exec-all.h: Document tlb_set_page_with_attrs, tlb_set_page

Add documentation comments for tlb_set_page_with_attrs()
and tlb_set_page().

Backports commit 1787cc8ee55143b6071c87e59f08d56e7c22c1eb from qemu

qemu/include/exec/exec-all.h

@@ -145,12 +145,40 @@ void tlb_flush_page_by_mmuidx(CPUState *cpu, target_ulong addr, ...);
  * MMU indexes.
  */
 void tlb_flush_by_mmuidx(CPUState *cpu, ...);
-void tlb_set_page(CPUState *cpu, target_ulong vaddr,
+/**
-                  hwaddr paddr, int prot,
+ * tlb_set_page_with_attrs:
-                  int mmu_idx, target_ulong size);
+ * @cpu: CPU to add this TLB entry for
+ * @vaddr: virtual address of page to add entry for
+ * @paddr: physical address of the page
+ * @attrs: memory transaction attributes
+ * @prot: access permissions (PAGE_READ/PAGE_WRITE/PAGE_EXEC bits)
+ * @mmu_idx: MMU index to insert TLB entry for
+ * @size: size of the page in bytes
+ *
+ * Add an entry to this CPU's TLB (a mapping from virtual address
+ * @vaddr to physical address @paddr) with the specified memory
+ * transaction attributes. This is generally called by the target CPU
+ * specific code after it has been called through the tlb_fill()
+ * entry point and performed a successful page table walk to find
+ * the physical address and attributes for the virtual address
+ * which provoked the TLB miss.
+ *
+ * At most one entry for a given virtual address is permitted. Only a
+ * single TARGET_PAGE_SIZE region is mapped; the supplied @size is only
+ * used by tlb_flush_page.
+ */
 void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
                              hwaddr paddr, MemTxAttrs attrs,
                              int prot, int mmu_idx, target_ulong size);
+/* tlb_set_page:
+ *
+ * This function is equivalent to calling tlb_set_page_with_attrs()
+ * with an @attrs argument of MEMTXATTRS_UNSPECIFIED. It's provided
+ * as a convenience for CPUs which don't use memory transaction attributes.
+ */
+void tlb_set_page(CPUState *cpu, target_ulong vaddr,
+                  hwaddr paddr, int prot,
+                  int mmu_idx, target_ulong size);
 
 void tb_invalidate_phys_addr(AddressSpace *as, hwaddr addr);