[tip: perf/urgent] perf/x86/intel: Make @data a mandatory param for intel_guest_get_msrs()

["tip-bot2 for Sean Christopherson" <tip-bot2@linutronix.de>]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     a391618e1d563f099e4c2a704f45d08329ccdf7c
Gitweb:        https://git.kernel.org/tip/a391618e1d563f099e4c2a704f45d08329ccdf7c
Author:        Sean Christopherson <seanjc@google.com>
AuthorDate:    Mon, 21 Sep 2026 12:14:12 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 22 Sep 2026 11:09:45 +02:00

perf/x86/intel: Make @data a mandatory param for intel_guest_get_msrs()

Drop "support" for passing a NULL @data/@kvm_pmu param when getting guest
MSRs.  KVM, the only in-tree user, unconditionally passes a non-NULL
pointer, and carrying code that suggests @data may be NULL is confusing,
e.g. incorrectly implies that there are scenarios where KVM doesn't pass
a PMU context.

Fixes: 8183a538cd95 ("KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to support guest DS")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://patch.msgid.link/20260921191418.950933-5-seanjc@google.com
---
 arch/x86/events/intel/core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 75c74e8..757d408 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5331,11 +5331,11 @@ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr, void *data)
 	}
 
 	/*
-	 * If the guest won't use PEBS or the CPU doesn't support PEBS in the
-	 * guest, then there's nothing more to do as disabling PMCs via
-	 * PERF_GLOBAL_CTRL is sufficient on CPUs with guest/host isolation.
+	 * If the CPU doesn't support PEBS in the guest, then there's nothing
+	 * more to do as disabling PMCs via PERF_GLOBAL_CTRL is sufficient on
+	 * CPUs with guest/host isolation.
 	 */
-	if (!kvm_pmu || !x86_pmu.pebs_ept)
+	if (!x86_pmu.pebs_ept)
 		return arr;
 
 	/*