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| author | Marc Zyngier <maz@kernel.org> | 2022-01-27 16:17:54 +0000 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2022-02-08 17:51:21 +0000 |
| commit | 5177fe91e4cf78a659aada2c9cf712db4d788481 (patch) | |
| tree | 0a1bfbaf6d2aa6059fba04cb527b70fb048ab26a /Documentation | |
| parent | dfd42facf1e4ada021b939b4e19c935dcdd55566 (diff) | |
KVM: arm64: Do not change the PMU event filter after a VCPU has run
Userspace can specify which events a guest is allowed to use with the
KVM_ARM_VCPU_PMU_V3_FILTER attribute. The list of allowed events can be
identified by a guest from reading the PMCEID{0,1}_EL0 registers.
Changing the PMU event filter after a VCPU has run can cause reads of the
registers performed before the filter is changed to return different values
than reads performed with the new event filter in place. The architecture
defines the two registers as read-only, and this behaviour contradicts
that.
Keep track when the first VCPU has run and deny changes to the PMU event
filter to prevent this from happening.
Signed-off-by: Marc Zyngier <maz@kernel.org>
[ Alexandru E: Added commit message, updated ioctl documentation ]
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220127161759.53553-2-alexandru.elisei@arm.com
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virt/kvm/devices/vcpu.rst | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst index 60a29972d3f1..d063aaee5bb7 100644 --- a/Documentation/virt/kvm/devices/vcpu.rst +++ b/Documentation/virt/kvm/devices/vcpu.rst @@ -70,7 +70,7 @@ irqchip. -ENODEV PMUv3 not supported or GIC not initialized -ENXIO PMUv3 not properly configured or in-kernel irqchip not configured as required prior to calling this attribute - -EBUSY PMUv3 already initialized + -EBUSY PMUv3 already initialized or a VCPU has already run -EINVAL Invalid filter range ======= ====================================================== |