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KVM: PPC: Book3S HV: Avoid lockdep debugging in TCE realmode handlers
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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: d3695aa ("KVM: PPC: Add support for multiple-TCE hcalls", 2016-02-15)
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
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Alexey Kardashevskiy authored and Paul Mackerras committed Apr 30, 2019
1 parent 3309bec commit 2001825
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Showing 3 changed files with 44 additions and 33 deletions.
2 changes: 0 additions & 2 deletions arch/powerpc/include/asm/kvm_ppc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down
24 changes: 20 additions & 4 deletions arch/powerpc/kvm/book3s_64_vio.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand All @@ -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) {
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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) {
Expand Down
51 changes: 24 additions & 27 deletions arch/powerpc/kvm/book3s_64_vio_hv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -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) {
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand Down Expand Up @@ -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) {
Expand Down

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