Hi,
This is a new version of the patchset to monitor guest TLB
operations. The user interface has been re-written to incorporate
feedback from LPC'16 on the previous version - it now uses a software
PMU instead of relying on perf trace to track guest TLB operations
(Patch 6 and 7). Previous versions of the patches can be found at
[0][1][2][3].
Guest TLB operations can impact on system performance but these are
not exported as architected PMU events on arm/arm64. Instead the
architecture allows trapping of TLB operations to the hypervisor. This
patchset builds on this feature to monitor TLB operations.
To minimise the performance impact, trapping is enabled -
* on user request
* for the VM of interest
With this patchset, running 'perf' on the host can be used to monitor
the TLB operations. E.g., to monitor a VM with process id 2589 -
# perf stat -a -C 0 -e kvm/kvm_tlb_invalidate,vm=2589/ sleep 25
Performance counter stats for 'system wide':
3,386 kvm/tlb_invalidate,vm=2589/
25.001086522 seconds time elapsed
The patches are based on v4.10-rc3 and have been tested on arm and
arm64.
Thanks,
Punit
[0] http://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1210715.html
[1] http://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1224353.html
[2] https://marc.info/?l=linux-kernel&m=147376184208258&w=2
[3] https://marc.info/?l=kvm&m=147750373716545&w=2
Changes:
v2 -> v3
* Replaced perf trace monitoring with software PMU
* Re-ordered patches as a result of the above re-write
v1 -> v2
* New (Patch 6) - Add support for trapping and emulating TLB
operations to ARM hosts
* Move common code to handle perf trace notifications to virt/kvm/arm
* Move tracepoint to include/trace/events/kvm.h
* Drop patch to introduce __tlbi helper as it is now merged
* Reorder patches
RFC v2 -> v1
* Dropped the RFC tag
* Patch 2 - Use VM thread group id for identification
* Patch 4 - Update comment for clarity
* Patch 6 - Add comment explaining switch to hype-role when VHE is enabled
* Patch 7 - Add comment to clarify struct kvm_trace_hook
RFC -> RFC v2
* Patch 4 - Rename left-over TLBI macro to __TLBI
* Patch 6 - Replace individual TLB operation emulation with
invalidating all stage 1 TLB for the VM. TLB monitoring is expected
to be a debug feature and performance is not critical.
Mark Rutland (1):
arm64/kvm: hyp: tlb: use __tlbi() helper
Punit Agrawal (8):
KVM: Track the pid of the VM process
KVM: Add event to trace tlb invalidations
arm: KVM: Handle trappable TLB instructions
arm64: KVM: Handle trappable TLB instructions
kvm: arm/arm64: Add host pmu to support VM introspection
kvm: host_pmu: Add support for tracking guest TLB operations
arm: KVM: Enable support for host pmu
arm64: KVM: Enable support for the host pmu
arch/arm/include/asm/kvm_asm.h | 2 +
arch/arm/include/asm/kvm_host.h | 9 ++
arch/arm/kvm/Kconfig | 4 +
arch/arm/kvm/Makefile | 1 +
arch/arm/kvm/arm.c | 2 +
arch/arm/kvm/coproc.c | 56 +++++++
arch/arm/kvm/hyp/tlb.c | 33 ++++
arch/arm64/include/asm/kvm_asm.h | 2 +
arch/arm64/include/asm/kvm_host.h | 9 ++
arch/arm64/kvm/Kconfig | 4 +
arch/arm64/kvm/Makefile | 1 +
arch/arm64/kvm/hyp/tlb.c | 87 +++++++++-
arch/arm64/kvm/sys_regs.c | 83 ++++++++++
include/linux/kvm_host.h | 1 +
include/trace/events/kvm.h | 18 +++
virt/kvm/arm/host_pmu.c | 322 ++++++++++++++++++++++++++++++++++++++
virt/kvm/kvm_main.c | 2 +
17 files changed, 630 insertions(+), 6 deletions(-)
create mode 100644 virt/kvm/arm/host_pmu.c
--
2.11.0
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