From 491d6ecc17171518565358c2cfe33b59722d234c Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Fri, 20 Sep 2013 14:52:54 +1000 Subject: [PATCH] KVM: PPC: Book3S PR: Reduce number of shadow PTEs invalidated by MMU notifiers Currently, whenever any of the MMU notifier callbacks get called, we invalidate all the shadow PTEs. This is inefficient because it means that we typically then get a lot of DSIs and ISIs in the guest to fault the shadow PTEs back in. We do this even if the address range being notified doesn't correspond to guest memory. This commit adds code to scan the memslot array to find out what range(s) of guest physical addresses corresponds to the host virtual address range being affected. For each such range we flush only the shadow PTEs for the range, on all cpus. Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_pr.c | 40 ++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 2f84ed807184..6075dbd0b364 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -150,24 +150,48 @@ int kvmppc_core_check_requests(struct kvm_vcpu *vcpu) } /************* MMU Notifiers *************/ +static void do_kvm_unmap_hva(struct kvm *kvm, unsigned long start, + unsigned long end) +{ + long i; + struct kvm_vcpu *vcpu; + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + + slots = kvm_memslots(kvm); + kvm_for_each_memslot(memslot, slots) { + unsigned long hva_start, hva_end; + gfn_t gfn, gfn_end; + + hva_start = max(start, memslot->userspace_addr); + hva_end = min(end, memslot->userspace_addr + + (memslot->npages << PAGE_SHIFT)); + if (hva_start >= hva_end) + continue; + /* + * {gfn(page) | page intersects with [hva_start, hva_end)} = + * {gfn, gfn+1, ..., gfn_end-1}. + */ + gfn = hva_to_gfn_memslot(hva_start, memslot); + gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot); + kvm_for_each_vcpu(i, vcpu, kvm) + kvmppc_mmu_pte_pflush(vcpu, gfn << PAGE_SHIFT, + gfn_end << PAGE_SHIFT); + } +} int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) { trace_kvm_unmap_hva(hva); - /* - * Flush all shadow tlb entries everywhere. This is slow, but - * we are 100% sure that we catch the to be unmapped page - */ - kvm_flush_remote_tlbs(kvm); + do_kvm_unmap_hva(kvm, hva, hva + PAGE_SIZE); return 0; } int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) { - /* kvm_unmap_hva flushes everything anyways */ - kvm_unmap_hva(kvm, start); + do_kvm_unmap_hva(kvm, start, end); return 0; } @@ -187,7 +211,7 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva) void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) { /* The page will get remapped properly on its next fault */ - kvm_unmap_hva(kvm, hva); + do_kvm_unmap_hva(kvm, hva, hva + PAGE_SIZE); } /*****************************************/ -- 2.20.1