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-rw-r--r--include/linux/kvm_host.h28
-rw-r--r--virt/kvm/kvm_main.c64
2 files changed, 92 insertions, 0 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 43f87ad83ff4..6f665c16e31d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -227,6 +227,32 @@ enum {
READING_SHADOW_PAGE_TABLES,
};
+#define KVM_UNMAPPED_PAGE ((void *) 0x500 + POISON_POINTER_DELTA)
+
+struct kvm_host_map {
+ /*
+ * Only valid if the 'pfn' is managed by the host kernel (i.e. There is
+ * a 'struct page' for it. When using mem= kernel parameter some memory
+ * can be used as guest memory but they are not managed by host
+ * kernel).
+ * If 'pfn' is not managed by the host kernel, this field is
+ * initialized to KVM_UNMAPPED_PAGE.
+ */
+ struct page *page;
+ void *hva;
+ kvm_pfn_t pfn;
+ kvm_pfn_t gfn;
+};
+
+/*
+ * Used to check if the mapping is valid or not. Never use 'kvm_host_map'
+ * directly to check for that.
+ */
+static inline bool kvm_vcpu_mapped(struct kvm_host_map *map)
+{
+ return !!map->hva;
+}
+
/*
* Sometimes a large or cross-page mmio needs to be broken up into separate
* exits for userspace servicing.
@@ -733,7 +759,9 @@ struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu);
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);
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);
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 3194aa3d0b43..53de2f946f9e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1742,6 +1742,70 @@ 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,
+ struct kvm_host_map *map)
+{
+ kvm_pfn_t pfn;
+ void *hva = NULL;
+ struct page *page = KVM_UNMAPPED_PAGE;
+
+ if (!map)
+ return -EINVAL;
+
+ pfn = gfn_to_pfn_memslot(slot, gfn);
+ if (is_error_noslot_pfn(pfn))
+ return -EINVAL;
+
+ if (pfn_valid(pfn)) {
+ page = pfn_to_page(pfn);
+ hva = kmap(page);
+ } else {
+ hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
+ }
+
+ if (!hva)
+ return -EFAULT;
+
+ map->page = page;
+ map->hva = hva;
+ map->pfn = pfn;
+ map->gfn = gfn;
+
+ return 0;
+}
+
+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);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_map);
+
+void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map,
+ bool dirty)
+{
+ if (!map)
+ return;
+
+ if (!map->hva)
+ return;
+
+ if (map->page)
+ kunmap(map->page);
+ else
+ memunmap(map->hva);
+
+ if (dirty) {
+ kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
+ kvm_release_pfn_dirty(map->pfn);
+ } else {
+ kvm_release_pfn_clean(map->pfn);
+ }
+
+ map->hva = NULL;
+ map->page = NULL;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
+
struct page *kvm_vcpu_gfn_to_page(struct kvm_vcpu *vcpu, gfn_t gfn)
{
kvm_pfn_t pfn;