_COUNTERS 2016-05-23 17:04:14 -07:00
crypto x86, crypto: Restore MODULE_LICENSE() to glue_helper.c so it loads 2016-07-20 09:39:50 +02:00
entry x86/build: Reduce the W=1 warnings noise when compiling x86 syscall tables 2016-08-10 16:05:16 +02:00
events perf/x86/intel/uncore: Add enable_box for client MSR uncore 2016-08-12 08:35:05 +02:00
ia32 mm: remove more IS_ERR_VALUE abuses 2016-05-27 15:57:31 -07:00
include kvm: x86: drop read_tsc_offset() 2016-09-16 16:57:45 +02:00
kernel x86/smp: Fix __max_logical_packages value setup 2016-08-18 10:14:48 +02:00
kvm kvm: x86: export TSC information to user-space 2016-09-16 16:57:48 +02:00
lguest lguest: Read offset of device_cap later 2016-06-10 11:39:09 +02:00
lib x86/mm/kaslr: Fix -Wformat-security warning 2016-08-11 10:58:12 +02:00
math-emu
mm Power management fixes for v4.8-rc2 2016-08-12 16:23:58 -07:00
net bpf, x86: add support for constant blinding 2016-05-16 13:49:32 -04:00
oprofile x86/cpufeature: Replace cpu_has_apic with boot_cpu_has() usage 2016-04-13 11:37:41 +02:00
pci dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
platform Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-08-12 14:31:10 -07:00
power x86/power/64: Use __pa() for physical address computation 2016-08-16 00:39:37 +02:00
purgatory Add sancov plugin 2016-06-07 22:57:10 +02:00
ras x86/RAS/AMD: Reduce the number of IPIs when prepping error injection 2016-07-08 11:29:26 +02:00
realmode x86/boot: Rework reserve_real_mode() to allow multiple tries 2016-08-11 11:15:01 +02:00
tools x86/insn: Add AVX-512 support to the instruction decoder 2016-07-21 09:37:11 -03:00
um Merge branch 'for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2016-08-04 19:37:59 -04:00
video x86/video: Don't assume all FB devices are PCI devices 2016-03-15 11:08:26 +01:00
xen kexec: allow kdump with crash_kexec_post_notifiers 2016-08-02 19:35:30 -04:00
.gitignore
Kbuild
Kconfig Implements HARDENED_USERCOPY verification of copy_to_user/copy_from_user 2016-08-08 14:48:14 -07:00
Kconfig.cpu
Kconfig.debug Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-15 09:32:27 -07:00
Makefile kbuild: abort build on bad stack protector flag 2016-07-26 16:19:19 -07:00
Makefile_32.cpu
Makefile.um