[PATCH 03/14] KVM: x86/mmu: Split out max mapping level calculation to helper

Sean Christopherson
2021-02-13T00:52:21Z

Factor out the logic for determining the maximum mapping level given a
memslot and a gpa. The helper will be used when zapping collapsible
SPTEs when disabling dirty logging, e.g. to avoid zapping SPTEs that
can't possibly be rebuilt as hugepages.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 37 ++++++++++++++++++++-------------
arch/x86/kvm/mmu/mmu_internal.h | 2 ++
2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 24325bdcd387..9be7fd474b2d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2756,8 +2756,8 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
__direct_pte_prefetch(vcpu, sp, sptep);
}

-static int host_pfn_mapping_level(struct kvm_vcpu *vcpu, gfn_t gfn,
- kvm_pfn_t pfn, struct kvm_memory_slot *slot)
+static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
+ struct kvm_memory_slot *slot)
{
unsigned long hva;
pte_t *pte;
@@ -2776,19 +2776,36 @@ static int host_pfn_mapping_level(struct kvm_vcpu *vcpu, gfn_t gfn,
*/
hva = __gfn_to_hva_memslot(slot, gfn);

- pte = lookup_address_in_mm(vcpu->kvm->mm, hva, &level);
+ pte = lookup_address_in_mm(kvm->mm, hva, &level);
if (unlikely(!pte))
return PG_LEVEL_4K;

return level;
}

+int kvm_mmu_max_mapping_level(struct kvm *kvm, struct kvm_memory_slot *slot,
+ gfn_t gfn, kvm_pfn_t pfn, int max_level)
+{
+ struct kvm_lpage_info *linfo;
+
+ max_level = min(max_level, max_huge_page_level);
+ for ( ; max_level > PG_LEVEL_4K; max_level--) {
+ linfo = lpage_info_slot(gfn, slot, max_level);
+ if (!linfo->disallow_lpage)
+ break;
+ }
+
+ if (max_level == PG_LEVEL_4K)
+ return PG_LEVEL_4K;
+
+ return host_pfn_mapping_level(kvm, gfn, pfn, slot);
+}
+
int kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t gfn,
int max_level, kvm_pfn_t *pfnp,
bool huge_page_disallowed, int *req_level)
{
struct kvm_memory_slot *slot;
- struct kvm_lpage_info *linfo;
kvm_pfn_t pfn = *pfnp;
kvm_pfn_t mask;
int level;
@@ -2805,17 +2822,7 @@ int kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t gfn,
if (!slot)
return PG_LEVEL_4K;

- max_level = min(max_level, max_huge_page_level);
- for ( ; max_level > PG_LEVEL_4K; max_level--) {
- linfo = lpage_info_slot(gfn, slot, max_level);
- if (!linfo->disallow_lpage)
- break;
- }
-
- if (max_level == PG_LEVEL_4K)
- return PG_LEVEL_4K;
-
- level = host_pfn_mapping_level(vcpu, gfn, pfn, slot);
+ level = kvm_mmu_max_mapping_level(vcpu->kvm, slot, gfn, pfn, max_level);
if (level == PG_LEVEL_4K)
return level;

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 9e38d3c5daad..0b55aa561ec8 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -138,6 +138,8 @@ enum {
#define SET_SPTE_NEED_REMOTE_TLB_FLUSH BIT(1)
#define SET_SPTE_SPURIOUS BIT(2)

+int kvm_mmu_max_mapping_level(struct kvm *kvm, struct kvm_memory_slot *slot,
+ gfn_t gfn, kvm_pfn_t pfn, int max_level);
int kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, gfn_t gfn,
int max_level, kvm_pfn_t *pfnp,
bool huge_page_disallowed, int *req_level);
--
2.30.0.478.g8a0d178c01-goog