KVM: Introduce kvm_host_page_size

This patch introduces a generic function to find out the
host page size for a given gfn. This function is needed by
the kvm iommu code. This patch also simplifies the x86
host_mapping_level function.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

3 files changed, 28 insertions, 16 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index dc4d954efacd..913ef4b7939a 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -468,24 +468,10 @@ static int has_wrprotected_page(struct kvm *kvm,
 
 static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
 {
-        unsigned long page_size = PAGE_SIZE;
-        struct vm_area_struct *vma;
-        unsigned long addr;
+        unsigned long page_size;
         int i, ret = 0;
 
-        addr = gfn_to_hva(kvm, gfn);
-        if (kvm_is_error_hva(addr))
-                return PT_PAGE_TABLE_LEVEL;
-
-        down_read(&current->mm->mmap_sem);
-        vma = find_vma(current->mm, addr);
-        if (!vma)
-                goto out;
-
-        page_size = vma_kernel_pagesize(vma);
-
-out:
-        up_read(&current->mm->mmap_sem);
+        page_size = kvm_host_page_size(kvm, gfn);
 
         for (i = PT_PAGE_TABLE_LEVEL;
              i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 665c37063f30..3145b281de9d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -300,6 +300,7 @@ int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len);
 int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len);
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn);
 int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn);
+unsigned long kvm_host_page_size(struct kvm *kvm, gfn_t gfn);
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
 
 void kvm_vcpu_block(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2b0974a14835..0a360c26cc34 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -45,6 +45,7 @@
 #include <linux/spinlock.h>
 #include <linux/compat.h>
 #include <linux/srcu.h>
+#include <linux/hugetlb.h>
 
 #include <asm/processor.h>
 #include <asm/io.h>
@@ -867,6 +868,30 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
 
+unsigned long kvm_host_page_size(struct kvm *kvm, gfn_t gfn)
+{
+        struct vm_area_struct *vma;
+        unsigned long addr, size;
+
+        size = PAGE_SIZE;
+
+        addr = gfn_to_hva(kvm, gfn);
+        if (kvm_is_error_hva(addr))
+                return PAGE_SIZE;
+
+        down_read(&current->mm->mmap_sem);
+        vma = find_vma(current->mm, addr);
+        if (!vma)
+                goto out;
+
+        size = vma_kernel_pagesize(vma);
+
+out:
+        up_read(&current->mm->mmap_sem);
+
+        return size;
+}
+
 int memslot_id(struct kvm *kvm, gfn_t gfn)
 {
         int i;