From: Janosch Frank <frankja@xxxxxxxxxxxxx> Let's explain in which situations the rc/rrc will set in struct kvm_pv_cmd so it's clear that the struct members should be set to 0. rc/rrc are independent of the IOCTL return code. Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx> Acked-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220517163629.3443-12-frankja@xxxxxxxxxxxxx Message-Id: <20220517163629.3443-12-frankja@xxxxxxxxxxxxx> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> --- Documentation/virt/kvm/api.rst | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 47d3064f5b79..0dd6d23c32ee 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -5127,6 +5127,14 @@ into ESA mode. This reset is a superset of the initial reset. __u32 reserved[3]; }; +**Ultravisor return codes** +The Ultravisor return (reason) codes are provided by the kernel if a +Ultravisor call has been executed to achieve the results expected by +the command. Therefore they are independent of the IOCTL return +code. If KVM changes `rc`, its value will always be greater than 0 +hence setting it to 0 before issuing a PV command is advised to be +able to detect a change of `rc`. + **cmd values:** KVM_PV_ENABLE -- 2.35.1
