system: Pass RAM MemoryRegion and is_write in xen_map_cache()

Propagate MR and is_write to xen_map_cache().
This is in preparation for adding support for grant mappings.

No functional change.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-ID: <20240430164939.925307-14-edgar.iglesias@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/xen/xen-mapcache.c

@@ -254,7 +254,7 @@ static void xen_remap_bucket(MapCache *mc,
 
 static uint8_t *xen_map_cache_unlocked(MapCache *mc,
                                        hwaddr phys_addr, hwaddr size,
-                                       uint8_t lock, bool dma)
+                                       uint8_t lock, bool dma, bool is_write)
 {
     MapCacheEntry *entry, *pentry = NULL,
                   *free_entry = NULL, *free_pentry = NULL;
@@ -377,13 +377,15 @@ tryagain:
     return mc->last_entry->vaddr_base + address_offset;
 }
 
-uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size,
-                       uint8_t lock, bool dma)
+uint8_t *xen_map_cache(MemoryRegion *mr,
+                       hwaddr phys_addr, hwaddr size,
+                       uint8_t lock, bool dma,
+                       bool is_write)
 {
     uint8_t *p;
 
     mapcache_lock(mapcache);
-    p = xen_map_cache_unlocked(mapcache, phys_addr, size, lock, dma);
+    p = xen_map_cache_unlocked(mapcache, phys_addr, size, lock, dma, is_write);
     mapcache_unlock(mapcache);
     return p;
 }

include/sysemu/xen-mapcache.h

@@ -18,8 +18,9 @@ typedef hwaddr (*phys_offset_to_gaddr_t)(hwaddr phys_offset,
 
 void xen_map_cache_init(phys_offset_to_gaddr_t f,
                         void *opaque);
-uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size,
-                       uint8_t lock, bool dma);
+uint8_t *xen_map_cache(MemoryRegion *mr, hwaddr phys_addr, hwaddr size,
+                       uint8_t lock, bool dma,
+                       bool is_write);
 ram_addr_t xen_ram_addr_from_mapcache(void *ptr);
 void xen_invalidate_map_cache_entry(uint8_t *buffer);
 void xen_invalidate_map_cache(void);
@@ -33,10 +34,12 @@ static inline void xen_map_cache_init(phys_offset_to_gaddr_t f,
 {
 }
 
-static inline uint8_t *xen_map_cache(hwaddr phys_addr,
+static inline uint8_t *xen_map_cache(MemoryRegion *mr,
+                                     hwaddr phys_addr,
                                      hwaddr size,
                                      uint8_t lock,
-                                     bool dma)
+                                     bool dma,
+                                     bool is_write)
 {
     abort();
 }

system/physmem.c

@@ -2191,11 +2191,22 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
 
 /*
  * Return a host pointer to guest's ram.
+ * For Xen, foreign mappings get created if they don't already exist.
+ *
+ * @block: block for the RAM to lookup (optional and may be NULL).
+ * @addr: address within the memory region.
+ * @size: pointer to requested size (optional and may be NULL).
+ *        size may get modified and return a value smaller than
+ *        what was requested.
+ * @lock: wether to lock the mapping in xen-mapcache until invalidated.
+ * @is_write: hint wether to map RW or RO in the xen-mapcache.
+ *            (optional and may always be set to true).
  *
  * Called within RCU critical section.
  */
 static void *qemu_ram_ptr_length(RAMBlock *block, ram_addr_t addr,
-                                 hwaddr *size, bool lock)
+                                 hwaddr *size, bool lock,
+                                 bool is_write)
 {
     hwaddr len = 0;
 
@@ -2218,10 +2229,13 @@ static void *qemu_ram_ptr_length(RAMBlock *block, ram_addr_t addr,
          * In that case just map the requested area.
          */
         if (block->offset == 0) {
-            return xen_map_cache(addr, len, lock, lock);
+            return xen_map_cache(block->mr, addr, len, lock, lock,
+                                 is_write);
         }
 
-        block->host = xen_map_cache(block->offset, block->max_length, 1, lock);
+        block->host = xen_map_cache(block->mr, block->offset,
+                                    block->max_length, 1,
+                                    lock, is_write);
     }
 
     return ramblock_ptr(block, addr);
@@ -2237,7 +2251,7 @@ static void *qemu_ram_ptr_length(RAMBlock *block, ram_addr_t addr,
  */
 void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr)
 {
-    return qemu_ram_ptr_length(ram_block, addr, NULL, false);
+    return qemu_ram_ptr_length(ram_block, addr, NULL, false, true);
 }
 
 /* Return the offset of a hostpointer within a ramblock */
@@ -2747,7 +2761,7 @@ static MemTxResult flatview_write_continue_step(MemTxAttrs attrs,
     } else {
         /* RAM case */
         uint8_t *ram_ptr = qemu_ram_ptr_length(mr->ram_block, mr_addr, l,
-                                               false);
+                                               false, true);
 
         memmove(ram_ptr, buf, *l);
         invalidate_and_set_dirty(mr, mr_addr, *l);
@@ -2840,7 +2854,7 @@ static MemTxResult flatview_read_continue_step(MemTxAttrs attrs, uint8_t *buf,
     } else {
         /* RAM case */
         uint8_t *ram_ptr = qemu_ram_ptr_length(mr->ram_block, mr_addr, l,
-                                               false);
+                                               false, false);
 
         memcpy(buf, ram_ptr, *l);
 
@@ -3234,7 +3248,7 @@ void *address_space_map(AddressSpace *as,
     *plen = flatview_extend_translation(fv, addr, len, mr, xlat,
                                         l, is_write, attrs);
     fuzz_dma_read_cb(addr, *plen, mr);
-    return qemu_ram_ptr_length(mr->ram_block, xlat, plen, true);
+    return qemu_ram_ptr_length(mr->ram_block, xlat, plen, true, is_write);
 }
 
 /* Unmaps a memory region previously mapped by address_space_map().
@@ -3330,7 +3344,8 @@ int64_t address_space_cache_init(MemoryRegionCache *cache,
         l = flatview_extend_translation(cache->fv, addr, len, mr,
                                         cache->xlat, l, is_write,
                                         MEMTXATTRS_UNSPECIFIED);
-        cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat, &l, true);
+        cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat, &l, true,
+                                         is_write);
     } else {
         cache->ptr = NULL;
     }