From: David Stevens <steve...@chromium.org>

Migrate from __gfn_to_pfn_memslot to __kvm_follow_pfn. As part of the
refactoring, remove the redundant calls to get_user_page_fast_only,
since the check for !async && !atomic was removed from the KVM generic
code in b9b33da2aa74. Also, remove the kvm_ro parameter because the KVM
generic code handles RO memslots.

Signed-off-by: David Stevens <steve...@chromium.org>
---
I have checked that this patch compiles, but I don't have the hardware
to test it myself.

 arch/powerpc/include/asm/kvm_book3s.h  |  2 +-
 arch/powerpc/kvm/book3s_64_mmu_hv.c    | 38 +++++++++-----------
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 50 +++++++++++---------------
 arch/powerpc/kvm/book3s_hv_nested.c    |  4 +--
 4 files changed, 38 insertions(+), 56 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_book3s.h 
b/arch/powerpc/include/asm/kvm_book3s.h
index bbf5e2c5fe09..bf48c511e700 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -202,7 +202,7 @@ extern bool kvmppc_hv_handle_set_rc(struct kvm *kvm, bool 
nested,
 extern int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
                                unsigned long gpa,
                                struct kvm_memory_slot *memslot,
-                               bool writing, bool kvm_ro,
+                               bool writing,
                                pte_t *inserted_pte, unsigned int *levelp);
 extern int kvmppc_init_vm_radix(struct kvm *kvm);
 extern void kvmppc_free_radix(struct kvm *kvm);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c 
b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 7f765d5ad436..9a4715e73937 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -523,6 +523,9 @@ int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
        unsigned long rcbits;
        long mmio_update;
        pte_t pte, *ptep;
+       struct kvm_follow_pfn foll = {
+               .allow_write_mapping = true,
+       };
 
        if (kvm_is_radix(kvm))
                return kvmppc_book3s_radix_page_fault(vcpu, ea, dsisr);
@@ -599,29 +602,20 @@ int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
        page = NULL;
        writing = (dsisr & DSISR_ISSTORE) != 0;
        /* If writing != 0, then the HPTE must allow writing, if we get here */
-       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, false, NULL,
-                                          writing, &write_ok, NULL);
-               if (is_error_noslot_pfn(pfn))
-                       return -EFAULT;
-               page = NULL;
-               if (pfn_valid(pfn)) {
-                       page = pfn_to_page(pfn);
-                       if (PageReserved(page))
-                               page = NULL;
-               }
+       foll.slot = memslot;
+       foll.gfn = gfn;
+       foll.flags = FOLL_GET | (writing ? FOLL_WRITE : 0);
+       pfn = __kvm_follow_pfn(&foll);
+       if (is_error_noslot_pfn(pfn))
+               return -EFAULT;
+       page = NULL;
+       write_ok = foll.writable;
+       hva = foll.hva;
+       if (pfn_valid(pfn)) {
+               page = pfn_to_page(pfn);
+               if (PageReserved(page))
+                       page = NULL;
        }
 
        /*
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c 
b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 461307b89c3a..339d1efcb6c9 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -815,47 +815,39 @@ bool kvmppc_hv_handle_set_rc(struct kvm *kvm, bool 
nested, bool writing,
 int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
                                   unsigned long gpa,
                                   struct kvm_memory_slot *memslot,
-                                  bool writing, bool kvm_ro,
+                                  bool writing,
                                   pte_t *inserted_pte, unsigned int *levelp)
 {
        struct kvm *kvm = vcpu->kvm;
        struct page *page = NULL;
        unsigned long mmu_seq;
-       unsigned long hva, gfn = gpa >> PAGE_SHIFT;
-       bool upgrade_write = false;
-       bool *upgrade_p = &upgrade_write;
+       unsigned long hva, pfn, gfn = gpa >> PAGE_SHIFT;
+       bool upgrade_write;
        pte_t pte, *ptep;
        unsigned int shift, level;
        int ret;
        bool large_enable;
+       struct kvm_follow_pfn foll = {
+               .slot = memslot,
+               .gfn = gfn,
+               .flags = FOLL_GET | (writing ? FOLL_WRITE : 0),
+               .allow_write_mapping = true,
+       };
 
        /* used to check for invalidations in progress */
        mmu_seq = kvm->mmu_invalidate_seq;
        smp_rmb();
 
-       /*
-        * 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.
-        */
-       hva = gfn_to_hva_memslot(memslot, gfn);
-       if (!kvm_ro && get_user_page_fast_only(hva, FOLL_WRITE, &page)) {
-               upgrade_write = true;
-       } else {
-               unsigned long pfn;
-
-               /* Call KVM generic code to do the slow-path check */
-               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
-                                          writing, upgrade_p, NULL);
-               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_follow_pfn(&foll);
+       if (is_error_noslot_pfn(pfn))
+               return -EFAULT;
+       page = NULL;
+       hva = foll.hva;
+       upgrade_write = foll.writable;
+       if (pfn_valid(pfn)) {
+               page = pfn_to_page(pfn);
+               if (PageReserved(page))
+                       page = NULL;
        }
 
        /*
@@ -944,7 +936,6 @@ int kvmppc_book3s_radix_page_fault(struct kvm_vcpu *vcpu,
        struct kvm_memory_slot *memslot;
        long ret;
        bool writing = !!(dsisr & DSISR_ISSTORE);
-       bool kvm_ro = false;
 
        /* Check for unusual errors */
        if (dsisr & DSISR_UNSUPP_MMU) {
@@ -997,7 +988,6 @@ int kvmppc_book3s_radix_page_fault(struct kvm_vcpu *vcpu,
                                        ea, DSISR_ISSTORE | DSISR_PROTFAULT);
                        return RESUME_GUEST;
                }
-               kvm_ro = true;
        }
 
        /* Failed to set the reference/change bits */
@@ -1015,7 +1005,7 @@ int kvmppc_book3s_radix_page_fault(struct kvm_vcpu *vcpu,
 
        /* Try to insert a pte */
        ret = kvmppc_book3s_instantiate_page(vcpu, gpa, memslot, writing,
-                                            kvm_ro, NULL, NULL);
+                                            NULL, NULL);
 
        if (ret == 0 || ret == -EAGAIN)
                ret = RESUME_GUEST;
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c 
b/arch/powerpc/kvm/book3s_hv_nested.c
index 377d0b4a05ee..6d531051df04 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -1497,7 +1497,6 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu 
*vcpu,
        unsigned long n_gpa, gpa, gfn, perm = 0UL;
        unsigned int shift, l1_shift, level;
        bool writing = !!(dsisr & DSISR_ISSTORE);
-       bool kvm_ro = false;
        long int ret;
 
        if (!gp->l1_gr_to_hr) {
@@ -1577,7 +1576,6 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu 
*vcpu,
                                        ea, DSISR_ISSTORE | DSISR_PROTFAULT);
                        return RESUME_GUEST;
                }
-               kvm_ro = true;
        }
 
        /* 2. Find the host pte for this L1 guest real address */
@@ -1599,7 +1597,7 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu 
*vcpu,
        if (!pte_present(pte) || (writing && !(pte_val(pte) & _PAGE_WRITE))) {
                /* No suitable pte found -> try to insert a mapping */
                ret = kvmppc_book3s_instantiate_page(vcpu, gpa, memslot,
-                                       writing, kvm_ro, &pte, &level);
+                                       writing, &pte, &level);
                if (ret == -EAGAIN)
                        return RESUME_GUEST;
                else if (ret)
-- 
2.41.0.255.g8b1d071c50-goog

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