CVE-2026-89907LoongArch: KVM: Validate MSI data before routing it to EIOINTC

Official description

In the Linux kernel, the following vulnerability has been resolved: LoongArch: KVM: Validate MSI data before routing it to EIOINTC pch_msi_set_irq() passes e->msi.data straight into eiointc_set_irq() as the irq number. The MSI data comes from userspace, that either via a KVM_IRQ_ROUTING_MSI entry set with KVM_SET_GSI_ROUTING (used by irqfd and KVM_IRQ_LINE) or directly via KVM_SIGNAL_MSI, and is never checked against EIOINTC_IRQS. eiointc_set_irq() uses the value with __set_bit()/__clear_bit() on the 256-bit isr bitmap, eiointc_update_irq() then indexes sw_coremap[] and the per-cpu coreisr/sw_coreisr bitmaps with it. Therefore a data value >= 256 reads and writes memory past the end of those arrays, i.e. any process holding a VM fd can corrupt kernel memory beyond the allocation of loongarch_eiointc. Reject MSI data that doesn't fit in the EIOINTC irq space. The DMSINTC path is unaffected as it decodes the vector from the address and masks it.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/506f03b5f869cbae50d31b50d80d4a5735d47f94
• https://git.kernel.org/stable/c/83715a40a2d30d23719e0b25380ba82ff905195b
• https://git.kernel.org/stable/c/501514d6ebd2111c353a1296f25dbe22fbd64657