Commit 22945688 authored by Bharata B Rao's avatar Bharata B Rao Committed by Paul Mackerras
Browse files

KVM: PPC: Book3S HV: Support reset of secure guest 



Add support for reset of secure guest via a new ioctl KVM_PPC_SVM_OFF.
This ioctl will be issued by QEMU during reset and includes the
the following steps:

- Release all device pages of the secure guest.
- Ask UV to terminate the guest via UV_SVM_TERMINATE ucall
- Unpin the VPA pages so that they can be migrated back to secure
  side when guest becomes secure again. This is required because
  pinned pages can't be migrated.
- Reinit the partition scoped page tables

After these steps, guest is ready to issue UV_ESM call once again
to switch to secure mode.

Signed-off-by: default avatarBharata B Rao <bharata@linux.ibm.com>
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
	[Implementation of uv_svm_terminate() and its call from
	guest shutdown path]
Signed-off-by: default avatarRam Pai <linuxram@us.ibm.com>
	[Unpinning of VPA pages]
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent c3262257

Documentation/virt/kvm/api.txt

+18 −0
Original line number Diff line number Diff line
@@ -4149,6 +4149,24 @@ Valid values for 'action': 
#define KVM_PMU_EVENT_ALLOW 0

#define KVM_PMU_EVENT_DENY 1



4.121 KVM_PPC_SVM_OFF



Capability: basic

Architectures: powerpc

Type: vm ioctl

Parameters: none

Returns: 0 on successful completion,

Errors:

  EINVAL:    if ultravisor failed to terminate the secure guest

  ENOMEM:    if hypervisor failed to allocate new radix page tables for guest



This ioctl is used to turn off the secure mode of the guest or transition

the guest from secure mode to normal mode. This is invoked when the guest

is reset. This has no effect if called for a normal guest.



This ioctl issues an ultravisor call to terminate the secure guest,

unpins the VPA pages and releases all the device pages that are used to

track the secure pages by hypervisor.



5. The kvm_run structure

------------------------

arch/powerpc/include/asm/kvm_ppc.h

+1 −0
Original line number Diff line number Diff line
@@ -322,6 +322,7 @@ struct kvmppc_ops { 
			       int size);

	int (*store_to_eaddr)(struct kvm_vcpu *vcpu, ulong *eaddr, void *ptr,

			      int size);

	int (*svm_off)(struct kvm *kvm);

};



extern struct kvmppc_ops *kvmppc_hv_ops;

arch/powerpc/include/asm/ultravisor-api.h

+1 −0
Original line number Diff line number Diff line
@@ -34,5 +34,6 @@ 
#define UV_UNSHARE_PAGE			0xF134

#define UV_UNSHARE_ALL_PAGES		0xF140

#define UV_PAGE_INVAL			0xF138

#define UV_SVM_TERMINATE		0xF13C



#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */

arch/powerpc/include/asm/ultravisor.h

+5 −0
Original line number Diff line number Diff line
@@ -77,4 +77,9 @@ static inline int uv_page_inval(u64 lpid, u64 gpa, u64 page_shift) 
	return ucall_norets(UV_PAGE_INVAL, lpid, gpa, page_shift);

}



static inline int uv_svm_terminate(u64 lpid)

{

	return ucall_norets(UV_SVM_TERMINATE, lpid);

}



#endif	/* _ASM_POWERPC_ULTRAVISOR_H */

arch/powerpc/kvm/book3s_hv.c

+90 −0
Original line number Diff line number Diff line
@@ -4983,6 +4983,7 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm) 
		if (nesting_enabled(kvm))

			kvmhv_release_all_nested(kvm);

		kvm->arch.process_table = 0;

		uv_svm_terminate(kvm->arch.lpid);

		kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);

	}
@@ -5425,6 +5426,94 @@ static int kvmhv_store_to_eaddr(struct kvm_vcpu *vcpu, ulong *eaddr, void *ptr, 
	return rc;

}



static void unpin_vpa_reset(struct kvm *kvm, struct kvmppc_vpa *vpa)

{

	unpin_vpa(kvm, vpa);

	vpa->gpa = 0;

	vpa->pinned_addr = NULL;

	vpa->dirty = false;

	vpa->update_pending = 0;

}



/*

 *  IOCTL handler to turn off secure mode of guest

 *

 * - Release all device pages

 * - Issue ucall to terminate the guest on the UV side

 * - Unpin the VPA pages.

 * - Reinit the partition scoped page tables

 */

static int kvmhv_svm_off(struct kvm *kvm)

{

	struct kvm_vcpu *vcpu;

	int mmu_was_ready;

	int srcu_idx;

	int ret = 0;

	int i;



	if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))

		return ret;



	mutex_lock(&kvm->arch.mmu_setup_lock);

	mmu_was_ready = kvm->arch.mmu_ready;

	if (kvm->arch.mmu_ready) {

		kvm->arch.mmu_ready = 0;

		/* order mmu_ready vs. vcpus_running */

		smp_mb();

		if (atomic_read(&kvm->arch.vcpus_running)) {

			kvm->arch.mmu_ready = 1;

			ret = -EBUSY;

			goto out;

		}

	}



	srcu_idx = srcu_read_lock(&kvm->srcu);

	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {

		struct kvm_memory_slot *memslot;

		struct kvm_memslots *slots = __kvm_memslots(kvm, i);



		if (!slots)

			continue;



		kvm_for_each_memslot(memslot, slots) {

			kvmppc_uvmem_drop_pages(memslot, kvm);

			uv_unregister_mem_slot(kvm->arch.lpid, memslot->id);

		}

	}

	srcu_read_unlock(&kvm->srcu, srcu_idx);



	ret = uv_svm_terminate(kvm->arch.lpid);

	if (ret != U_SUCCESS) {

		ret = -EINVAL;

		goto out;

	}



	/*

	 * When secure guest is reset, all the guest pages are sent

	 * to UV via UV_PAGE_IN before the non-boot vcpus get a

	 * chance to run and unpin their VPA pages. Unpinning of all

	 * VPA pages is done here explicitly so that VPA pages

	 * can be migrated to the secure side.

	 *

	 * This is required to for the secure SMP guest to reboot

	 * correctly.

	 */

	kvm_for_each_vcpu(i, vcpu, kvm) {

		spin_lock(&vcpu->arch.vpa_update_lock);

		unpin_vpa_reset(kvm, &vcpu->arch.dtl);

		unpin_vpa_reset(kvm, &vcpu->arch.slb_shadow);

		unpin_vpa_reset(kvm, &vcpu->arch.vpa);

		spin_unlock(&vcpu->arch.vpa_update_lock);

	}



	kvmppc_setup_partition_table(kvm);

	kvm->arch.secure_guest = 0;

	kvm->arch.mmu_ready = mmu_was_ready;

out:

	mutex_unlock(&kvm->arch.mmu_setup_lock);

	return ret;

}



static struct kvmppc_ops kvm_ops_hv = {

	.get_sregs = kvm_arch_vcpu_ioctl_get_sregs_hv,

	.set_sregs = kvm_arch_vcpu_ioctl_set_sregs_hv,
@@ -5468,6 +5557,7 @@ static struct kvmppc_ops kvm_ops_hv = { 
	.enable_nested = kvmhv_enable_nested,

	.load_from_eaddr = kvmhv_load_from_eaddr,

	.store_to_eaddr = kvmhv_store_to_eaddr,

	.svm_off = kvmhv_svm_off,

};



static int kvm_init_subcore_bitmap(void)

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