CVE-2024-35980

protected during live migration. Unfortunately, the operand passed to the TLBI RANGE instruction isn't correctly sorted out due to the commit 117940aa6e5f ("KVM: arm64: Define kvm_tlb_flush_vmid_range()"). It leads to crash on the destination VM after live migration because TLBs aren't flushed completely and some of the dirty pages are missed. For example, I have a VM where 8GB memory is assigned, starting from 0x40000000 (1GB). Note that the host has 4KB as the base page size. In the middile of migration, kvm_tlb_flush_vmid_range() is executed to flush TLBs. It passes MAX_TLBI_RANGE_PAGES as the argument to __kvm_tlb_flush_vmid_range() and __flush_s2_tlb_range_op(). SCALE#3 and NUM#31, corresponding to MAX_TLBI_RANGE_PAGES, isn't supported by __TLBI_RANGE_NUM(). In this specific case, -1 has been returned from __TLBI_RANGE_NUM() for SCALE#3/2/1/0 and rejected by the loop in the __flush_tlb_range_op() until the variable @scale underflows and becomes -9, 0xffff708000040000 is set as the operand. The operand is wrong since it's sorted out by __TLBI_VADDR_RANGE() according to invalid @scale and @num. Fix it by extending __TLBI_RANGE_NUM() to support the combination of SCALE#3 and NUM#31. With the changes, [-1 31] instead of [-1 30] can be returned from the macro, meaning the TLBs for 0x200000 pages in the above example can be flushed in one shoot with SCALE#3 and NUM#31. The macro TLBI_RANGE_MASK is dropped since no one uses it any more. The comments are also adjusted accordingly.