Public bug reported:
[Impact]
The ARM-based VM will reboot after executing the 'nvme show-regs' command.
[Fix]
There is an upstream commit that fixed this issue:
commit fa5a46cc25b884a61a14f06e6693373bcefff29d
Author: Oliver Upton <oliver.up...@linux.dev>
Date: Thu Jul 4 19:59:26 2024 +0200
common.h: Avoid using unsupported load/store instructions in arm64
VMs
Using nvme show-regs within a VM on arm64 can sometimes lead to VM
termination.
To answer why this happens: one of the deficiencies of the Arm
architecture is that there exists a range of load/store instructions
that have insufficient decode information for traps taken to the
hypervisor. KVM, for example, may raise an external abort or outright
terminate the VM depending on the configuration.
This is a known problem on the kernel side, and is fixed by using
assembly MMIO accessors w/ 'safe' load/store instructions. So do
exactly that, providing arm64-specific accessors and falling back to
plain old volatile pointer accesses for other architectures.
Reported-by: William Butler <w...@google.com>
Signed-off-by: Oliver Upton <oliver.up...@linux.dev>
[Test Plan]
Execute the command 'nvme show-regs /dev/nvme0' to confirm if it functions
correctly.
[Where problems could occur]
The patch fixes the issue by using assembly code to access MMIO on ARM, while
keeping the original approach on other platforms. If the patch encounters any
issues, it will only impact the functionality of displaying register data on
ARM-based platforms.
** Affects: nvme-cli (Ubuntu)
Importance: Undecided
Status: New
** Affects: nvme-cli (Ubuntu Focal)
Importance: Undecided
Status: New
** Affects: nvme-cli (Ubuntu Jammy)
Importance: Undecided
Status: New
** Affects: nvme-cli (Ubuntu Mantic)
Importance: Undecided
Status: New
** Affects: nvme-cli (Ubuntu Noble)
Importance: Undecided
Status: New
** Affects: nvme-cli (Ubuntu Oracular)
Importance: Undecided
Status: New
** Also affects: nvme-cli (Ubuntu Noble)
Importance: Undecided
Status: New
** Also affects: nvme-cli (Ubuntu Focal)
Importance: Undecided
Status: New
** Also affects: nvme-cli (Ubuntu Mantic)
Importance: Undecided
Status: New
** Also affects: nvme-cli (Ubuntu Jammy)
Importance: Undecided
Status: New
** Also affects: nvme-cli (Ubuntu Oracular)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2072381
Title:
NVMe show-regs command forcibly reboots ARM-based VM
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