[xen staging] pdx: move some helpers in preparation for new compression

[patchbot@xxxxxxx]

commit 353e5952943fe03bb0866243132333dace700ff1
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Tue Jun 17 16:35:13 2025 +0200
Commit:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
CommitDate: Mon Aug 11 18:45:52 2025 +0200

    pdx: move some helpers in preparation for new compression
    
    Move fill_mask(), pdx_region_mask() and pdx_init_mask() to the
    !CONFIG_PDX_NONE section in preparation of them also being used by a newly
    added PDX compression.
    
    No functional change intended.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/common/pdx.c | 118 +++++++++++++++++++++++++++----------------------------
 1 file changed, 59 insertions(+), 59 deletions(-)

diff --git a/xen/common/pdx.c b/xen/common/pdx.c
index cd8a9e75a8..9e6b36086f 100644
--- a/xen/common/pdx.c
+++ b/xen/common/pdx.c
@@ -101,59 +101,6 @@ void __init pfn_pdx_add_region(paddr_t base, paddr_t size)
     ranges[nr_ranges++].pages = PFN_UP(base + size) - PFN_DOWN(base);
 }
 
-#endif /* !CONFIG_PDX_NONE */
-
-#ifdef CONFIG_PDX_MASK_COMPRESSION
-
-/*
- * Diagram to make sense of the following variables. The masks and shifts
- * are done on mfn values in order to convert to/from pdx:
- *
- *                      pfn_hole_mask
- *                      pfn_pdx_hole_shift (mask bitsize)
- *                      |
- *                 |---------|
- *                 |         |
- *                 V         V
- *         --------------------------
- *         |HHHHHHH|000000000|LLLLLL| <--- mfn
- *         --------------------------
- *         ^       ^         ^      ^
- *         |       |         |------|
- *         |       |             |
- *         |       |             pfn_pdx_bottom_mask
- *         |       |
- *         |-------|
- *             |
- *             pfn_top_mask
- *
- * ma_{top,va_bottom}_mask is simply a shifted pfn_{top,pdx_bottom}_mask,
- * where ma_top_mask has zeroes shifted in while ma_va_bottom_mask has
- * ones.
- */
-
-/** Mask for the lower non-compressible bits of an mfn */
-unsigned long __ro_after_init pfn_pdx_bottom_mask = ~0UL;
-
-/** Mask for the lower non-compressible bits of an maddr or vaddr */
-unsigned long __ro_after_init ma_va_bottom_mask = ~0UL;
-
-/** Mask for the higher non-compressible bits of an mfn */
-unsigned long __ro_after_init pfn_top_mask = 0;
-
-/** Mask for the higher non-compressible bits of an maddr or vaddr */
-unsigned long __ro_after_init ma_top_mask = 0;
-
-/**
- * Mask for a pdx compression bit slice.
- *
- *  Invariant: valid(mfn) implies (mfn & pfn_hole_mask) == 0
- */
-unsigned long __ro_after_init pfn_hole_mask = 0;
-
-/** Number of bits of the "compressible" bit slice of an mfn */
-unsigned int __ro_after_init pfn_pdx_hole_shift = 0;
-
 /* Sets all bits from the most-significant 1-bit down to the LSB */
 static uint64_t fill_mask(uint64_t mask)
 {
@@ -196,12 +143,6 @@ static uint64_t pdx_region_mask(uint64_t base, uint64_t 
len)
     return fill_mask(base ^ (base + len - 1));
 }
 
-bool pdx_is_region_compressible(paddr_t base, unsigned long npages)
-{
-    return !(paddr_to_pfn(base) & pfn_hole_mask) &&
-           !(pdx_region_mask(base, npages * PAGE_SIZE) & ~ma_va_bottom_mask);
-}
-
 /**
  * Creates the mask to start from when calculating non-compressible bits
  *
@@ -219,6 +160,65 @@ static uint64_t __init pdx_init_mask(uint64_t base_addr)
                          (uint64_t)1 << (MAX_ORDER + PAGE_SHIFT)) - 1);
 }
 
+#endif /* !CONFIG_PDX_NONE */
+
+#ifdef CONFIG_PDX_MASK_COMPRESSION
+
+/*
+ * Diagram to make sense of the following variables. The masks and shifts
+ * are done on mfn values in order to convert to/from pdx:
+ *
+ *                      pfn_hole_mask
+ *                      pfn_pdx_hole_shift (mask bitsize)
+ *                      |
+ *                 |---------|
+ *                 |         |
+ *                 V         V
+ *         --------------------------
+ *         |HHHHHHH|000000000|LLLLLL| <--- mfn
+ *         --------------------------
+ *         ^       ^         ^      ^
+ *         |       |         |------|
+ *         |       |             |
+ *         |       |             pfn_pdx_bottom_mask
+ *         |       |
+ *         |-------|
+ *             |
+ *             pfn_top_mask
+ *
+ * ma_{top,va_bottom}_mask is simply a shifted pfn_{top,pdx_bottom}_mask,
+ * where ma_top_mask has zeroes shifted in while ma_va_bottom_mask has
+ * ones.
+ */
+
+/** Mask for the lower non-compressible bits of an mfn */
+unsigned long __ro_after_init pfn_pdx_bottom_mask = ~0UL;
+
+/** Mask for the lower non-compressible bits of an maddr or vaddr */
+unsigned long __ro_after_init ma_va_bottom_mask = ~0UL;
+
+/** Mask for the higher non-compressible bits of an mfn */
+unsigned long __ro_after_init pfn_top_mask = 0;
+
+/** Mask for the higher non-compressible bits of an maddr or vaddr */
+unsigned long __ro_after_init ma_top_mask = 0;
+
+/**
+ * Mask for a pdx compression bit slice.
+ *
+ *  Invariant: valid(mfn) implies (mfn & pfn_hole_mask) == 0
+ */
+unsigned long __ro_after_init pfn_hole_mask = 0;
+
+/** Number of bits of the "compressible" bit slice of an mfn */
+unsigned int __ro_after_init pfn_pdx_hole_shift = 0;
+
+bool pdx_is_region_compressible(paddr_t base, unsigned long npages)
+{
+    return !(paddr_to_pfn(base) & pfn_hole_mask) &&
+           !(pdx_region_mask(base, npages * PAGE_SIZE) & ~ma_va_bottom_mask);
+}
+
 bool __init pfn_pdx_compression_setup(paddr_t base)
 {
     unsigned int i, j, bottom_shift = 0, hole_shift = 0;
--
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