Messages in this thread |  | | Subject | Re: [PATCH v6 04/18] KVM: arm64: Support SDEI_EVENT_REGISTER hypercall | From | Gavin Shan <> | Date | Mon, 2 May 2022 15:28:24 +0800 |
| |
Hi Oliver,
On 5/2/22 11:43 AM, Oliver Upton wrote: > On Mon, May 02, 2022 at 10:55:51AM +0800, Gavin Shan wrote: >>>> + unsigned long route_mode = smccc_get_arg(vcpu, 4); >>> >>> This is really 'flags'. route_mode is bit[0]. I imagine we don't want to >>> support relative mode, so bit[1] is useless for us in that case too. >>> >>> The spec is somewhat imprecise on what happens for reserved flags. The >>> prototype in section 5.1.2 of [1] suggests that reserved bits must be >>> zero, but 5.1.2.3 'Client responsibilities' does not state that invalid >>> flags result in an error. >>> >>> Arm TF certainly rejects unexpected flags [2]. >>> >>> [1]: DEN0054C https://developer.arm.com/documentation/den0054/latest >>> [2]: https://github.com/ARM-software/arm-trusted-firmware/blob/66c3906e4c32d675eb06bd081de8a3359f76b84c/services/std_svc/sdei/sdei_main.c#L260 >>> >> >> Yes, This chunk of code is still stick to old specification. Lets >> improve in next respin: >> >> - Rename @route_mode to @flags >> - Reject if the reserved bits are set. >> - Reject if relative mode (bit#1) is selected. >> - Reject if routing mode (bit#0) isn't RM_ANY (0). > > Bit[0] is ignored for private events, actually. So we really just reject > if any of bit[63:1] are set. >
It makes sense to me. Thanks for your confirm :)
Thanks, Gavin
|  |