xen: allow privcmd for HVM guests

This patch removes the "return -ENOSYS" for auto_translated_physmap
guests from privcmd_mmap, thus it allows ARM guests to issue privcmd
mmap calls. However privcmd mmap calls are still going to fail for HVM
and hybrid guests on x86 because the xen_remap_domain_mfn_range
implementation is currently PV only.

Changes in v2:

- better commit message;
- return -EINVAL from xen_remap_domain_mfn_range if
  auto_translated_physmap.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

2 files changed, 3 insertions, 4 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 3a73785631ce..885a22354a96 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2310,6 +2310,9 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
         unsigned long range;
         int err = 0;
 
+        if (xen_feature(XENFEAT_auto_translated_physmap))
+                return -EINVAL;
+
         prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
 
         BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) ==
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index ccee0f16bcf8..85226cbeca24 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -380,10 +380,6 @@ static struct vm_operations_struct privcmd_vm_ops = {
 
 static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
 {
-        /* Unsupported for auto-translate guests. */
-        if (xen_feature(XENFEAT_auto_translated_physmap))
-                return -ENOSYS;
-
         /* DONTCOPY is essential for Xen because copy_page_range doesn't know
          * how to recreate these mappings */
         vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY | VM_PFNMAP;