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[14/14] KVM: arm64: Document NV caps and vcpu flags

Message ID 20250215173816.3767330-15-maz@kernel.org (mailing list archive)
State New
Headers show
Series KVM: arm64: NV userspace ABI | expand

Commit Message

Marc Zyngier Feb. 15, 2025, 5:38 p.m. UTC 
Describe the two new vcpu flags that control NV, together with
the capabilities that advertise them.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 Documentation/virt/kvm/api.rst | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Oliver Upton Feb. 19, 2025, 11:19 p.m. UTC | #1 
On Sat, Feb 15, 2025 at 05:38:16PM +0000, Marc Zyngier wrote:
> Describe the two new vcpu flags that control NV, together with
> the capabilities that advertise them.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

Thanks,
Oliver
diff mbox series

Patch

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 2b52eb77e29cb..2d7b516ae408d 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -3456,7 +3456,8 @@  The initial values are defined as:
 	- 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)
+	  values as for a warm reset to EL1 (resp. SVC) or EL2 (in the
+	  case of EL2 being enabled).
 
 Note that because some registers reflect machine topology, all vcpus
 should be created before this ioctl is invoked.
@@ -3523,6 +3524,17 @@  Possible features:
 	      - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can
 	        no longer be written using KVM_SET_ONE_REG.
 
+	- KVM_ARM_VCPU_HAS_EL2: Enable Nested Virtualisation support,
+	  booting the guest from EL2 instead of EL1.
+	  Depends on KVM_CAP_ARM_EL2.
+	  The VM is running with HCR_EL2.E2H being RES1 (VHE) unless
+	  KVM_ARM_VCPU_HAS_EL2_E2H0 is also set.
+
+	- KVM_ARM_VCPU_HAS_EL2_E2H0: Restrict Nested Virtualisation
+	  support to HCR_EL2.E2H being RES0 (non-VHE).
+	  Depends on KVM_CAP_ARM_EL2_E2H0.
+	  KVM_ARM_VCPU_HAS_EL2 must also be set.
+
 4.83 KVM_ARM_PREFERRED_TARGET
 -----------------------------