x86/mm: move mmio_ro_emulated_write() to PV only file

mmio_ro_emulated_write() is only used in pv/ro-page-fault.c, move the
function to that file and make it static.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/include/asm/mm.h

@@ -542,18 +542,6 @@ void memguard_unguard_stack(void *p);
 int subpage_mmio_ro_add(paddr_t start, size_t size);
 bool subpage_mmio_write_accept(mfn_t mfn, unsigned long gla);
 
-struct mmio_ro_emulate_ctxt {
-        unsigned long cr2;
-        /* Used only for mmcfg case */
-        unsigned int seg, bdf;
-        /* Used only for non-mmcfg case */
-        mfn_t mfn;
-};
-
-int cf_check mmio_ro_emulated_write(
-    enum x86_segment seg, unsigned long offset, void *p_data,
-    unsigned int bytes, struct x86_emulate_ctxt *ctxt);
-
 /* r/o MMIO subpage access handlers. */
 struct subpage_ro_range {
     struct list_head list;

xen/arch/x86/mm.c

@@ -5144,39 +5144,6 @@ void subpage_mmio_write_emulate(
         goto write_ignored;
 }
 
-int cf_check mmio_ro_emulated_write(
-    enum x86_segment seg,
-    unsigned long offset,
-    void *p_data,
-    unsigned int bytes,
-    struct x86_emulate_ctxt *ctxt)
-{
-    struct mmio_ro_emulate_ctxt *mmio_ro_ctxt = ctxt->data;
-    unsigned long data = 0;
-
-    /* Only allow naturally-aligned stores at the original %cr2 address. */
-    if ( ((bytes | offset) & (bytes - 1)) || !bytes ||
-         offset != mmio_ro_ctxt->cr2 )
-    {
-        gdprintk(XENLOG_WARNING, "bad access (cr2=%lx, addr=%lx, bytes=%u)\n",
-                mmio_ro_ctxt->cr2, offset, bytes);
-        return X86EMUL_UNHANDLEABLE;
-    }
-
-    if ( bytes <= sizeof(data) )
-    {
-        memcpy(&data, p_data, bytes);
-        subpage_mmio_write_emulate(mmio_ro_ctxt->mfn, PAGE_OFFSET(offset),
-                                   data, bytes);
-    }
-    else if ( subpage_mmio_find_page(mmio_ro_ctxt->mfn) )
-        gprintk(XENLOG_WARNING,
-                "unsupported %u-byte write to R/O MMIO 0x%"PRI_mfn"%03lx\n",
-                bytes, mfn_x(mmio_ro_ctxt->mfn), PAGE_OFFSET(offset));
-
-    return X86EMUL_OKAY;
-}
-
 /*
  * For these PTE APIs, the caller must follow the alloc-map-unmap-free
  * lifecycle, which means explicitly mapping the PTE pages before accessing

xen/arch/x86/pv/ro-page-fault.c

@@ -298,6 +298,14 @@ static int ptwr_do_page_fault(struct x86_emulate_ctxt *ctxt,
  * fault handling for read-only MMIO pages
  */
 
+struct mmio_ro_emulate_ctxt {
+    unsigned long cr2;
+    /* Used only for mmcfg case */
+    unsigned int seg, bdf;
+    /* Used only for non-mmcfg case */
+    mfn_t mfn;
+};
+
 static int cf_check mmcfg_intercept_write(
     enum x86_segment seg,
     unsigned long offset,
@@ -329,6 +337,39 @@ static int cf_check mmcfg_intercept_write(
     return X86EMUL_OKAY;
 }
 
+int cf_check mmio_ro_emulated_write(
+    enum x86_segment seg,
+    unsigned long offset,
+    void *p_data,
+    unsigned int bytes,
+    struct x86_emulate_ctxt *ctxt)
+{
+    struct mmio_ro_emulate_ctxt *mmio_ro_ctxt = ctxt->data;
+    unsigned long data = 0;
+
+    /* Only allow naturally-aligned stores at the original %cr2 address. */
+    if ( ((bytes | offset) & (bytes - 1)) || !bytes ||
+         offset != mmio_ro_ctxt->cr2 )
+    {
+        gdprintk(XENLOG_WARNING, "bad access (cr2=%lx, addr=%lx, bytes=%u)\n",
+                mmio_ro_ctxt->cr2, offset, bytes);
+        return X86EMUL_UNHANDLEABLE;
+    }
+
+    if ( bytes <= sizeof(data) )
+    {
+        memcpy(&data, p_data, bytes);
+        subpage_mmio_write_emulate(mmio_ro_ctxt->mfn, PAGE_OFFSET(offset),
+                                   data, bytes);
+    }
+    else if ( subpage_mmio_find_page(mmio_ro_ctxt->mfn) )
+        gprintk(XENLOG_WARNING,
+                "unsupported %u-byte write to R/O MMIO 0x%"PRI_mfn"%03lx\n",
+                bytes, mfn_x(mmio_ro_ctxt->mfn), PAGE_OFFSET(offset));
+
+    return X86EMUL_OKAY;
+}
+
 static const struct x86_emulate_ops mmio_ro_emulate_ops = {
     .read       = x86emul_unhandleable_rw,
     .insn_fetch = ptwr_emulated_insn_fetch,