GIC v4.1 introduced changes to the GIC CPU interface; systems that integrate CPUs that do not support GIC v4.1 features (as reported in the ID_AA64PFR0_EL1.GIC bitfield) and a GIC v4.1 controller must disable in software virtual SGIs support since the CPUIF and GIC controller version mismatch results in CONSTRAINED UNPREDICTABLE behaviour at architectural level.
For systems with CPUs reporting ID_AA64PFR0_EL1.GIC == b0001 integrated in a system with a GIC v4.1 it _should_ still be safe to enable vLPIs (other than vSGI) since the protocol between the GIC redistributor and the GIC CPUIF was not changed from GIC v4.0 to GIC v4.1. Cc: Will Deacon <w...@kernel.org> Cc: Catalin Marinas <catalin.mari...@arm.com> Cc: Marc Zyngier <m...@kernel.org> Lorenzo Pieralisi (2): arm64: cpufeature: Add GIC CPUIF v4.1 detection irqchip/gic-v3-its: Disable vSGI upon (CPUIF < v4.1) detection arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/kernel/cpufeature.c | 10 ++++++++++ drivers/irqchip/irq-gic-v3-its.c | 20 +++++++++++++++++++- 3 files changed, 31 insertions(+), 2 deletions(-) -- 2.29.1
