[PATCH v12 59/84] KVM: PPC: Use __kvm_faultin_pfn() to handle page faults on Book3s HV

Sean Christopherson
2024-07-27T00:24:16Z

Replace Book3s HV's homebrewed fault-in logic with __kvm_faultin_pfn(),
which functionally does pretty much the exact same thing.

Note, when the code was written, KVM indeed didn't do fast GUP without
"!atomic && !async", but that has long since changed (KVM tries fast GUP
for all writable mappings).

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 25 ++++---------------------
1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 2f1d58984b41..f305395cf26e 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -603,27 +603,10 @@ int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
write_ok = writing;
hva = gfn_to_hva_memslot(memslot, gfn);

- /*
- * Do a fast check first, since __gfn_to_pfn_memslot doesn't
- * do it with !atomic && !async, which is how we call it.
- * We always ask for write permission since the common case
- * is that the page is writable.
- */
- if (get_user_page_fast_only(hva, FOLL_WRITE, &page)) {
- write_ok = true;
- } else {
- /* Call KVM generic code to do the slow-path check */
- pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
- writing, &write_ok);
- if (is_error_noslot_pfn(pfn))
- return -EFAULT;
- page = NULL;
- if (pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- if (PageReserved(page))
- page = NULL;
- }
- }
+ pfn = __kvm_faultin_pfn(memslot, gfn, writing ? FOLL_WRITE : 0,
+ &write_ok, &page);
+ if (is_error_noslot_pfn(pfn))
+ return -EFAULT;

/*
* Read the PTE from the process' radix tree and use that