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The page reference will be dropped in the memslot free >> path. >> >> Remove the enc_region structure definition and the code which did >> upfront pinning, as they are no longer needed in view of the demand >> pinning support. >> >> Leave svm_register_enc_region() and svm_unregister_enc_region() as stubs >> since qemu is dependent on this API. >> >> Signed-off-by: Nikunj A Dadhania >> --- >> arch/x86/kvm/svm/sev.c | 208 ++++++++++++++++------------------------- >> arch/x86/kvm/svm/svm.c | 1 + >> arch/x86/kvm/svm/svm.h | 3 +- >> 3 files changed, 81 insertions(+), 131 deletions(-) >> >> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c >> index d972ab4956d4..a962bed97a0b 100644 >> --- a/arch/x86/kvm/svm/sev.c >> +++ b/arch/x86/kvm/svm/sev.c >> @@ -66,14 +66,6 @@ static unsigned int nr_asids; >> static unsigned long *sev_asid_bitmap; >> static unsigned long *sev_reclaim_asid_bitmap; >> >> -struct enc_region { >> - struct list_head list; >> - unsigned long npages; >> - struct page **pages; >> - unsigned long uaddr; >> - unsigned long size; >> -}; >> - >> /* Called with the sev_bitmap_lock held, or on shutdown */ >> static int sev_flush_asids(int min_asid, int max_asid) >> { >> @@ -257,8 +249,6 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) >> if (ret) >> goto e_free; >> >> - INIT_LIST_HEAD(&sev->regions_list); >> - >> return 0; >> >> e_free: >> @@ -1637,8 +1627,6 @@ static void sev_migrate_from(struct kvm_sev_info *dst, >> src->handle = 0; >> src->pages_locked = 0; >> src->enc_context_owner = NULL; >> - >> - list_cut_before(&dst->regions_list, &src->regions_list, &src->regions_list); >> } >> >> static int sev_es_migrate_from(struct kvm *dst, struct kvm *src) >> @@ -1861,115 +1849,13 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp) >> int svm_register_enc_region(struct kvm *kvm, >> struct kvm_enc_region *range) >> { >> - struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; >> - struct enc_region *region; >> - int ret = 0; >> - >> - if (!sev_guest(kvm)) >> - return -ENOTTY; >> - >> - /* If kvm is mirroring encryption context it isn't responsible for it */ >> - if (is_mirroring_enc_context(kvm)) >> - return -EINVAL; >> - >> - if (range->addr > ULONG_MAX || range->size > ULONG_MAX) >> - return -EINVAL; >> - >> - region = kzalloc(sizeof(*region), GFP_KERNEL_ACCOUNT); >> - if (!region) >> - return -ENOMEM; >> - >> - mutex_lock(&kvm->lock); >> - region->pages = sev_pin_memory(kvm, range->addr, range->size, ®ion->npages, 1); >> - if (IS_ERR(region->pages)) { >> - ret = PTR_ERR(region->pages); >> - mutex_unlock(&kvm->lock); >> - goto e_free; >> - } >> - >> - region->uaddr = range->addr; >> - region->size = range->size; >> - >> - list_add_tail(®ion->list, &sev->regions_list); >> - mutex_unlock(&kvm->lock); >> - >> - /* >> - * The guest may change the memory encryption attribute from C=0 -> C=1 >> - * or vice versa for this memory range. Lets make sure caches are >> - * flushed to ensure that guest data gets written into memory with >> - * correct C-bit. >> - */ >> - sev_clflush_pages(region->pages, region->npages); >> - >> - return ret; >> - >> -e_free: >> - kfree(region); >> - return ret; >> -} >> - >> -static struct enc_region * >> -find_enc_region(struct kvm *kvm, struct kvm_enc_region *range) >> -{ >> - struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; >> - struct list_head *head = &sev->regions_list; >> - struct enc_region *i; >> - >> - list_for_each_entry(i, head, list) { >> - if (i->uaddr == range->addr && >> - i->size == range->size) >> - return i; >> - } >> - >> - return NULL; >> -} >> - >> -static void __unregister_enc_region_locked(struct kvm *kvm, >> - struct enc_region *region) >> -{ >> - sev_unpin_memory(kvm, region->pages, region->npages); >> - list_del(®ion->list); >> - kfree(region); >> + return 0; >> } >> >> int svm_unregister_enc_region(struct kvm *kvm, >> struct kvm_enc_region *range) >> { >> - struct enc_region *region; >> - int ret; >> - >> - /* If kvm is mirroring encryption context it isn't responsible for it */ >> - if (is_mirroring_enc_context(kvm)) >> - return -EINVAL; >> - >> - mutex_lock(&kvm->lock); >> - >> - if (!sev_guest(kvm)) { >> - ret = -ENOTTY; >> - goto failed; >> - } >> - >> - region = find_enc_region(kvm, range); >> - if (!region) { >> - ret = -EINVAL; >> - goto failed; >> - } >> - >> - /* >> - * Ensure that all guest tagged cache entries are flushed before >> - * releasing the pages back to the system for use. CLFLUSH will >> - * not do this, so issue a WBINVD. >> - */ >> - wbinvd_on_all_cpus(); >> - >> - __unregister_enc_region_locked(kvm, region); >> - >> - mutex_unlock(&kvm->lock); >> return 0; >> - >> -failed: >> - mutex_unlock(&kvm->lock); >> - return ret; >> } >> >> int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd) >> @@ -2018,7 +1904,6 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd) >> mirror_sev->fd = source_sev->fd; >> mirror_sev->es_active = source_sev->es_active; >> mirror_sev->handle = source_sev->handle; >> - INIT_LIST_HEAD(&mirror_sev->regions_list); >> ret = 0; >> >> /* >> @@ -2038,8 +1923,6 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd) >> void sev_vm_destroy(struct kvm *kvm) >> { >> struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; >> - struct list_head *head = &sev->regions_list; >> - struct list_head *pos, *q; >> >> WARN_ON(sev->num_mirrored_vms); >> >> @@ -2066,18 +1949,6 @@ void sev_vm_destroy(struct kvm *kvm) >> */ >> wbinvd_on_all_cpus(); >> >> - /* >> - * if userspace was terminated before unregistering the memory regions >> - * then lets unpin all the registered memory. >> - */ >> - if (!list_empty(head)) { >> - list_for_each_safe(pos, q, head) { >> - __unregister_enc_region_locked(kvm, >> - list_entry(pos, struct enc_region, list)); >> - cond_resched(); >> - } >> - } >> - >> sev_unbind_asid(kvm, sev->handle); >> sev_asid_free(sev); >> } >> @@ -2946,13 +2817,90 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector) >> ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, 1); >> } >> >> +void sev_pin_spte(struct kvm *kvm, gfn_t gfn, enum pg_level level, >> + kvm_pfn_t pfn) >> +{ >> + struct kvm_arch_memory_slot *aslot; >> + struct kvm_memory_slot *slot; >> + gfn_t rel_gfn, pin_pfn; >> + unsigned long npages; >> + kvm_pfn_t old_pfn; >> + int i; >> + >> + if (!sev_guest(kvm)) >> + return; >> + >> + if (WARN_ON_ONCE(is_error_noslot_pfn(pfn) || kvm_is_reserved_pfn(pfn))) >> + return; >> + >> + /* Tested till 1GB pages */ >> + if (KVM_BUG_ON(level > PG_LEVEL_1G, kvm)) >> + return; >> + >> + slot = gfn_to_memslot(kvm, gfn); >> + if (!slot || !slot->arch.pfns) >> + return; >> + >> + /* >> + * Use relative gfn index within the memslot for the bitmap as well as >> + * the pfns array >> + */ >> + rel_gfn = gfn - slot->base_gfn; >> + aslot = &slot->arch; >> + pin_pfn = pfn; >> + npages = KVM_PAGES_PER_HPAGE(level); >> + >> + /* Pin the page, KVM doesn't yet support page migration. */ >> + for (i = 0; i < npages; i++, rel_gfn++, pin_pfn++) { >> + if (test_bit(rel_gfn, aslot->pinned_bitmap)) { >> + old_pfn = aslot->pfns[rel_gfn]; >> + if (old_pfn == pin_pfn) >> + continue; >> + >> + put_page(pfn_to_page(old_pfn)); >> + } >> + >> + set_bit(rel_gfn, aslot->pinned_bitmap); >> + aslot->pfns[rel_gfn] = pin_pfn; >> + get_page(pfn_to_page(pin_pfn)); > > > I assume this is to replace KVM_MEMORY_ENCRYPT_REG_REGION, which ends up > calling svm_register_enc_region()->sev_pin_memory(), correct? Yes, that is correct. > > sev_pin_memory() correctly checks the RLIMIT_MEMLOCK and uses > pin_user_pages_fast(). > > I have to strongly assume that sev_pin_memory() is *wrong* as is because > it's supposed to supply FOLL_LONGTERM -- after all we're pinning these > pages possibly forever. > > > I might be wrong but > > 1. You are missing the RLIMIT_MEMLOCK check Yes, I will add this check during the enc_region registration. > 2. get_page() is the wong way of long-term pinning a page. You would > have to mimic what pin_user_pages_fast(FOLL_LONGTERM) does to eventually > get it right (e.g., migrate the page off of MIGRATE_CMA or ZONE_MOVABLE). Let me go through this and I will come back. Thanks for pointing this out. Regards Nikunj