CVE ID:	CVE-2023-52455
Description:	In the Linux kernel, the following vulnerability has been resolved: iommu: Don't reserve 0-length IOVA region When the bootloader/firmware doesn't setup the framebuffers, their address and size are 0 in "iommu-addresses" property. If IOVA region is reserved with 0 length, then it ends up corrupting the IOVA rbtree with an entry which has pfn_hi < pfn_lo. If we intend to use display driver in kernel without framebuffer then it's causing the display IOMMU mappings to fail as entire valid IOVA space is reserved when address and length are passed as 0. An ideal solution would be firmware removing the "iommu- addresses" property and corresponding "memory-region" if display is not present. But the kernel should be able to handle this by checking for size of IOVA region and skipping the IOVA reservation if size is 0. Also, add a warning if firmware is requesting 0-length IOVA region reservation.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2023-52455 https://git.kernel.org/stable/c/5e23e283910c9f30248732ae0770bcb0c9438abf https://git.kernel.org/stable/c/5e23e283910c9f30248732ae0770bcb0c9438abf https://git.kernel.org/stable/c/98b8a550da83cc392a14298c4b3eaaf0332ae6ad https://git.kernel.org/stable/c/98b8a550da83cc392a14298c4b3eaaf0332ae6ad https://git.kernel.org/stable/c/bb57f6705960bebeb832142ce9abf43220c3eab1 https://git.kernel.org/stable/c/bb57f6705960bebeb832142ce9abf43220c3eab1