[v2,4/4] x86/mm: move mmio_ro_emulated_write() to PV only file

Commit Message

Roger Pau Monné April 15, 2025, 3:32 p.m. UTC

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 <[e-mail]>
Reviewed-by: Jan Beulich <[e-mail]>
---
 xen/arch/x86/include/asm/mm.h   | 12 ------------
 xen/arch/x86/mm.c               | 26 -------------------------
 xen/arch/x86/pv/ro-page-fault.c | 34 +++++++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 38 deletions(-)

Patch

diff --git a/xen/arch/x86/include/asm/mm.h b/xen/arch/x86/include/asm/mm.h
index aeb8ebcf2d56..2665daa6f74f 100644
--- a/xen/arch/x86/include/asm/mm.h
+++ b/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;
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 3bc6304d831c..7c6a5fde5ebd 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5142,32 +5142,6 @@  void subpage_mmio_write_emulate(
     write_mmio(addr + offset, data, len);
 }
 
-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 || bytes > sizeof(data) )
-    {
-        gdprintk(XENLOG_WARNING, "bad access (cr2=%lx, addr=%lx, bytes=%u)\n",
-                mmio_ro_ctxt->cr2, offset, bytes);
-        return X86EMUL_UNHANDLEABLE;
-    }
-
-    memcpy(&data, p_data, bytes);
-    subpage_mmio_write_emulate(mmio_ro_ctxt->mfn, PAGE_OFFSET(offset),
-                               data, bytes);
-
-    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
diff --git a/xen/arch/x86/pv/ro-page-fault.c b/xen/arch/x86/pv/ro-page-fault.c
index 11b01c479e43..3dd795288379 100644
--- a/xen/arch/x86/pv/ro-page-fault.c
+++ b/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 +337,32 @@  static int cf_check mmcfg_intercept_write(
     return X86EMUL_OKAY;
 }
 
+static 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 || bytes > sizeof(data) )
+    {
+        gdprintk(XENLOG_WARNING, "bad access (cr2=%lx, addr=%lx, bytes=%u)\n",
+                mmio_ro_ctxt->cr2, offset, bytes);
+        return X86EMUL_UNHANDLEABLE;
+    }
+
+    memcpy(&data, p_data, bytes);
+    subpage_mmio_write_emulate(mmio_ro_ctxt->mfn, PAGE_OFFSET(offset),
+                               data, bytes);
+
+    return X86EMUL_OKAY;
+}
+
 static const struct x86_emulate_ops mmio_ro_emulate_ops = {
     .read       = x86emul_unhandleable_rw,
     .insn_fetch = ptwr_emulated_insn_fetch,