Disallow the deletion of memory slots (and aliases, for x86 case), if a vcpu contains a cr3 that points to such slot/alias.
This complements commit 6c20e1442bb1c62914bb85b7f4a38973d2a423ba. Signed-off-by: Marcelo Tosatti <[email protected]> Index: kvm/arch/ia64/kvm/kvm-ia64.c =================================================================== --- kvm.orig/arch/ia64/kvm/kvm-ia64.c +++ kvm/arch/ia64/kvm/kvm-ia64.c @@ -1633,6 +1633,11 @@ void kvm_arch_flush_shadow(struct kvm *k kvm_flush_remote_tlbs(kvm); } +int kvm_arch_can_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + return 1; +} + long kvm_arch_dev_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { Index: kvm/arch/powerpc/kvm/powerpc.c =================================================================== --- kvm.orig/arch/powerpc/kvm/powerpc.c +++ kvm/arch/powerpc/kvm/powerpc.c @@ -176,6 +176,11 @@ void kvm_arch_flush_shadow(struct kvm *k { } +int kvm_arch_can_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + return 1; +} + struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) { struct kvm_vcpu *vcpu; Index: kvm/arch/s390/kvm/kvm-s390.c =================================================================== --- kvm.orig/arch/s390/kvm/kvm-s390.c +++ kvm/arch/s390/kvm/kvm-s390.c @@ -691,6 +691,11 @@ void kvm_arch_flush_shadow(struct kvm *k { } +int kvm_arch_can_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + return 1; +} + gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn) { return gfn; Index: kvm/arch/x86/kvm/x86.c =================================================================== --- kvm.orig/arch/x86/kvm/x86.c +++ kvm/arch/x86/kvm/x86.c @@ -1676,6 +1676,27 @@ gfn_t unalias_gfn(struct kvm *kvm, gfn_t return gfn; } +static int kvm_root_gfn_in_range(struct kvm *kvm, gfn_t base_gfn, + gfn_t end_gfn, bool unalias) +{ + struct kvm_vcpu *vcpu; + gfn_t root_gfn; + int i; + + for (i = 0; i < KVM_MAX_VCPUS; ++i) { + vcpu = kvm->vcpus[i]; + if (!vcpu) + continue; + root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT; + if (unalias) + root_gfn = unalias_gfn(kvm, root_gfn); + if (root_gfn >= base_gfn && root_gfn <= end_gfn) + return 1; + } + + return 0; +} + /* * Set a new alias region. Aliases map a portion of physical memory into * another portion. This is useful for memory windows, for example the PC @@ -1706,6 +1727,19 @@ static int kvm_vm_ioctl_set_memory_alias spin_lock(&kvm->mmu_lock); p = &kvm->arch.aliases[alias->slot]; + + /* FIXME: either disallow shrinking alias slots or disable + * size changes as done with memslots + */ + if (!alias->memory_size) { + r = -EBUSY; + if (kvm_root_gfn_in_range(kvm, p->base_gfn, + p->base_gfn + p->npages - 1, + false)) + goto out_unlock; + } + + p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT; p->npages = alias->memory_size >> PAGE_SHIFT; p->target_gfn = alias->target_phys_addr >> PAGE_SHIFT; @@ -1722,6 +1756,9 @@ static int kvm_vm_ioctl_set_memory_alias return 0; +out_unlock: + spin_unlock(&kvm->mmu_lock); + up_write(&kvm->slots_lock); out: return r; } @@ -4532,6 +4569,15 @@ void kvm_arch_flush_shadow(struct kvm *k kvm_mmu_zap_all(kvm); } +int kvm_arch_can_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + int ret; + + ret = kvm_root_gfn_in_range(kvm, slot->base_gfn, + slot->base_gfn + slot->npages - 1, true); + return !ret; +} + int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) { return vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE Index: kvm/include/linux/kvm_host.h =================================================================== --- kvm.orig/include/linux/kvm_host.h +++ kvm/include/linux/kvm_host.h @@ -200,6 +200,7 @@ int kvm_arch_set_memory_region(struct kv struct kvm_memory_slot old, int user_alloc); void kvm_arch_flush_shadow(struct kvm *kvm); +int kvm_arch_can_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot); gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn); struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn); unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn); Index: kvm/virt/kvm/kvm_main.c =================================================================== --- kvm.orig/virt/kvm/kvm_main.c +++ kvm/virt/kvm/kvm_main.c @@ -1179,8 +1179,13 @@ int __kvm_set_memory_region(struct kvm * } #endif /* not defined CONFIG_S390 */ - if (!npages) + if (!npages) { kvm_arch_flush_shadow(kvm); + if (!kvm_arch_can_free_memslot(kvm, memslot)) { + r = -EBUSY; + goto out_free; + } + } spin_lock(&kvm->mmu_lock); if (mem->slot >= kvm->nmemslots) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
