[PATCH v7 16/17] kvm: pass kvm argument to follow_pfn callsites

From: Daniel Vetter
Date: Fri Nov 27 2020 - 11:42:55 EST

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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.

Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-samsung-soc@xxxxxxxxxxxxxxx
Cc: linux-media@xxxxxxxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
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 5bb1939b65d8..67ada47aa722 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2679,7 +2679,7 @@ 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,
@@ -3657,7 +3657,8 @@ 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 */

@@ -3671,7 +3672,8 @@ 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

Next message: Daniel Vetter: "[PATCH v7 14/17] media/videobuf1|2: Mark follow_pfn usage as unsafe"
Previous message: Daniel Vetter: "[PATCH v7 13/17] mm: Add unsafe_follow_pfn"
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