[PATCH] KVM: arm64: Clarify vcpu reset behaviour
Marc Zyngier
maz at kernel.org
Thu Apr 8 11:36:34 BST 2021
On 2021-04-07 21:35, Will Deacon wrote:
> On Tue, Apr 06, 2021 at 01:58:41PM +0100, Marc Zyngier wrote:
>> 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.
>>
>> Signed-off-by: Marc Zyngier <maz at kernel.org>
>> ---
>> Documentation/virt/kvm/api.rst | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/Documentation/virt/kvm/api.rst
>> b/Documentation/virt/kvm/api.rst
>> index 38e327d4b479..e2237e4e10ba 100644
>> --- a/Documentation/virt/kvm/api.rst
>> +++ b/Documentation/virt/kvm/api.rst
>> @@ -3115,6 +3115,16 @@ optional features it should have. This will
>> cause a reset of the cpu
>> 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
>> + * Aarch32: SVC, D, A, I and F bits set
>
> nit, but capitalisation should be "AArch32"
>
> Is "SVC" sufficient, or do we also need to describe Arm vs Thumb?
SVC doesn't describe the instruction set, but we don't say that PSR.T
is set, which implies ARM.
I can add something like "All other bits are set to 0", if that makes it
clearer.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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