KVM: MMU: introduce gfn_to_page_many_atomic() function
Introduce this function to get consecutive gfn's pages, it can reduce
gup's overload, used by later patch
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 307d0e2..b837ec8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -289,6 +289,9 @@
void kvm_disable_largepages(void);
void kvm_arch_flush_shadow(struct kvm *kvm);
+int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages,
+ int nr_pages);
+
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
void kvm_release_page_clean(struct page *page);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 08bd304..2eb0b75 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -927,15 +927,25 @@
return memslot - slots->memslots;
}
-unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
+static unsigned long gfn_to_hva_many(struct kvm *kvm, gfn_t gfn,
+ gfn_t *nr_pages)
{
struct kvm_memory_slot *slot;
slot = gfn_to_memslot(kvm, gfn);
if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
return bad_hva();
+
+ if (nr_pages)
+ *nr_pages = slot->npages - (gfn - slot->base_gfn);
+
return gfn_to_hva_memslot(slot, gfn);
}
+
+unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
+{
+ return gfn_to_hva_many(kvm, gfn, NULL);
+}
EXPORT_SYMBOL_GPL(gfn_to_hva);
static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic)
@@ -1010,6 +1020,23 @@
return hva_to_pfn(kvm, addr, false);
}
+int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages,
+ int nr_pages)
+{
+ unsigned long addr;
+ gfn_t entry;
+
+ addr = gfn_to_hva_many(kvm, gfn, &entry);
+ if (kvm_is_error_hva(addr))
+ return -1;
+
+ if (entry < nr_pages)
+ return 0;
+
+ return __get_user_pages_fast(addr, nr_pages, 1, pages);
+}
+EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
+
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
{
pfn_t pfn;
