hw/pvrdma: Protect against buggy or malicious guest driver

hw/pvrdma: Protect against buggy or malicious guest driver

Guest driver allocates and initialize page tables to be used as a ring
of descriptors for CQ and async events.
The page table that represents the ring, along with the number of pages
in the page table is passed to the device.
Currently our device supports only one page table for a ring.

Let's make sure that the number of page table entries the driver
reports, do not exceeds the one page table size.

Reported-by: Soul Chen <soulchen8650@gmail.com>
Signed-off-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
Fixes: CVE-2023-1544
Message-ID: <20230301142926.18686-1-yuval.shaia.ml@gmail.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>