From: Quentin Perret <qperret@xxxxxxxxxx>
The host KVM PMU code can currently index kvm_arm_hyp_percpu_base[]
through this_cpu_ptr_hyp_sym(), but will not actually dereference that
pointer when protected KVM is enabled. In preparation for making
kvm_arm_hyp_percpu_base[] unaccessible to the host, let's make sure the
indexing in hyp per-cpu pages is also done after the static key check to
avoid spurious accesses to EL2-private data from EL1.
Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
---
arch/arm64/kvm/pmu.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 03a6c1f4a09a..a8878fd8b696 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -31,9 +31,13 @@ static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)
*/
void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
{
- struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+ struct kvm_host_data *ctx;
- if (!kvm_arm_support_pmu_v3() || !ctx || !kvm_pmu_switch_needed(attr))
+ if (!kvm_arm_support_pmu_v3())
+ return;
+
+ ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+ if (!ctx || !kvm_pmu_switch_needed(attr))
return;
if (!attr->exclude_host)
@@ -47,9 +51,13 @@ void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
*/
void kvm_clr_pmu_events(u32 clr)
{
- struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+ struct kvm_host_data *ctx;
+
+ if (!kvm_arm_support_pmu_v3())
+ return;
- if (!kvm_arm_support_pmu_v3() || !ctx)
+ ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
+ if (!ctx)
return;
ctx->pmu_events.events_host &= ~clr;
--
2.36.1.124.g0e6072fb45-goog
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