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Subject[PATCH v2 0/6] kvm: x86: export TSC information to user-space
Date
[Introduction will follow]

Changelog
---------

v2

- add tsc_offset field to struct kvm_vcpu_arch
- drop read_tsc_offset()
- add per-vcpu dir entries in debugfs
- export TSC scaling info (besides TSC offset)
- export the TSC offset as a signed number
- drop patch that wrongly tried to improve error
handling in kvm_create_vm_debugfs()

Intro
-----

This series exports a VM's TSC offset and TSC scaling
information to user-space via a new per-vcpu directory
in debugfs. For example:

/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 TSC offset in particular is needed in user-space
in order for tracing tools, such as trace-cmd, to be
able to merge the host and guest traces using the
host TSC. This is explained in 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

Luiz Capitulino (6):
kvm: x86: add tsc_offset field to struct kvm_vcpu_arch
kvm: x86: drop read_tsc_offset()
kvm: kvm_destroy_vm_debugfs(): check debugfs_stat_data pointer
kvm: add stubs for arch specific debugfs support
kvm: create per-vcpu dirs in debugfs
kvm: x86: export TSC information to user-space

arch/arm/kvm/arm.c | 10 ++++++
arch/mips/kvm/mips.c | 10 ++++++
arch/powerpc/kvm/powerpc.c | 10 ++++++
arch/s390/kvm/kvm-s390.c | 10 ++++++
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/Makefile | 2 +-
arch/x86/kvm/debugfs.c | 69 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/svm.c | 8 -----
arch/x86/kvm/vmx.c | 6 ----
arch/x86/kvm/x86.c | 12 +++++--
include/linux/kvm_host.h | 4 +++
virt/kvm/kvm_main.c | 40 ++++++++++++++++++++++--
12 files changed, 161 insertions(+), 22 deletions(-)
create mode 100644 arch/x86/kvm/debugfs.c

--
2.5.5

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