[RFC PATCH 18/37] KVM: x86/mmu: Add common API for creating TDP PTEs

David Matlack
2022-12-08T20:33:04Z

Introduce an API for construction of TDP PTEs.

- tdp_mmu_make_leaf_pte()
- tdp_mmu_make_nonleaf_pte()
- tdp_mmu_make_huge_page_split_pte()
- tdp_mmu_make_changed_pte_notifier_pte()

This will be used in a future commit to move the TDP MMU to common code,
while PTE construction will stay in the architecture-specific code.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
---
arch/x86/include/asm/kvm/tdp_pgtable.h | 10 +++++++
arch/x86/kvm/mmu/tdp_mmu.c | 18 +++++--------
arch/x86/kvm/mmu/tdp_pgtable.c | 36 ++++++++++++++++++++++++++
3 files changed, 52 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/kvm/tdp_pgtable.h b/arch/x86/include/asm/kvm/tdp_pgtable.h
index c5c4e4cab24a..ff2691ced38b 100644
--- a/arch/x86/include/asm/kvm/tdp_pgtable.h
+++ b/arch/x86/include/asm/kvm/tdp_pgtable.h
@@ -4,6 +4,7 @@

#include <linux/types.h>
#include <linux/kvm_types.h>
+#include <kvm/mmu_types.h>

struct kvm_mmu_page *tdp_mmu_root(struct kvm_vcpu *vcpu);

@@ -57,4 +58,13 @@ kvm_pfn_t tdp_pte_to_pfn(u64 pte);

void tdp_pte_check_leaf_invariants(u64 pte);

+struct tdp_iter;
+
+u64 tdp_mmu_make_leaf_pte(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+ struct tdp_iter *iter, bool *wrprot);
+u64 tdp_mmu_make_nonleaf_pte(struct kvm_mmu_page *sp);
+u64 tdp_mmu_make_changed_pte_notifier_pte(struct tdp_iter *iter,
+ struct kvm_gfn_range *range);
+u64 tdp_mmu_make_huge_page_split_pte(struct kvm *kvm, u64 huge_spte,
+ struct kvm_mmu_page *sp, int index);
#endif /* !__ASM_KVM_TDP_PGTABLE_H */
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 8155a9e79203..0172b0e44817 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1057,17 +1057,13 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
struct tdp_iter *iter)
{
struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(iter->sptep));
- u64 new_spte;
int ret = RET_PF_FIXED;
bool wrprot = false;
+ u64 new_spte;

WARN_ON(sp->role.level != fault->goal_level);
- if (unlikely(!fault->slot))
- new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
- else
- wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn,
- fault->pfn, iter->old_spte, fault->prefetch, true,
- fault->map_writable, &new_spte);
+
+ new_spte = tdp_mmu_make_leaf_pte(vcpu, fault, iter, &wrprot);

if (new_spte == iter->old_spte)
ret = RET_PF_SPURIOUS;
@@ -1117,7 +1113,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
static int tdp_mmu_link_sp(struct kvm *kvm, struct tdp_iter *iter,
struct kvm_mmu_page *sp, bool shared)
{
- u64 spte = make_nonleaf_spte(sp->spt, !kvm_ad_enabled());
+ u64 spte = tdp_mmu_make_nonleaf_pte(sp);
int ret = 0;

if (shared) {
@@ -1312,9 +1308,7 @@ static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter,
tdp_mmu_set_spte(kvm, iter, 0);

if (!pte_write(range->pte)) {
- new_spte = kvm_mmu_changed_pte_notifier_make_spte(iter->old_spte,
- pte_pfn(range->pte));
-
+ new_spte = tdp_mmu_make_changed_pte_notifier_pte(iter, range);
tdp_mmu_set_spte(kvm, iter, new_spte);
}

@@ -1466,7 +1460,7 @@ static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter,
* not been linked in yet and thus is not reachable from any other CPU.
*/
for (i = 0; i < TDP_PTES_PER_PAGE; i++)
- sp->spt[i] = make_huge_page_split_spte(kvm, huge_spte, sp->role, i);
+ sp->spt[i] = tdp_mmu_make_huge_page_split_pte(kvm, huge_spte, sp, i);

/*
* Replace the huge spte with a pointer to the populated lower level
diff --git a/arch/x86/kvm/mmu/tdp_pgtable.c b/arch/x86/kvm/mmu/tdp_pgtable.c
index 97cc900e8818..e036ba0c6bee 100644
--- a/arch/x86/kvm/mmu/tdp_pgtable.c
+++ b/arch/x86/kvm/mmu/tdp_pgtable.c
@@ -5,6 +5,7 @@

#include "mmu.h"
#include "spte.h"
+#include "tdp_iter.h"

/* Removed SPTEs must not be misconstrued as shadow present PTEs. */
static_assert(!(REMOVED_TDP_PTE & SPTE_MMU_PRESENT_MASK));
@@ -75,3 +76,38 @@ void tdp_pte_check_leaf_invariants(u64 pte)
check_spte_writable_invariants(pte);
}

+u64 tdp_mmu_make_leaf_pte(struct kvm_vcpu *vcpu,
+ struct kvm_page_fault *fault,
+ struct tdp_iter *iter,
+ bool *wrprot)
+{
+ struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(iter->sptep));
+ u64 new_spte;
+
+ if (unlikely(!fault->slot))
+ return make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
+
+ *wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn,
+ fault->pfn, iter->old_spte, fault->prefetch, true,
+ fault->map_writable, &new_spte);
+
+ return new_spte;
+}
+
+u64 tdp_mmu_make_nonleaf_pte(struct kvm_mmu_page *sp)
+{
+ return make_nonleaf_spte(sp->spt, !kvm_ad_enabled());
+}
+
+u64 tdp_mmu_make_changed_pte_notifier_pte(struct tdp_iter *iter,
+ struct kvm_gfn_range *range)
+{
+ return kvm_mmu_changed_pte_notifier_make_spte(iter->old_spte,
+ pte_pfn(range->pte));
+}
+
+u64 tdp_mmu_make_huge_page_split_pte(struct kvm *kvm, u64 huge_spte,
+ struct kvm_mmu_page *sp, int index)
+{
+ return make_huge_page_split_spte(kvm, huge_spte, sp->role, index);
+}
--
2.39.0.rc1.256.g54fd8350bd-goog