[PATCH v2 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall
Marc Zyngier
maz at kernel.org
Mon Jan 4 08:50:10 EST 2021
For completeness, let's document the HVC_VHE_RESTART stub.
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
Documentation/virt/kvm/arm/hyp-abi.rst | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/Documentation/virt/kvm/arm/hyp-abi.rst b/Documentation/virt/kvm/arm/hyp-abi.rst
index 83cadd8186fa..3961c529769b 100644
--- a/Documentation/virt/kvm/arm/hyp-abi.rst
+++ b/Documentation/virt/kvm/arm/hyp-abi.rst
@@ -58,6 +58,15 @@ these functions (see arch/arm{,64}/include/asm/virt.h):
into place (arm64 only), and jump to the restart address while at HYP/EL2.
This hypercall is not expected to return to its caller.
+* ::
+
+ x0 = HVC_VHE_RESTART (arm64 only)
+
+ Attempt to upgrade the kernel's exception level from EL1 to EL2 by enabling
+ the VHE mode. This is conditionned by the CPU supporting VHE, the EL2 MMU
+ being off, and VHE not being disabled by any other mean (comment line option,
+ for example).
+
Any other value of r0/x0 triggers a hypervisor-specific handling,
which is not documented here.
--
2.29.2
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