Re: [PATCH v3 3/5] KVM: arm64: Add PMU event filtering infrastructure
From: Andrew Jones <hidden>
Date: 2020-09-08 10:17:19
Also in:
kvm, kvmarm
On Tue, Sep 08, 2020 at 08:58:28AM +0100, Marc Zyngier wrote:
It can be desirable to expose a PMU to a guest, and yet not want the guest to be able to count some of the implemented events (because this would give information on shared resources, for example. For this, let's extend the PMUv3 device API, and offer a way to setup a bitmap of the allowed events (the default being no bitmap, and thus no filtering). Userspace can thus allow/deny ranges of event. The default policy depends on the "polarity" of the first filter setup (default deny if the filter allows events, and default allow if the filter denies events). This allows to setup exactly what is allowed for a given guest. Note that although the ioctl is per-vcpu, the map of allowed events is global to the VM (it can be setup from any vcpu until the vcpu PMU is initialized). Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/include/asm/kvm_host.h | 5 +++ arch/arm64/include/uapi/asm/kvm.h | 16 +++++++ arch/arm64/kvm/arm.c | 2 + arch/arm64/kvm/pmu-emul.c | 70 ++++++++++++++++++++++++++++--- 4 files changed, 87 insertions(+), 6 deletions(-)
Reviewed-by: Andrew Jones <redacted> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel