Invalidate gfn_to_pfn_caches when the memory attributes of the gfn it contains change.
Since gfn_to_pfn_caches are not hooked up to KVM's MMU notifiers, but rather have to be invalidated right _before_ KVM's MMU notifiers are triggers, adopt the approach used by kvm_mmu_notifier_invalidate_range_start for invalidating gpcs inside kvm_vm_set_mem_attributes. Signed-off-by: Patrick Roy <[email protected]> --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 5 +++++ virt/kvm/kvm_mm.h | 10 +++++++++ virt/kvm/pfncache.c | 45 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 61 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index cd28eb34aaeb1..7d36164a2cee5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -840,6 +840,7 @@ struct kvm { #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES /* Protected by slots_locks (for writes) and RCU (for reads) */ struct xarray mem_attr_array; + bool attribute_change_in_progress; #endif char stats_id[KVM_STATS_NAME_SIZE]; }; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 13347fb03d4a9..183f7ce57a428 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2533,6 +2533,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, mutex_lock(&kvm->slots_lock); + /* Nothing to do if the entire range as the desired attributes. */ if (kvm_range_has_memory_attributes(kvm, start, end, attributes)) goto out_unlock; @@ -2547,6 +2548,9 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, goto out_unlock; } + kvm->attribute_change_in_progress = true; + gfn_to_pfn_cache_invalidate_gfns_start(kvm, start, end); + kvm_handle_gfn_range(kvm, &pre_set_range); for (i = start; i < end; i++) { @@ -2558,6 +2562,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, kvm_handle_gfn_range(kvm, &post_set_range); out_unlock: + kvm->attribute_change_in_progress = false; mutex_unlock(&kvm->slots_lock); return r; diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h index 715f19669d01f..5a53d888e4b18 100644 --- a/virt/kvm/kvm_mm.h +++ b/virt/kvm/kvm_mm.h @@ -27,12 +27,22 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible, void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, unsigned long start, unsigned long end); + +void gfn_to_pfn_cache_invalidate_gfns_start(struct kvm *kvm, + gfn_t start, + gfn_t end); #else static inline void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, unsigned long start, unsigned long end) { } + +static inline void gfn_to_pfn_cache_invalidate_gfns_start(struct kvm *kvm, + gfn_t start, + gfn_t end) +{ +} #endif /* HAVE_KVM_PFNCACHE */ #ifdef CONFIG_KVM_PRIVATE_MEM diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index f0039efb9e1e3..6de934a8a153f 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -57,6 +57,43 @@ void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, unsigned long start, spin_unlock(&kvm->gpc_lock); } +/* + * Identical to `gfn_to_pfn_cache_invalidate_start`, except based on gfns + * instead of uhvas. + */ +void gfn_to_pfn_cache_invalidate_gfns_start(struct kvm *kvm, gfn_t start, gfn_t end) +{ + struct gfn_to_pfn_cache *gpc; + + spin_lock(&kvm->gpc_lock); + list_for_each_entry(gpc, &kvm->gpc_list, list) { + read_lock_irq(&gpc->lock); + + /* + * uhva based gpcs must not be used with gmem enabled memslots + */ + if (kvm_is_error_gpa(gpc->gpa)) { + read_unlock_irq(&gpc->lock); + continue; + } + + if (gpc->valid && !is_error_noslot_pfn(gpc->pfn) && + gpa_to_gfn(gpc->gpa) >= start && gpa_to_gfn(gpc->gpa) < end) { + read_unlock_irq(&gpc->lock); + + write_lock_irq(&gpc->lock); + if (gpc->valid && !is_error_noslot_pfn(gpc->pfn) && + gpa_to_gfn(gpc->gpa) >= start && gpa_to_gfn(gpc->gpa) < end) + gpc->valid = false; + write_unlock_irq(&gpc->lock); + continue; + } + + read_unlock_irq(&gpc->lock); + } + spin_unlock(&kvm->gpc_lock); +} + static bool kvm_gpc_is_valid_len(gpa_t gpa, unsigned long uhva, unsigned long len) { @@ -141,6 +178,14 @@ static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_s if (kvm->mn_active_invalidate_count) return true; + /* + * Similarly to the above, attribute_change_in_progress is set + * before gfn_to_pfn_cache_invalidate_start is called in + * kvm_vm_set_mem_attributes, and isn't cleared until after + * mmu_invalidate_seq is updated. + */ + if (kvm->attribute_change_in_progress) + return true; /* * Ensure mn_active_invalidate_count is read before * mmu_invalidate_seq. This pairs with the smp_wmb() in -- 2.46.0
