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FROMGIT: KVM: arm64: Document HVC_VHE_RESTART stub hypercall

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For completeness, let's document the HVC_VHE_RESTART stub.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: David Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-19-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
(cherry picked from commit 166cc2a4be0d80075d379b30d3e84895c878a1a8
 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/cpufeature)
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 175544340
Change-Id: Ib390651a635fe2f83dcc4d1a0c5a959eb892e5bd
This commit is contained in:
Marc Zyngier 2021-02-08 09:57:27 +00:00 committed by Will Deacon
parent 2163159d76
commit 1952c1aee8
1 changed files with 9 additions and 0 deletions
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9
Documentation/virt/kvm/arm/hyp-abi.rst
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@ -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 conditioned by the CPU supporting VHE, the EL2 MMU
being off, and VHE not being disabled by any other means (command line
option, for example).
Any other value of r0/x0 triggers a hypervisor-specific handling,
which is not documented here.