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Commit 2001825e authored by Alexey Kardashevskiy's avatar Alexey Kardashevskiy Committed by Paul Mackerras
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KVM: PPC: Book3S HV: Avoid lockdep debugging in TCE realmode handlers 



The kvmppc_tce_to_ua() helper is called from real and virtual modes
and it works fine as long as CONFIG_DEBUG_LOCKDEP is not enabled.
However if the lockdep debugging is on, the lockdep will most likely break
in kvm_memslots() because of srcu_dereference_check() so we need to use
PPC-own kvm_memslots_raw() which uses realmode safe
rcu_dereference_raw_notrace().

This creates a realmode copy of kvmppc_tce_to_ua() which replaces
kvm_memslots() with kvm_memslots_raw().

Since kvmppc_rm_tce_to_ua() becomes static and can only be used inside
HV KVM, this moves it earlier under CONFIG_KVM_BOOK3S_HV_POSSIBLE.

This moves truly virtual-mode kvmppc_tce_to_ua() to where it belongs and
drops the prmap parameter which was never used in the virtual mode.

Fixes: d3695aa4 ("KVM: PPC: Add support for multiple-TCE hcalls", 2016-02-15)
Signed-off-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent 3309bec8

arch/powerpc/include/asm/kvm_ppc.h

+0 −2
Original line number Diff line number Diff line
@@ -197,8 +197,6 @@ extern struct kvmppc_spapr_tce_table *kvmppc_find_table( 
		(iommu_tce_check_ioba((stt)->page_shift, (stt)->offset, \

				(stt)->size, (ioba), (npages)) ?        \

				H_PARAMETER : H_SUCCESS)

extern long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,

		unsigned long *ua, unsigned long **prmap);

extern void kvmppc_tce_put(struct kvmppc_spapr_tce_table *tt,

		unsigned long idx, unsigned long tce);

extern long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,

arch/powerpc/kvm/book3s_64_vio.c

+20 −4
Original line number Diff line number Diff line
@@ -363,6 +363,22 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, 
	return ret;

}



static long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,

		unsigned long *ua)

{

	unsigned long gfn = tce >> PAGE_SHIFT;

	struct kvm_memory_slot *memslot;



	memslot = search_memslots(kvm_memslots(kvm), gfn);

	if (!memslot)

		return -EINVAL;



	*ua = __gfn_to_hva_memslot(memslot, gfn) |

		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));



	return 0;

}



static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt,

		unsigned long tce)

{
@@ -378,7 +394,7 @@ static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, 
	if (iommu_tce_check_gpa(stt->page_shift, gpa))

		return H_TOO_HARD;



	if (kvmppc_tce_to_ua(stt->kvm, tce, &ua, NULL))

	if (kvmppc_tce_to_ua(stt->kvm, tce, &ua))

		return H_TOO_HARD;



	list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {
@@ -551,7 +567,7 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, 


	dir = iommu_tce_direction(tce);



	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua, NULL)) {

	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {

		ret = H_PARAMETER;

		goto unlock_exit;

	}
@@ -612,7 +628,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		return ret;



	idx = srcu_read_lock(&vcpu->kvm->srcu);

	if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua, NULL)) {

	if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua)) {

		ret = H_TOO_HARD;

		goto unlock_exit;

	}
@@ -647,7 +663,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		}

		tce = be64_to_cpu(tce);



		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua, NULL))

		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua))

			return H_PARAMETER;



		list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {

arch/powerpc/kvm/book3s_64_vio_hv.c

+24 −27
Original line number Diff line number Diff line
@@ -88,6 +88,25 @@ struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm *kvm, 
EXPORT_SYMBOL_GPL(kvmppc_find_table);



#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

static long kvmppc_rm_tce_to_ua(struct kvm *kvm, unsigned long tce,

		unsigned long *ua, unsigned long **prmap)

{

	unsigned long gfn = tce >> PAGE_SHIFT;

	struct kvm_memory_slot *memslot;



	memslot = search_memslots(kvm_memslots_raw(kvm), gfn);

	if (!memslot)

		return -EINVAL;



	*ua = __gfn_to_hva_memslot(memslot, gfn) |

		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));



	if (prmap)

		*prmap = &memslot->arch.rmap[gfn - memslot->base_gfn];



	return 0;

}



/*

 * Validates TCE address.

 * At the moment flags and page mask are validated.
@@ -111,7 +130,7 @@ static long kvmppc_rm_tce_validate(struct kvmppc_spapr_tce_table *stt, 
	if (iommu_tce_check_gpa(stt->page_shift, gpa))

		return H_PARAMETER;



	if (kvmppc_tce_to_ua(stt->kvm, tce, &ua, NULL))

	if (kvmppc_rm_tce_to_ua(stt->kvm, tce, &ua, NULL))

		return H_TOO_HARD;



	list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
@@ -181,28 +200,6 @@ void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt, 
}

EXPORT_SYMBOL_GPL(kvmppc_tce_put);



long kvmppc_tce_to_ua(struct kvm *kvm, unsigned long tce,

		unsigned long *ua, unsigned long **prmap)

{

	unsigned long gfn = tce >> PAGE_SHIFT;

	struct kvm_memory_slot *memslot;



	memslot = search_memslots(kvm_memslots(kvm), gfn);

	if (!memslot)

		return -EINVAL;



	*ua = __gfn_to_hva_memslot(memslot, gfn) |

		(tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));



#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

	if (prmap)

		*prmap = &memslot->arch.rmap[gfn - memslot->base_gfn];

#endif



	return 0;

}

EXPORT_SYMBOL_GPL(kvmppc_tce_to_ua);



#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

static long iommu_tce_xchg_rm(struct mm_struct *mm, struct iommu_table *tbl,

		unsigned long entry, unsigned long *hpa,
@@ -390,7 +387,7 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, 
		return ret;



	dir = iommu_tce_direction(tce);

	if ((dir != DMA_NONE) && kvmppc_tce_to_ua(vcpu->kvm, tce, &ua, NULL))

	if ((dir != DMA_NONE) && kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL))

		return H_PARAMETER;



	entry = ioba >> stt->page_shift;
@@ -492,7 +489,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		 */

		struct mm_iommu_table_group_mem_t *mem;



		if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua, NULL))

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce_list, &ua, NULL))

			return H_TOO_HARD;



		mem = mm_iommu_lookup_rm(vcpu->kvm->mm, ua, IOMMU_PAGE_SIZE_4K);
@@ -508,7 +505,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		 * We do not require memory to be preregistered in this case

		 * so lock rmap and do __find_linux_pte_or_hugepte().

		 */

		if (kvmppc_tce_to_ua(vcpu->kvm, tce_list, &ua, &rmap))

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce_list, &ua, &rmap))

			return H_TOO_HARD;



		rmap = (void *) vmalloc_to_phys(rmap);
@@ -542,7 +539,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, 
		unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);



		ua = 0;

		if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua, NULL))

		if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL))

			return H_PARAMETER;



		list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {