From: Boris Ostrovsky boris.ostrovsky@oracle.com

kvm_vcpu_(un)map operates on gfns from any current address space. In certain cases we want to make sure we are not mapping SMRAM and for that we can use kvm_(un)map_gfn() that we are introducing in this patch.

This is part of CVE-2019-3016.

Signed-off-by: Boris Ostrovsky boris.ostrovsky@oracle.com Reviewed-by: Joao Martins joao.m.martins@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 29 ++++++++++++++++++++++++----- 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 538c25e..0cb78f5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -775,8 +775,10 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn); kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn); int kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_host_map *map); +int kvm_map_gfn(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map); struct page *kvm_vcpu_gfn_to_page(struct kvm_vcpu *vcpu, gfn_t gfn); void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty); +int kvm_unmap_gfn(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty); unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn); unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable); int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data, int offset, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 0026829..9ef58a2 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1821,12 +1821,13 @@ struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn) } EXPORT_SYMBOL_GPL(gfn_to_page);

-static int __kvm_map_gfn(struct kvm_memory_slot *slot, gfn_t gfn, +static int __kvm_map_gfn(struct kvm_memslots *slots, gfn_t gfn, struct kvm_host_map *map) { kvm_pfn_t pfn; void *hva = NULL; struct page *page = KVM_UNMAPPED_PAGE; + struct kvm_memory_slot *slot = __gfn_to_memslot(slots, gfn);

if (!map) return -EINVAL; @@ -1855,14 +1856,20 @@ static int __kvm_map_gfn(struct kvm_memory_slot *slot, gfn_t gfn, return 0; }

+int kvm_map_gfn(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map) +{ + return __kvm_map_gfn(kvm_memslots(vcpu->kvm), gfn, map); +} +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_gfn_to_memslot(vcpu, gfn), gfn, map); + return __kvm_map_gfn(kvm_vcpu_memslots(vcpu), gfn, map); } EXPORT_SYMBOL_GPL(kvm_vcpu_map);

-void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, - bool dirty) +static void __kvm_unmap_gfn(struct kvm_memory_slot *memslot, + struct kvm_host_map *map, bool dirty) { if (!map) return; @@ -1878,7 +1885,7 @@ void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, #endif

if (dirty) { - kvm_vcpu_mark_page_dirty(vcpu, map->gfn); + mark_page_dirty_in_slot(memslot, map->gfn); kvm_release_pfn_dirty(map->pfn); } else { kvm_release_pfn_clean(map->pfn); @@ -1887,6 +1894,18 @@ void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, map->hva = NULL; map->page = NULL; } + +int kvm_unmap_gfn(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty) +{ + __kvm_unmap_gfn(gfn_to_memslot(vcpu->kvm, map->gfn), map, dirty); + return 0; +} +EXPORT_SYMBOL_GPL(kvm_unmap_gfn); + +void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty) +{ + __kvm_unmap_gfn(kvm_vcpu_gfn_to_memslot(vcpu, map->gfn), map, dirty); +} EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);

struct page *kvm_vcpu_gfn_to_page(struct kvm_vcpu *vcpu, gfn_t gfn)