[PATCH v12 40/84] KVM: x86/mmu: Add helper to "finish" handling a guest page fault

Sean Christopherson
2024-07-27T00:09:26Z

Add a helper to finish/complete the handling of a guest page, e.g. to
mark the pages accessed and put any held references. In the near
future, this will allow improving the logic without having to copy+paste
changes into all page fault paths. And in the less near future, will
allow sharing the "finish" API across all architectures.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 12 +++++++++---
arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index e76f64f55c4a..1cdd67707461 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4311,6 +4311,12 @@ static u8 kvm_max_private_mapping_level(struct kvm *kvm, kvm_pfn_t pfn,
return req_max_level;
}

+static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu,
+ struct kvm_page_fault *fault, int r)
+{
+ kvm_release_pfn_clean(fault->pfn);
+}
+
static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu,
struct kvm_page_fault *fault)
{
@@ -4476,7 +4482,7 @@ static int kvm_mmu_faultin_pfn(struct kvm_vcpu *vcpu,
* mmu_lock is acquired.
*/
if (mmu_invalidate_retry_gfn_unsafe(vcpu->kvm, fault->mmu_seq, fault->gfn)) {
- kvm_release_pfn_clean(fault->pfn);
+ kvm_mmu_finish_page_fault(vcpu, fault, RET_PF_RETRY);
return RET_PF_RETRY;
}

@@ -4552,8 +4558,8 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
r = direct_map(vcpu, fault);

out_unlock:
+ kvm_mmu_finish_page_fault(vcpu, fault, r);
write_unlock(&vcpu->kvm->mmu_lock);
- kvm_release_pfn_clean(fault->pfn);
return r;
}

@@ -4641,8 +4647,8 @@ static int kvm_tdp_mmu_page_fault(struct kvm_vcpu *vcpu,
r = kvm_tdp_mmu_map(vcpu, fault);

out_unlock:
+ kvm_mmu_finish_page_fault(vcpu, fault, r);
read_unlock(&vcpu->kvm->mmu_lock);
- kvm_release_pfn_clean(fault->pfn);
return r;
}
#endif
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index e1c2f098d9d5..b6897916c76b 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -835,8 +835,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
r = FNAME(fetch)(vcpu, fault, &walker);

out_unlock:
+ kvm_mmu_finish_page_fault(vcpu, fault, r);
write_unlock(&vcpu->kvm->mmu_lock);
- kvm_release_pfn_clean(fault->pfn);
return r;
}