On 3/21/22 23:43, Ben Gardon wrote:
Currently disabling dirty logging with the TDP MMU is extremely slow. On a 96 vCPU / 96G VM it takes ~256 seconds to disable dirty logging with the TDP MMU, as opposed to ~4 seconds with the legacy MMU. This series optimizes TLB flushes and introduces in-place large page promotion, to bring the disable dirty log time down to ~3 seconds. Testing: Ran KVM selftests and kvm-unit-tests on an Intel Haswell. This series introduced no new failures.
Thanks, looks good. The one change I'd make is to just place the outcome of build_tdp_shadow_zero_bits_mask() in a global (say tdp_shadow_zero_check) at kvm_configure_mmu() time. The tdp_max_root_level works as a conservative choice for the second argument of build_tdp_shadow_zero_bits_mask().
No need to do anything though, I'll handle this later in 5.19 time (and first merge my changes that factor out the constant part of vcpu->arch.root_mmu initialization, since this is part of the same ideas).
Paolo
