plugins/hotpages: introduce sortby arg and parsed bool args correctly

Since plugin arguments now expect boolean arguments, a plugin argument
name "sortby" now expects a value of "read", "write", or "address".

"io" arg is now expected to be passed as a full-form boolean parameter,
i.e. "io=on|true|yes|off|false|no"

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210730135817.17816-4-ma.mandourr@gmail.com>

docs/devel/tcg-plugins.rst

@@ -193,6 +193,21 @@ Similar to hotblocks but this time tracks memory accesses::
   0x0000000048b000, 0x0001, 130594, 0x0001, 355
   0x0000000048a000, 0x0001, 1826, 0x0001, 11
 
+The hotpages plugin can be configured using the following arguments:
+
+  * sortby=reads|writes|address
+
+  Log the data sorted by either the number of reads, the number of writes, or
+  memory address. (Default: entries are sorted by the sum of reads and writes)
+
+  * io=on
+
+  Track IO addresses. Only relevant to full system emulation. (Default: off)
+
+  * pagesize=N
+
+  The page size used. (Default: N = 4096)
+
 - contrib/plugins/howvec.c
 
 This is an instruction classifier so can be used to count different