Both Christoph Hellwig and Jason Gunthorpe suggested that usage of
follow_pfn by modules should be locked down more. To do so callers
need to be able to pass the mmu_notifier subscription corresponding
to the mm_struct to follow_pfn().

This patch does the rote work of doing that in the kvm subsystem. In
most places this is solved by passing struct kvm * down the call
stacks as an additional parameter, since that contains the
mmu_notifier.

Compile tested on all affected arch.

Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
Cc: Christoph Hellwig <h...@infradead.org>
Cc: Jason Gunthorpe <j...@ziepe.ca>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: John Hubbard <jhubb...@nvidia.com>
Cc: Jérôme Glisse <jgli...@redhat.com>
Cc: Jan Kara <j...@suse.cz>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: linux...@kvack.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-samsung-...@vger.kernel.org
Cc: linux-me...@vger.kernel.org
Cc: k...@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch>
---
 arch/powerpc/kvm/book3s_64_mmu_hv.c    |  2 +-
 arch/powerpc/kvm/book3s_64_mmu_radix.c |  2 +-
 arch/powerpc/kvm/e500_mmu_host.c       |  2 +-
 arch/x86/kvm/mmu/mmu.c                 |  8 ++--
 include/linux/kvm_host.h               |  9 +++--
 virt/kvm/kvm_main.c                    | 52 +++++++++++++++-----------
 6 files changed, 45 insertions(+), 30 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c 
b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 38ea396a23d6..86781ff76fcb 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -589,7 +589,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
                write_ok = true;
        } else {
                /* Call KVM generic code to do the slow-path check */
-               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
+               pfn = __gfn_to_pfn_memslot(kvm, memslot, gfn, false, NULL,
                                           writing, &write_ok);
                if (is_error_noslot_pfn(pfn))
                        return -EFAULT;
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c 
b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index bb35490400e9..319a1a99153f 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -821,7 +821,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
                unsigned long pfn;
 
                /* Call KVM generic code to do the slow-path check */
-               pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
+               pfn = __gfn_to_pfn_memslot(kvm, memslot, gfn, false, NULL,
                                           writing, upgrade_p);
                if (is_error_noslot_pfn(pfn))
                        return -EFAULT;
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index ed0c9c43d0cf..fd2b2d363559 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -446,7 +446,7 @@ static inline int kvmppc_e500_shadow_map(struct 
kvmppc_vcpu_e500 *vcpu_e500,
 
        if (likely(!pfnmap)) {
                tsize_pages = 1UL << (tsize + 10 - PAGE_SHIFT);
-               pfn = gfn_to_pfn_memslot(slot, gfn);
+               pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
                if (is_error_noslot_pfn(pfn)) {
                        if (printk_ratelimit())
                                pr_err("%s: real page not found for gfn %lx\n",
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 1f96adff8dc4..a46e4ae4f8b0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2677,7 +2677,7 @@ static kvm_pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu 
*vcpu, gfn_t gfn,
        if (!slot)
                return KVM_PFN_ERR_FAULT;
 
-       return gfn_to_pfn_memslot_atomic(slot, gfn);
+       return gfn_to_pfn_memslot_atomic(vcpu->kvm, slot, gfn);
 }
 
 static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
@@ -3655,7 +3655,8 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool 
prefault, gfn_t gfn,
        }
 
        async = false;
-       *pfn = __gfn_to_pfn_memslot(slot, gfn, false, &async, write, writable);
+       *pfn = __gfn_to_pfn_memslot(vcpu->kvm, slot, gfn,
+                                   false, &async, write, writable);
        if (!async)
                return false; /* *pfn has correct page already */
 
@@ -3669,7 +3670,8 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool 
prefault, gfn_t gfn,
                        return true;
        }
 
-       *pfn = __gfn_to_pfn_memslot(slot, gfn, false, NULL, write, writable);
+       *pfn = __gfn_to_pfn_memslot(vcpu->kvm, slot, gfn,
+                                   false, NULL, write, writable);
        return false;
 }
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7f2e2a09ebbd..864424ce6b6b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -717,9 +717,12 @@ void kvm_set_page_accessed(struct page *page);
 kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
                      bool *writable);
-kvm_pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn);
-kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn);
-kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
+kvm_pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
+                            struct kvm_memory_slot *slot, gfn_t gfn);
+kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm *kvm,
+                                   struct kvm_memory_slot *slot, gfn_t gfn);
+kvm_pfn_t __gfn_to_pfn_memslot(struct kvm *kvm,
+                              struct kvm_memory_slot *slot, gfn_t gfn,
                               bool atomic, bool *async, bool write_fault,
                               bool *writable);
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2541a17ff1c4..417f3d470c3e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1883,7 +1883,7 @@ static bool vma_is_valid(struct vm_area_struct *vma, bool 
write_fault)
        return true;
 }
 
-static int hva_to_pfn_remapped(struct vm_area_struct *vma,
+static int hva_to_pfn_remapped(struct kvm *kvm, struct vm_area_struct *vma,
                               unsigned long addr, bool *async,
                               bool write_fault, bool *writable,
                               kvm_pfn_t *p_pfn)
@@ -1946,8 +1946,9 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
  * 2): @write_fault = false && @writable, @writable will tell the caller
  *     whether the mapping is writable.
  */
-static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
-                       bool write_fault, bool *writable)
+static kvm_pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr,
+                           bool atomic, bool *async,
+                           bool write_fault, bool *writable)
 {
        struct vm_area_struct *vma;
        kvm_pfn_t pfn = 0;
@@ -1979,7 +1980,8 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool 
atomic, bool *async,
        if (vma == NULL)
                pfn = KVM_PFN_ERR_FAULT;
        else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
-               r = hva_to_pfn_remapped(vma, addr, async, write_fault, 
writable, &pfn);
+               r = hva_to_pfn_remapped(kvm, vma, addr,
+                                       async, write_fault, writable, &pfn);
                if (r == -EAGAIN)
                        goto retry;
                if (r < 0)
@@ -1994,7 +1996,8 @@ static kvm_pfn_t hva_to_pfn(unsigned long addr, bool 
atomic, bool *async,
        return pfn;
 }
 
-kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
+kvm_pfn_t __gfn_to_pfn_memslot(struct kvm *kvm,
+                              struct kvm_memory_slot *slot, gfn_t gfn,
                               bool atomic, bool *async, bool write_fault,
                               bool *writable)
 {
@@ -2018,7 +2021,7 @@ kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot 
*slot, gfn_t gfn,
                writable = NULL;
        }
 
-       return hva_to_pfn(addr, atomic, async, write_fault,
+       return hva_to_pfn(kvm, addr, atomic, async, write_fault,
                          writable);
 }
 EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
@@ -2026,38 +2029,43 @@ EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
                      bool *writable)
 {
-       return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
+       return __gfn_to_pfn_memslot(kvm, gfn_to_memslot(kvm, gfn), gfn,
+                                   false, NULL,
                                    write_fault, writable);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
 
-kvm_pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
+kvm_pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
+                            struct kvm_memory_slot *slot, gfn_t gfn)
 {
-       return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL);
+       return __gfn_to_pfn_memslot(kvm, slot, gfn, false, NULL, true, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
 
-kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn)
+kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm *kvm,
+                                   struct kvm_memory_slot *slot, gfn_t gfn)
 {
-       return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL);
+       return __gfn_to_pfn_memslot(kvm, slot, gfn, true, NULL, true, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
 
 kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
-       return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), 
gfn);
+       return gfn_to_pfn_memslot_atomic(vcpu->kvm,
+                                        kvm_vcpu_gfn_to_memslot(vcpu, gfn), 
gfn);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic);
 
 kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
 {
-       return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn);
+       return gfn_to_pfn_memslot(kvm, gfn_to_memslot(kvm, gfn), gfn);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn);
 
 kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
-       return gfn_to_pfn_memslot(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
+       return gfn_to_pfn_memslot(vcpu->kvm,
+                                 kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn);
 
@@ -2115,18 +2123,20 @@ void kvm_release_pfn(kvm_pfn_t pfn, bool dirty, struct 
gfn_to_pfn_cache *cache)
                kvm_release_pfn_clean(pfn);
 }
 
-static void kvm_cache_gfn_to_pfn(struct kvm_memory_slot *slot, gfn_t gfn,
+static void kvm_cache_gfn_to_pfn(struct kvm *kvm,
+                                struct kvm_memory_slot *slot, gfn_t gfn,
                                 struct gfn_to_pfn_cache *cache, u64 gen)
 {
        kvm_release_pfn(cache->pfn, cache->dirty, cache);
 
-       cache->pfn = gfn_to_pfn_memslot(slot, gfn);
+       cache->pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
        cache->gfn = gfn;
        cache->dirty = false;
        cache->generation = gen;
 }
 
-static int __kvm_map_gfn(struct kvm_memslots *slots, gfn_t gfn,
+static int __kvm_map_gfn(struct kvm *kvm,
+                        struct kvm_memslots *slots, gfn_t gfn,
                         struct kvm_host_map *map,
                         struct gfn_to_pfn_cache *cache,
                         bool atomic)
@@ -2145,13 +2155,13 @@ static int __kvm_map_gfn(struct kvm_memslots *slots, 
gfn_t gfn,
                        cache->generation != gen) {
                        if (atomic)
                                return -EAGAIN;
-                       kvm_cache_gfn_to_pfn(slot, gfn, cache, gen);
+                       kvm_cache_gfn_to_pfn(kvm, slot, gfn, cache, gen);
                }
                pfn = cache->pfn;
        } else {
                if (atomic)
                        return -EAGAIN;
-               pfn = gfn_to_pfn_memslot(slot, gfn);
+               pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
        }
        if (is_error_noslot_pfn(pfn))
                return -EINVAL;
@@ -2184,14 +2194,14 @@ static int __kvm_map_gfn(struct kvm_memslots *slots, 
gfn_t gfn,
 int kvm_map_gfn(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
                struct gfn_to_pfn_cache *cache, bool atomic)
 {
-       return __kvm_map_gfn(kvm_memslots(vcpu->kvm), gfn, map,
+       return __kvm_map_gfn(vcpu->kvm, kvm_memslots(vcpu->kvm), gfn, map,
                        cache, atomic);
 }
 EXPORT_SYMBOL_GPL(kvm_map_gfn);
 
 int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
 {
-       return __kvm_map_gfn(kvm_vcpu_memslots(vcpu), gfn, map,
+       return __kvm_map_gfn(vcpu->kvm, kvm_vcpu_memslots(vcpu), gfn, map,
                NULL, false);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_map);
-- 
2.29.2

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