[PATCH 0/7] KVM: x86: Tracepoint improvements and fixes

Sean Christopherson
2020-07-18T06:39:40Z

Various improvements and fixes for the kvm_entry, kvm_exit and
kvm_nested_vmexit tracepoints.

1. Capture the guest's RIP during kvm_entry for obvious reasons.

2. Extend kvm_exit to report the same info as kvm_nested_vmexit, and
macrofy its definition to reuse it verbatim for nested exits.

3. Stop passing in params to kvm_nested_vmexit, and instead use the
same approach (and now code) as kvm_exit where the tracepoint uses a
dedicated kvm_x86_ops hook to retrieve the info.

4. Stop reading GUEST_RIP, EXIT_QUAL, INTR_INFO, and ERROR_CODE on
every VM-Exit from L2 (some of this comes in #3). This saves ~100
cycles (150+ with retpolines) on VM-Exits from L2 that are handled
by L0, e.g. hardware interrupts.

Sean Christopherson (7):
KVM: x86: Add RIP to the kvm_entry, i.e. VM-Enter, tracepoint
KVM: x86: Read guest RIP from within the kvm_nested_vmexit tracepoint
KVM: VMX: Add a helper to test for a valid error code given an intr
info
KVM: x86: Add intr/vectoring info and error code to kvm_exit
tracepoint
KVM: x86: Add macro wrapper for defining kvm_exit tracepoint
KVM: x86: Use common definition for kvm_nested_vmexit tracepoint
KVM: nVMX: Read EXIT_QUAL and INTR_INFO only when needed for nested
exit

arch/x86/include/asm/kvm_host.h | 7 ++-
arch/x86/kvm/svm/svm.c | 16 ++---
arch/x86/kvm/trace.h | 107 +++++++++++++-------------------
arch/x86/kvm/vmx/nested.c | 14 ++---
arch/x86/kvm/vmx/vmcs.h | 7 +++
arch/x86/kvm/vmx/vmx.c | 18 +++++-
arch/x86/kvm/x86.c | 2 +-
7 files changed, 86 insertions(+), 85 deletions(-)

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2.26.0