KVM lets userspace configure the IMSIC guest, HART, group-width, and group-shift fields independently. The individual bounds allow a layout such as guest_bits=7, hart_bits=6, group_bits=1, and group_shift=24. That layout places the group index bit at bit 24 while the lower guest+HART field also extends through bit 24. The IMSIC address helpers later consume these values as one address layout: aia_imsic_ppn() masks the lower guest+HART field and the group field, while aia_imsic_hart_index() combines the group and HART index. Allowing an overlapping configuration therefore gives one address bit two different meanings. Reject group-index layouts that start before the end of the guest+HART field before initializing the in-kernel irqchip. Fixes: 89d01306e34d ("RISC-V: KVM: Implement device interface for AIA irqchip") Signed-off-by: Pengpeng Hou --- arch/riscv/kvm/aia_device.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c index be83c2d5fc308..0793d4d4cf5e3 100644 --- a/arch/riscv/kvm/aia_device.c +++ b/arch/riscv/kvm/aia_device.c @@ -248,6 +248,12 @@ static int aia_init(struct kvm *kvm) if (aia->nr_sources && aia->aplic_addr == KVM_RISCV_AIA_UNDEF_ADDR) return -EINVAL; + /* Group index bits must not overlap guest and HART index bits. */ + if (aia->nr_group_bits && + aia->nr_group_shift < IMSIC_MMIO_PAGE_SHIFT + + aia->nr_guest_bits + aia->nr_hart_bits) + return -EINVAL; + /* Initialize APLIC */ ret = kvm_riscv_aia_aplic_init(kvm); if (ret) -- 2.43.0