Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[platform/kernel/linux-rpi.git] / arch / arm64 / kernel / fpsimd.c

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index f2307d6..5280e09 100644 (file)
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -79,7 +79,11 @@
  * indicate whether or not the userland FPSIMD state of the current task is
  * present in the registers. The flag is set unless the FPSIMD registers of this
  * CPU currently contain the most recent userland FPSIMD state of the current
- * task.
+ * task. If the task is behaving as a VMM, then this is will be managed by
+ * KVM which will clear it to indicate that the vcpu FPSIMD state is currently
+ * loaded on the CPU, allowing the state to be saved if a FPSIMD-aware
+ * softirq kicks in. Upon vcpu_put(), KVM will save the vcpu FP state and
+ * flag the register state as invalid.
  *
  * In order to allow softirq handlers to use FPSIMD, kernel_neon_begin() may
  * save the task's FPSIMD context back to task_struct from softirq context.