Oliver Upton efa1368ba9 KVM: arm64: Commit exceptions from KVM_SET_VCPU_EVENTS immediately
syzkaller has found that it can trip a warning in KVM's exception
emulation infrastructure by repeatedly injecting exceptions into the
guest.

While it's unlikely that a reasonable VMM will do this, further
investigation of the issue reveals that KVM can potentially discard the
"pending" SEA state. While the handling of KVM_GET_VCPU_EVENTS presumes
that userspace-injected SEAs are realized immediately, in reality the
emulated exception entry is deferred until the next call to KVM_RUN.

Hack-a-fix the immediate issues by committing the pending exceptions to
the vCPU's architectural state immediately in KVM_SET_VCPU_EVENTS. This
is no different to the way KVM-injected exceptions are handled in
KVM_RUN where we potentially call __kvm_adjust_pc() before returning to
userspace.

Reported-by: syzbot+4e09b1432de3774b86ae@syzkaller.appspotmail.com
Reported-by: syzbot+1f6f096afda6f4f8f565@syzkaller.appspotmail.com
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-15 20:12:03 -07:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-06-22 13:30:08 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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