[PATCH 0/5] KVM: arm64: Miscellaneous improvements

Alexandru Elisei alexandru.elisei at arm.com
Tue Dec 1 10:01:52 EST 2020

The documentation update in the first patch was suggested by Marc [1]. When
I was going through the code to track down all the places error codes were
coming from I noticed a few things that in my opinion could be improved.
The following patches aim to do just that. I'm fine dropping them if the
churn looks unjustified.

Tested the Documentation changes by building pdfdocs, didn't notice any
warnings regarding api.rst.

Tested the other patches on a rockpro64 on the little cores. I ran
kvm-unit-tests with qemu and kvmtool. I also ran a Linux guest with qemu
and ran perf:

$ perf record -a -- iperf3 -c -t 60

I checked that interrupts were firing and nothing looked out of the
ordinary. I used qemu because qemu VCPUs do initialization concurrently
from their own thread, not from the main thread like kvmtool.

To check that kvm_timer_enable() is never reached if the VGIC is not
initialized, I hacked kvmtool to remove the ioctl
When trying to run a guest, I got the following error message:

KVM_RUN failed: Device or resource busy

which is consistent with the EBUSY return code from
vgic_v3_map_resources(). Double checked that that's where the code is
coming from by adding a pr_info statement to

[1] https://www.spinics.net/lists/arm-kernel/msg858024.html

Alexandru Elisei (5):
  KVM: Documentation: Add arm64 KVM_RUN error codes
  KVM: arm64: arch_timer: Remove VGIC initialization check
  KVM: arm64: Move double-checked lock to kvm_vgic_map_resources()
  KVM: arm64: Update comment in kvm_vgic_map_resources()
  KVM: arm64: Remove redundant call to kvm_pmu_vcpu_reset()

 Documentation/virt/kvm/api.rst  | 9 +++++++--
 arch/arm64/kvm/arch_timer.c     | 3 ---
 arch/arm64/kvm/arm.c            | 8 +++-----
 arch/arm64/kvm/pmu-emul.c       | 2 --
 arch/arm64/kvm/vgic/vgic-init.c | 9 ++++++++-
 arch/arm64/kvm/vgic/vgic-v2.c   | 3 ---
 arch/arm64/kvm/vgic/vgic-v3.c   | 3 ---
 7 files changed, 18 insertions(+), 19 deletions(-)


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