During trace remote loading, hyp_trace_load() allocates the descriptor
pages but fails to store the allocated size in trace_buffer->desc_size.
As a result, when unloading the trace buffer, hyp_trace_unload() calls
free_pages_exact() with a size of 0 which fails to free the memory.
Fix this by updating the descriptor size in trace_buffer->desc_size.
Fixes: 3aed038aac ("KVM: arm64: Add trace remote for the nVHE/pKVM hyp")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260521124613.911067-4-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
When sharing the trace buffer with the hypervisor, if sharing a page
fails, the rollback path in hyp_trace_buffer_share_hyp() misses
unsharing the metadata page (meta_va) which was successfully shared
before entering the page sharing loop.
Additionally, if a failure occurs, the cleanup calls
hyp_trace_buffer_unshare_hyp() with an incorrect CPU index. Since that
CPU's pages were already rolled back locally in the loop, this leads to
duplicate unsharing attempts.
Fix both issues affecting the rollback.
Fixes: 3aed038aac ("KVM: arm64: Add trace remote for the nVHE/pKVM hyp")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260521124613.911067-3-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
As the hyp_trace_buffer_unshare_hyp() function name suggests we should
unshare all the previously shared pages, otherwise we leak hyp-shared
pages which won't be reusable for hyp memory.
Fix the typo by calling __unshare_page() on the meta-page, ensuring all
previously shared pages are correctly unshared.
Fixes: 3aed038aac ("KVM: arm64: Add trace remote for the nVHE/pKVM hyp")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260521124613.911067-2-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
The 'cpu' variable is only used inside of an #ifdef block and causes
a warning if there is no user:
arch/arm64/kvm/hyp_trace.c: In function 'kvm_hyp_trace_init':
arch/arm64/kvm/hyp_trace.c:422:13: error: unused variable 'cpu' [-Werror=unused-variable]
422 | int cpu;
| ^~~
Change the #ifdef to an equivalent IS_ENABLED() check to avoid
the warning.
Fixes: b22888917f ("KVM: arm64: Sync boot clock with the nVHE/pKVM hyp")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260313094925.3749287-1-arnd@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Add a selftest event that can be triggered from a `write_event` tracefs
file. This intends to be used by trace remote selftests.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-30-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Allow the creation of hypervisor and trace remote events with a single
macro HYP_EVENT(). That macro expands in the kernel side to add all
the required declarations (based on REMOTE_EVENT()) as well as in the
hypervisor side to create the trace_<event>() function.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-28-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Make the hypervisor reset either the whole tracing buffer or a specific
ring-buffer, on remotes/hypervisor/trace or per_cpu/<cpu>/trace write
access.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-27-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Configure the hypervisor tracing clock with the kernel boot clock. For
tracing purposes, the boot clock is interesting: it doesn't stop on
suspend. However, it is corrected on a regular basis, which implies the
need to re-evaluate it every once in a while.
Cc: John Stultz <jstultz@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-26-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
In both protected and nVHE mode, the hypervisor is capable of writing
events into tracefs compatible ring-buffers. Create a trace remote so
the kernel can read those buffers.
This currently doesn't provide any event support which will come later.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-25-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
