On Fri, Nov 14, 2025 at 07:22:41AM -0800, Sean Christopherson wrote: > On Fri, Nov 14, 2025, Michael Kelley wrote: > > From: Sean Christopherson <[email protected]> Sent: Thursday, November 13, > > 2025 2:56 PM > > > > > > > Adding Microsoft's Nuno Das Neves to the "To:" line since he > > originated the work to keep the Linux headers such as hvgdk.h in > > sync with the Windows counterparts from which they originate. > > ... > > > > /* Exit code reserved for hypervisor/software use */ > > > -#define SVM_EXIT_SW 0xf0000000 > > > +#define SVM_EXIT_SW 0xf0000000ull > > > > > > -#define SVM_EXIT_ERR -1 > > > +#define SVM_EXIT_ERR -1ull > > > > > > > [snip] > > > > > diff --git a/include/hyperv/hvgdk.h b/include/hyperv/hvgdk.h > > > index dd6d4939ea29..56b695873a72 100644 > > > --- a/include/hyperv/hvgdk.h > > > +++ b/include/hyperv/hvgdk.h > > > @@ -281,7 +281,7 @@ struct hv_vmcb_enlightenments { > > > #define HV_VMCB_NESTED_ENLIGHTENMENTS 31 > > > > > > /* Synthetic VM-Exit */ > > > -#define HV_SVM_EXITCODE_ENL 0xf0000000 > > > +#define HV_SVM_EXITCODE_ENL 0xf0000000u > > > > Is there a reason for making this Hyper-V code just "u", while > > making the SVM_VMGEXIT_* values "ull"? I don't think > > "u" vs. "ull" shouldn't make any difference when assigning to a > > u64, but the inconsistency piqued my interest .... > > I hedged and went for a more "minimal" change because it isn't KVM code, and > at > the time because I thought the value isn't defined by the APM. Though looking > again at the APM, it does reserve that value for software > > F000_000h Unused Reserved for Host. > > and I can't find anything in the TLFS. Ah, my PDF copy is just stale, it's > indeed > defined as a synthetic exit. > > > https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/nested-virtualization#synthetic-vm-exit > > Anyways, I'm in favor of making HV_SVM_EXITCODE_ENL an ull, though part of me > wonders if we should do: > > #define HV_SVM_EXITCODE_ENL SVM_EXIT_SW
I know this is very tempting, but these headers are supposed to mirror Microsoft's internal headers, so we would like to keep them self-contained for ease of tracking. It should be fine to add the "ull" suffix here. I briefly talked to a hypervisor developer and they agreed. Thanks, Wei
