KVM: arm64: Clarify vcpu reset behaviour
Although the KVM_ARM_VCPU_INIT documentation mention that the
registers are reset to their "initial values", it doesn't
describe what these values are.
Describe this state explicitly.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 38e327d..fedfe71 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -3115,6 +3115,18 @@
registers to their initial values. If this is not called, KVM_RUN will
return ENOEXEC for that vcpu.
+The initial values are defined as:
+ - Processor state:
+ * AArch64: EL1h, D, A, I and F bits set. All other bits
+ are cleared.
+ * AArch32: SVC, A, I and F bits set. All other bits are
+ cleared.
+ - General Purpose registers, including PC and SP: set to 0
+ - FPSIMD/NEON registers: set to 0
+ - SVE registers: set to 0
+ - System registers: Reset to their architecturally defined
+ values as for a warm reset to EL1 (resp. SVC)
+
Note that because some registers reflect machine topology, all vcpus
should be created before this ioctl is invoked.
