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KVM: arm64: nv: Handle VNCR_EL2 invalidation from MMU notifiers

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During an invalidation triggered by an MMU notifier, we need to
make sure we can drop the *host* mapping that would have been
translated by the stage-2 mapping being invalidated.

For the moment, the invalidation is pretty brutal, as we nuke
the full IPA range, and therefore any VNCR_EL2 mapping.

At some point, we'll be more light-weight, and the code is able
to deal with something more targetted.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250514103501.2225951-12-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2025-05-14 11:34:54 +01:00
parent 2a359e0725
commit 7270cc9157
1 changed files with 75 additions and 0 deletions
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75
arch/arm64/kvm/nested.c
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@ -434,6 +434,30 @@ static unsigned int ttl_to_size(u8 ttl)
return max_size; return max_size;
} }
static u8 pgshift_level_to_ttl(u16 shift, u8 level)
{
u8 ttl;
switch(shift) {
case 12:
ttl = TLBI_TTL_TG_4K;
break;
case 14:
ttl = TLBI_TTL_TG_16K;
break;
case 16:
ttl = TLBI_TTL_TG_64K;
break;
default:
BUG();
}
ttl <<= 2;
ttl |= level & 3;
return ttl;
}
/* /*
* Compute the equivalent of the TTL field by parsing the shadow PT. The * Compute the equivalent of the TTL field by parsing the shadow PT. The
* granule size is extracted from the cached VTCR_EL2.TG0 while the level is * granule size is extracted from the cached VTCR_EL2.TG0 while the level is
@ -784,6 +808,53 @@ int kvm_inject_s2_fault(struct kvm_vcpu *vcpu, u64 esr_el2)
return kvm_inject_nested_sync(vcpu, esr_el2); return kvm_inject_nested_sync(vcpu, esr_el2);
} }
static void invalidate_vncr(struct vncr_tlb *vt)
{
vt->valid = false;
if (vt->cpu != -1)
clear_fixmap(vncr_fixmap(vt->cpu));
}
static void kvm_invalidate_vncr_ipa(struct kvm *kvm, u64 start, u64 end)
{
struct kvm_vcpu *vcpu;
unsigned long i;
lockdep_assert_held_write(&kvm->mmu_lock);
if (!kvm_has_feat(kvm, ID_AA64MMFR4_EL1, NV_frac, NV2_ONLY))
return;
kvm_for_each_vcpu(i, vcpu, kvm) {
struct vncr_tlb *vt = vcpu->arch.vncr_tlb;
u64 ipa_start, ipa_end, ipa_size;
/*
* Careful here: We end-up here from an MMU notifier,
* and this can race against a vcpu not being onlined
* yet, without the pseudo-TLB being allocated.
*
* Skip those, as they obviously don't participate in
* the invalidation at this stage.
*/
if (!vt)
continue;
if (!vt->valid)
continue;
ipa_size = ttl_to_size(pgshift_level_to_ttl(vt->wi.pgshift,
vt->wr.level));
ipa_start = vt->wr.pa & (ipa_size - 1);
ipa_end = ipa_start + ipa_size;
if (ipa_end <= start || ipa_start >= end)
continue;
invalidate_vncr(vt);
}
}
void kvm_nested_s2_wp(struct kvm *kvm) void kvm_nested_s2_wp(struct kvm *kvm)
{ {
int i; int i;
@ -796,6 +867,8 @@ void kvm_nested_s2_wp(struct kvm *kvm)
if (kvm_s2_mmu_valid(mmu)) if (kvm_s2_mmu_valid(mmu))
kvm_stage2_wp_range(mmu, 0, kvm_phys_size(mmu)); kvm_stage2_wp_range(mmu, 0, kvm_phys_size(mmu));
} }
kvm_invalidate_vncr_ipa(kvm, 0, BIT(kvm->arch.mmu.pgt->ia_bits));
} }
void kvm_nested_s2_unmap(struct kvm *kvm, bool may_block) void kvm_nested_s2_unmap(struct kvm *kvm, bool may_block)
@ -810,6 +883,8 @@ void kvm_nested_s2_unmap(struct kvm *kvm, bool may_block)
if (kvm_s2_mmu_valid(mmu)) if (kvm_s2_mmu_valid(mmu))
kvm_stage2_unmap_range(mmu, 0, kvm_phys_size(mmu), may_block); kvm_stage2_unmap_range(mmu, 0, kvm_phys_size(mmu), may_block);
} }
kvm_invalidate_vncr_ipa(kvm, 0, BIT(kvm->arch.mmu.pgt->ia_bits));
} }
void kvm_nested_s2_flush(struct kvm *kvm) void kvm_nested_s2_flush(struct kvm *kvm)