From patchwork Thu May 7 21:03:34 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 22396 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n47LAG0q015269 for ; Thu, 7 May 2009 21:10:17 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754543AbZEGVKO (ORCPT ); Thu, 7 May 2009 17:10:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754919AbZEGVKO (ORCPT ); Thu, 7 May 2009 17:10:14 -0400 Received: from mx2.redhat.com ([66.187.237.31]:45211 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754356AbZEGVKA (ORCPT ); Thu, 7 May 2009 17:10:00 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n47LA1xJ016604 for ; Thu, 7 May 2009 17:10:01 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n47L9xKI013880; Thu, 7 May 2009 17:09:59 -0400 Received: from amt.cnet (vpn-10-52.str.redhat.com [10.32.10.52]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n47L9vww017558; Thu, 7 May 2009 17:09:58 -0400 Received: from amt.cnet (amt.cnet [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id 60DC2682366; Thu, 7 May 2009 18:07:51 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.3/8.14.3/Submit) id n47L7jLF008058; Thu, 7 May 2009 18:07:45 -0300 Message-Id: <20090507210534.058747069@amt.cnet> User-Agent: quilt/0.47-1 Date: Thu, 07 May 2009 18:03:34 -0300 From: mtosatti@redhat.com To: kvm@vger.kernel.org Cc: avi@redhat.com, Marcelo Tosatti Subject: [patch 3/4] KVM: introduce kvm_arch_can_free_memslot, disallow slot deletion if cached cr3 References: <20090507210331.370806285@amt.cnet> Content-Disposition: inline; filename=verify-cr3 X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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. v2: - set KVM_REQ_TRIPLE_FAULT - use __KVM_HAVE_ARCH_CAN_FREE_MEMSLOT to avoid duplication of stub Signed-off-by: Marcelo Tosatti --- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: kvm-pending/arch/x86/kvm/x86.c =================================================================== --- kvm-pending.orig/arch/x86/kvm/x86.c +++ kvm-pending/arch/x86/kvm/x86.c @@ -1636,6 +1636,29 @@ 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) { + set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests); + 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 @@ -1666,6 +1689,19 @@ 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; @@ -1682,6 +1718,9 @@ 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; } @@ -4552,6 +4591,15 @@ 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-pending/include/linux/kvm_host.h =================================================================== --- kvm-pending.orig/include/linux/kvm_host.h +++ kvm-pending/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-pending/virt/kvm/kvm_main.c =================================================================== --- kvm-pending.orig/virt/kvm/kvm_main.c +++ kvm-pending/virt/kvm/kvm_main.c @@ -1061,6 +1061,13 @@ static int kvm_vm_release(struct inode * return 0; } +#ifndef __KVM_HAVE_ARCH_CAN_FREE_MEMSLOT +int kvm_arch_can_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) +{ + return 1; +} +#endif + /* * Allocate some memory and give it an address in the guest physical address * space. @@ -1179,8 +1186,13 @@ 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) Index: kvm-pending/arch/x86/include/asm/kvm.h =================================================================== --- kvm-pending.orig/arch/x86/include/asm/kvm.h +++ kvm-pending/arch/x86/include/asm/kvm.h @@ -18,6 +18,8 @@ #define __KVM_HAVE_GUEST_DEBUG #define __KVM_HAVE_MSIX +#define __KVM_HAVE_ARCH_CAN_FREE_MEMSLOT + /* Architectural interrupt line count. */ #define KVM_NR_INTERRUPTS 256