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KVM: x86/mmu: Derive page role for TDP MMU shadow pages from parent

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Derive the page role from the parent shadow page, since the only thing
that changes is the level. This is in preparation for splitting huge
pages during VM-ioctls which do not have access to the vCPU MMU context.

No functional change intended.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220119230739.2234394-14-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
David Matlack 2022-01-19 23:07:34 +00:00 committed by Paolo Bonzini
parent a81399a573
commit a3aca4de0d
1 changed files with 19 additions and 18 deletions
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37
arch/x86/kvm/mmu/tdp_mmu.c
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@ -171,19 +171,8 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
if (kvm_mmu_page_as_id(_root) != _as_id) { \
} else
static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu,
int level)
{
union kvm_mmu_page_role role;
role = vcpu->arch.mmu->mmu_role.base;
role.level = level;
return role;
}
static struct kvm_mmu_page *tdp_mmu_alloc_sp(struct kvm_vcpu *vcpu, gfn_t gfn,
int level)
union kvm_mmu_page_role role)
{
struct kvm_mmu_page *sp;
@ -191,7 +180,7 @@ static struct kvm_mmu_page *tdp_mmu_alloc_sp(struct kvm_vcpu *vcpu, gfn_t gfn,
sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache);
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
sp->role.word = page_role_for_level(vcpu, level).word;
sp->role = role;
sp->gfn = gfn;
sp->tdp_mmu_page = true;
@ -200,16 +189,28 @@ static struct kvm_mmu_page *tdp_mmu_alloc_sp(struct kvm_vcpu *vcpu, gfn_t gfn,
return sp;
}
static struct kvm_mmu_page *tdp_mmu_alloc_child_sp(struct kvm_vcpu *vcpu,
struct tdp_iter *iter)
{
struct kvm_mmu_page *parent_sp;
union kvm_mmu_page_role role;
parent_sp = sptep_to_sp(rcu_dereference(iter->sptep));
role = parent_sp->role;
role.level--;
return tdp_mmu_alloc_sp(vcpu, iter->gfn, role);
}
hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
{
union kvm_mmu_page_role role;
union kvm_mmu_page_role role = vcpu->arch.mmu->mmu_role.base;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_page *root;
lockdep_assert_held_write(&kvm->mmu_lock);
role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level);
/*
* Check for an existing root before allocating a new one. Note, the
* role check prevents consuming an invalid root.
@ -220,7 +221,7 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
goto out;
}
root = tdp_mmu_alloc_sp(vcpu, 0, vcpu->arch.mmu->shadow_root_level);
root = tdp_mmu_alloc_sp(vcpu, 0, role);
refcount_set(&root->tdp_mmu_root_count, 1);
spin_lock(&kvm->arch.tdp_mmu_pages_lock);
@ -1041,7 +1042,7 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
if (is_removed_spte(iter.old_spte))
break;
sp = tdp_mmu_alloc_sp(vcpu, iter.gfn, iter.level - 1);
sp = tdp_mmu_alloc_child_sp(vcpu, &iter);
if (tdp_mmu_link_sp_atomic(vcpu->kvm, &iter, sp, account_nx)) {
tdp_mmu_free_sp(sp);
break;