Currently in arm_gicv3_icc_reset() we read the kernel's value of
ICC_CTLR_EL1 as part of resetting the CPU interface. This mostly
works, but we're actually breaking an assumption the kernel makes
that userspace only accesses the in-kernel GIC data when the VM is
totally paused, which may not be the case if a single vCPU is being
reset. The effect is that it's possible that the read attempt
returns EBUSY.
Avoid this by reading the kernel's value of the reset ICC_CTLR_EL1
once in device realize. This brings ICC_CTLR_EL1 into line with
the other cpuif registers, where we assume we know what the kernel
is resetting them to and just update QEMU's data structures in
arm_gicv3_icc_reset().
Reviewed-by: Salil Mehta <salil.mehta@huawei.com>
Tested-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20251014102439.319915-1-peter.maydell@linaro.org
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