On Fri, Sep 25, 2020 at 02:22:53PM -0700, Ben Gardon wrote: > In order to interoperate correctly with the rest of KVM and other Linux > subsystems, the TDP MMU must correctly handle various MMU notifiers. Add > hooks to handle the invalidate range family of MMU notifiers. > > Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell > machine. This series introduced no new failures. > > This series can be viewed in Gerrit at: > https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538 > > Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx> > --- > arch/x86/kvm/mmu/mmu.c | 9 ++++- > arch/x86/kvm/mmu/tdp_mmu.c | 80 +++++++++++++++++++++++++++++++++++--- > arch/x86/kvm/mmu/tdp_mmu.h | 3 ++ > 3 files changed, 86 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 52d661a758585..0ddfdab942554 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -1884,7 +1884,14 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, > int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, > unsigned flags) > { > - return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); > + int r; > + > + r = kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); > + > + if (kvm->arch.tdp_mmu_enabled) > + r |= kvm_tdp_mmu_zap_hva_range(kvm, start, end); Similar to an earlier question, is this intentionally additive, or can this instead by: if (kvm->arch.tdp_mmu_enabled) r = kvm_tdp_mmu_zap_hva_range(kvm, start, end); else r = kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); > + > + return r; > } > > int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index 557e780bdf9f9..1cea58db78a13 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -60,7 +60,7 @@ bool is_tdp_mmu_root(struct kvm *kvm, hpa_t hpa) > } > > static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, > - gfn_t start, gfn_t end); > + gfn_t start, gfn_t end, bool can_yield); > > static void free_tdp_mmu_root(struct kvm *kvm, struct kvm_mmu_page *root) > { > @@ -73,7 +73,7 @@ static void free_tdp_mmu_root(struct kvm *kvm, struct kvm_mmu_page *root) > > list_del(&root->link); > > - zap_gfn_range(kvm, root, 0, max_gfn); > + zap_gfn_range(kvm, root, 0, max_gfn, false); > > free_page((unsigned long)root->spt); > kmem_cache_free(mmu_page_header_cache, root); > @@ -361,9 +361,14 @@ static bool tdp_mmu_iter_cond_resched(struct kvm *kvm, struct tdp_iter *iter) > * non-root pages mapping GFNs strictly within that range. Returns true if > * SPTEs have been cleared and a TLB flush is needed before releasing the > * MMU lock. > + * If can_yield is true, will release the MMU lock and reschedule if the > + * scheduler needs the CPU or there is contention on the MMU lock. If this > + * function cannot yield, it will not release the MMU lock or reschedule and > + * the caller must ensure it does not supply too large a GFN range, or the > + * operation can cause a soft lockup. > */ > static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, > - gfn_t start, gfn_t end) > + gfn_t start, gfn_t end, bool can_yield) > { > struct tdp_iter iter; > bool flush_needed = false; > @@ -387,7 +392,10 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, > handle_changed_spte(kvm, as_id, iter.gfn, iter.old_spte, 0, > iter.level); > > - flush_needed = !tdp_mmu_iter_cond_resched(kvm, &iter); > + if (can_yield) > + flush_needed = !tdp_mmu_iter_cond_resched(kvm, &iter); flush_needed = !can_yield || !tdp_mmu_iter_cond_resched(kvm, &iter); > + else > + flush_needed = true; > } > return flush_needed; > } > @@ -410,7 +418,7 @@ bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start, gfn_t end) > */ > get_tdp_mmu_root(kvm, root); > > - flush = zap_gfn_range(kvm, root, start, end) || flush; > + flush = zap_gfn_range(kvm, root, start, end, true) || flush; > > put_tdp_mmu_root(kvm, root); > } > @@ -551,3 +559,65 @@ int kvm_tdp_mmu_page_fault(struct kvm_vcpu *vcpu, int write, int map_writable, > > return ret; > } > + > +static int kvm_tdp_mmu_handle_hva_range(struct kvm *kvm, unsigned long start, > + unsigned long end, unsigned long data, > + int (*handler)(struct kvm *kvm, struct kvm_memory_slot *slot, > + struct kvm_mmu_page *root, gfn_t start, > + gfn_t end, unsigned long data)) > +{ > + struct kvm_memslots *slots; > + struct kvm_memory_slot *memslot; > + struct kvm_mmu_page *root; > + int ret = 0; > + int as_id; > + > + for_each_tdp_mmu_root(kvm, root) { > + /* > + * Take a reference on the root so that it cannot be freed if > + * this thread releases the MMU lock and yields in this loop. > + */ > + get_tdp_mmu_root(kvm, root); > + > + as_id = kvm_mmu_page_as_id(root); > + slots = __kvm_memslots(kvm, as_id); > + kvm_for_each_memslot(memslot, slots) { > + unsigned long hva_start, hva_end; > + gfn_t gfn_start, 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_start, gfn_start+1, ..., gfn_end-1}. > + */ > + gfn_start = hva_to_gfn_memslot(hva_start, memslot); > + gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot); > + > + ret |= handler(kvm, memslot, root, gfn_start, > + gfn_end, data); Eh, I'd say let this one poke out, the above hva_to_gfn_memslot() already overruns 80 chars. IMO it's more readable without the wraps. > + } > + > + put_tdp_mmu_root(kvm, root); > + } > + > + return ret; > +} > + > +static int zap_gfn_range_hva_wrapper(struct kvm *kvm, > + struct kvm_memory_slot *slot, > + struct kvm_mmu_page *root, gfn_t start, > + gfn_t end, unsigned long unused) > +{ > + return zap_gfn_range(kvm, root, start, end, false); > +} > + > +int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start, > + unsigned long end) > +{ > + return kvm_tdp_mmu_handle_hva_range(kvm, start, end, 0, > + zap_gfn_range_hva_wrapper); > +} > diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h > index abf23dc0ab7ad..ce804a97bfa1d 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.h > +++ b/arch/x86/kvm/mmu/tdp_mmu.h > @@ -18,4 +18,7 @@ void kvm_tdp_mmu_zap_all(struct kvm *kvm); > int kvm_tdp_mmu_page_fault(struct kvm_vcpu *vcpu, int write, int map_writable, > int level, gpa_t gpa, kvm_pfn_t pfn, bool prefault, > bool lpage_disallowed); > + > +int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start, > + unsigned long end); > #endif /* __KVM_X86_MMU_TDP_MMU_H */ > -- > 2.28.0.709.gb0816b6eb0-goog >
