CVE-2026-43347: arm64: dts: qcom: monaco: Reserve full Gunyah metadata region

CVE-2026-43347: arm64: dts: qcom: monaco: Reserve full Gunyah metadata region

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

arm64: dts: qcom: monaco: Reserve full Gunyah metadata region

We observe spurious "Synchronous External Abort" exceptions
(ESR=0x96000010) and kernel crashes on Monaco-based platforms.
These faults are caused by the kernel inadvertently accessing
hypervisor-owned memory that is not properly marked as reserved.

>From boot log, The Qualcomm hypervisor reports the memory range
at 0x91a80000 of size 0x80000 (512 KiB) as hypervisor-owned:
qhee_hyp_assign_remove_memory: 0x91a80000/0x80000 -> ret 0

However, the EFI memory map provided by firmware only reserves the
subrange 0x91a40000–0x91a87fff (288 KiB). The remaining portion
(0x91a88000–0x91afffff) is incorrectly reported as conventional
memory (from efi debug):
efi:   0x000091a40000-0x000091a87fff [Reserved...]
efi:   0x000091a88000-0x0000938fffff [Conventional...]

As a result, the allocator may hand out PFNs inside the hypervisor
owned region, causing fatal aborts when the kernel accesses those
addresses.

Add a reserved-memory carveout for the Gunyah hypervisor metadata
at 0x91a80000 (512 KiB) and mark it as no-map so Linux does not
map or allocate from this area.

For the record:
Hyp version: gunyah-e78adb36e debug (2025-11-17 05:38:05 UTC)
UEFI Ver: 6.0.260122.BOOT.MXF.1.0.c1-00449-KODIAKLA-1

The Linux kernel CVE team has assigned CVE-2026-43347 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.14 with commit 7be190e4bdd2bd1aca84afef06bb755c06a85473 and fixed in 6.18.24 with commit edde62571f7602d83243ca51729ce42d22ea04d2
	Issue introduced in 6.14 with commit 7be190e4bdd2bd1aca84afef06bb755c06a85473 and fixed in 6.19.14 with commit 59bd9088336d2bb7e713dcf4df5cbda86bb3c611
	Issue introduced in 6.14 with commit 7be190e4bdd2bd1aca84afef06bb755c06a85473 and fixed in 7.0 with commit 85d98669fa7f1d3041d962515e45ee6e392db6f8

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-43347
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	arch/arm64/boot/dts/qcom/monaco.dtsi


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/edde62571f7602d83243ca51729ce42d22ea04d2
	https://git.kernel.org/stable/c/59bd9088336d2bb7e713dcf4df5cbda86bb3c611
	https://git.kernel.org/stable/c/85d98669fa7f1d3041d962515e45ee6e392db6f8