On Tue, Apr 29, 2025 at 10:32:19PM +0000, Pranjal Shrivastava wrote: > On Fri, Apr 25, 2025 at 10:58:15PM -0700, Nicolin Chen wrote: > > To simplify the mappings from global VCMDQs to VINTFs' LVCMDQs, the design > > chose to do static allocations and mappings in the global reset function. > > > > However, with the user-owned VINTF support, it exposes a security concern: > > if user space VM only wants one LVCMDQ for a VINTF, statically mapping two > > LVCMDQs creates a hidden VCMDQ that user space could DoS attack by writing > > ramdon stuff to overwhelm the kernel with unhandleable IRQs. > > > > Nit: I think it's worth mentioning that the current HW only supports 2 > LVCMDQs. Since it's not clear from the driver as it calculates this by: > > regval = readl_relaxed(REG_CMDQV(cmdqv, PARAM)); > cmdqv->num_vintfs = 1 << FIELD_GET(CMDQV_NUM_VINTF_LOG2,regval); > cmdqv->num_vcmdqs = 1 << FIELD_GET(CMDQV_NUM_VCMDQ_LOG2, regval); > cmdqv->num_lvcmdqs_per_vintf = cmdqv->num_vcmdqs / cmdqv->num_vintfs; This is a SW choice. HW supports more LVCMDQs than 2 per VINTF. > Or maybe, re-word it to "if user space VM only wants one LVCMDQ for a > VINTF, the current driver statically maps num_lvcmdqs_per_vintf which > creates hidden vCMDQs [..]" But yea, this makes sense. Will change. Thanks Nicolin
