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[v3] Documentation: Update the behaviour of "kvm-arm.mode"

Message ID 20241025093259.2216093-1-smostafa@google.com (mailing list archive)
State New
Headers show
Series [v3] Documentation: Update the behaviour of "kvm-arm.mode" | expand

Commit Message

Mostafa Saleh Oct. 25, 2024, 9:32 a.m. UTC 
Commit 5053c3f0519c ("KVM: arm64: Use hVHE in pKVM by default on CPUs with
VHE support") modified the behaviour of "kvm-arm.mode=protected" without
the updating the kernel parameters doc.

Update it to match the current implementation.

Also, update required architecture version for nested virtualization as
suggested by Marc.

Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>

Signed-off-by: Mostafa Saleh <smostafa@google.com>

---
v3: Reword as Marc suggested.

v2: Update nested value also
---
 Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)
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Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1518343bbe22..ed92e207e9a0 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2740,17 +2740,21 @@ 
 			nvhe: Standard nVHE-based mode, without support for
 			      protected guests.
 
-			protected: nVHE-based mode with support for guests whose
-				   state is kept private from the host.
+			protected: Mode with support for guests whose state is
+				   kept private from the host, using VHE or
+				   nVHE depending on HW support.
 
 			nested: VHE-based mode with support for nested
-				virtualization. Requires at least ARMv8.3
-				hardware.
+				virtualization. Requires at least ARMv8.4
+				hardware (with FEAT_NV2).
 
 			Defaults to VHE/nVHE based on hardware support. Setting
 			mode to "protected" will disable kexec and hibernation
-			for the host. "nested" is experimental and should be
-			used with extreme caution.
+			for the host. To force nVHE on VHE hardware, add
+			"arm64_sw.hvhe=0 id_aa64mmfr1.vh=0" to the
+			command-line.
+			"nested" is experimental and should be used with
+			extreme caution.
 
 	kvm-arm.vgic_v3_group0_trap=
 			[KVM,ARM,EARLY] Trap guest accesses to GICv3 group-0