Commit 1eff70a9 authored by Boris Ostrovsky's avatar Boris Ostrovsky Committed by Paolo Bonzini
Browse files

x86/kvm: Introduce kvm_(un)map_gfn() 



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: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJoao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8c6de56a

include/linux/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -775,8 +775,10 @@ struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn 
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,

virt/kvm/kvm_main.c

+24 −5
Original line number Diff line number Diff line
@@ -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)

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