KVM: s390: CMMA tracking, ESSA emulation, migration mode
* Add a migration state bitmap to keep track of which pages have dirty CMMA information. * Disable CMMA by default, so we can track if it's used or not. Enable it on first use like we do for storage keys (unless we are doing a migration). * Creates a VM attribute to enter and leave migration mode. * In migration mode, CMMA is disabled in the SIE block, so ESSA is always interpreted and emulated in software. * Free the migration state on VM destroy. Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Claudio Imbrenda
committed by
Christian Borntraeger
Christian Borntraeger
szülő
865279c53c
commit
190df4a212
@@ -31,6 +31,7 @@
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#include <linux/bitmap.h>
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#include <linux/sched/signal.h>
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#include <linux/string.h>
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#include <asm/asm-offsets.h>
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#include <asm/lowcore.h>
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#include <asm/stp.h>
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@@ -750,6 +751,129 @@ static int kvm_s390_vm_set_crypto(struct kvm *kvm, struct kvm_device_attr *attr)
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return 0;
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}
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static void kvm_s390_sync_request_broadcast(struct kvm *kvm, int req)
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{
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int cx;
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struct kvm_vcpu *vcpu;
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kvm_for_each_vcpu(cx, vcpu, kvm)
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kvm_s390_sync_request(req, vcpu);
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}
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/*
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* Must be called with kvm->srcu held to avoid races on memslots, and with
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* kvm->lock to avoid races with ourselves and kvm_s390_vm_stop_migration.
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*/
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static int kvm_s390_vm_start_migration(struct kvm *kvm)
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{
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struct kvm_s390_migration_state *mgs;
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struct kvm_memory_slot *ms;
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/* should be the only one */
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struct kvm_memslots *slots;
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unsigned long ram_pages;
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int slotnr;
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/* migration mode already enabled */
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if (kvm->arch.migration_state)
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return 0;
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slots = kvm_memslots(kvm);
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if (!slots || !slots->used_slots)
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return -EINVAL;
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mgs = kzalloc(sizeof(*mgs), GFP_KERNEL);
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if (!mgs)
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return -ENOMEM;
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kvm->arch.migration_state = mgs;
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if (kvm->arch.use_cmma) {
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/*
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* Get the last slot. They should be sorted by base_gfn, so the
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* last slot is also the one at the end of the address space.
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* We have verified above that at least one slot is present.
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*/
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ms = slots->memslots + slots->used_slots - 1;
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/* round up so we only use full longs */
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ram_pages = roundup(ms->base_gfn + ms->npages, BITS_PER_LONG);
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/* allocate enough bytes to store all the bits */
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mgs->pgste_bitmap = vmalloc(ram_pages / 8);
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if (!mgs->pgste_bitmap) {
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kfree(mgs);
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kvm->arch.migration_state = NULL;
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return -ENOMEM;
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}
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mgs->bitmap_size = ram_pages;
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atomic64_set(&mgs->dirty_pages, ram_pages);
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/* mark all the pages in active slots as dirty */
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for (slotnr = 0; slotnr < slots->used_slots; slotnr++) {
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ms = slots->memslots + slotnr;
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bitmap_set(mgs->pgste_bitmap, ms->base_gfn, ms->npages);
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}
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kvm_s390_sync_request_broadcast(kvm, KVM_REQ_START_MIGRATION);
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}
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return 0;
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}
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/*
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* Must be called with kvm->lock to avoid races with ourselves and
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* kvm_s390_vm_start_migration.
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*/
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static int kvm_s390_vm_stop_migration(struct kvm *kvm)
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{
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struct kvm_s390_migration_state *mgs;
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/* migration mode already disabled */
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if (!kvm->arch.migration_state)
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return 0;
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mgs = kvm->arch.migration_state;
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kvm->arch.migration_state = NULL;
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if (kvm->arch.use_cmma) {
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kvm_s390_sync_request_broadcast(kvm, KVM_REQ_STOP_MIGRATION);
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vfree(mgs->pgste_bitmap);
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}
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kfree(mgs);
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return 0;
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}
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static int kvm_s390_vm_set_migration(struct kvm *kvm,
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struct kvm_device_attr *attr)
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{
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int idx, res = -ENXIO;
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mutex_lock(&kvm->lock);
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switch (attr->attr) {
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case KVM_S390_VM_MIGRATION_START:
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idx = srcu_read_lock(&kvm->srcu);
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res = kvm_s390_vm_start_migration(kvm);
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srcu_read_unlock(&kvm->srcu, idx);
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break;
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case KVM_S390_VM_MIGRATION_STOP:
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res = kvm_s390_vm_stop_migration(kvm);
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break;
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default:
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break;
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}
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mutex_unlock(&kvm->lock);
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return res;
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}
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static int kvm_s390_vm_get_migration(struct kvm *kvm,
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struct kvm_device_attr *attr)
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{
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u64 mig = (kvm->arch.migration_state != NULL);
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if (attr->attr != KVM_S390_VM_MIGRATION_STATUS)
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return -ENXIO;
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if (copy_to_user((void __user *)attr->addr, &mig, sizeof(mig)))
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return -EFAULT;
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return 0;
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}
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static int kvm_s390_set_tod_high(struct kvm *kvm, struct kvm_device_attr *attr)
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{
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u8 gtod_high;
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@@ -1090,6 +1214,9 @@ static int kvm_s390_vm_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
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case KVM_S390_VM_CRYPTO:
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ret = kvm_s390_vm_set_crypto(kvm, attr);
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break;
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case KVM_S390_VM_MIGRATION:
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ret = kvm_s390_vm_set_migration(kvm, attr);
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break;
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default:
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ret = -ENXIO;
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break;
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@@ -1112,6 +1239,9 @@ static int kvm_s390_vm_get_attr(struct kvm *kvm, struct kvm_device_attr *attr)
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case KVM_S390_VM_CPU_MODEL:
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ret = kvm_s390_get_cpu_model(kvm, attr);
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break;
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case KVM_S390_VM_MIGRATION:
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ret = kvm_s390_vm_get_migration(kvm, attr);
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break;
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default:
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ret = -ENXIO;
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break;
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@@ -1179,6 +1309,9 @@ static int kvm_s390_vm_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
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break;
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}
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break;
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case KVM_S390_VM_MIGRATION:
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ret = 0;
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break;
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default:
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ret = -ENXIO;
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break;
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@@ -1633,6 +1766,10 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
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kvm_s390_destroy_adapters(kvm);
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kvm_s390_clear_float_irqs(kvm);
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kvm_s390_vsie_destroy(kvm);
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if (kvm->arch.migration_state) {
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vfree(kvm->arch.migration_state->pgste_bitmap);
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kfree(kvm->arch.migration_state);
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}
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KVM_EVENT(3, "vm 0x%pK destroyed", kvm);
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}
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@@ -1977,7 +2114,6 @@ int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu)
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if (!vcpu->arch.sie_block->cbrlo)
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return -ENOMEM;
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vcpu->arch.sie_block->ecb2 |= ECB2_CMMA;
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vcpu->arch.sie_block->ecb2 &= ~ECB2_PFMFI;
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return 0;
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}
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@@ -2489,6 +2625,27 @@ retry:
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goto retry;
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}
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if (kvm_check_request(KVM_REQ_START_MIGRATION, vcpu)) {
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/*
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* Disable CMMA virtualization; we will emulate the ESSA
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* instruction manually, in order to provide additional
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* functionalities needed for live migration.
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*/
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vcpu->arch.sie_block->ecb2 &= ~ECB2_CMMA;
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goto retry;
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}
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if (kvm_check_request(KVM_REQ_STOP_MIGRATION, vcpu)) {
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/*
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* Re-enable CMMA virtualization if CMMA is available and
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* was used.
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*/
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if ((vcpu->kvm->arch.use_cmma) &&
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(vcpu->kvm->mm->context.use_cmma))
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vcpu->arch.sie_block->ecb2 |= ECB2_CMMA;
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goto retry;
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}
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/* nothing to do, just clear the request */
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kvm_clear_request(KVM_REQ_UNHALT, vcpu);
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