On 12.05.2025 16:46, Ross Lagerwall wrote:
> --- a/xen/include/public/sysctl.h
> +++ b/xen/include/public/sysctl.h
> @@ -215,23 +215,51 @@ typedef struct pm_px_val pm_px_val_t;
> DEFINE_XEN_GUEST_HANDLE(pm_px_val_t);
>
> struct pm_px_stat {
> - uint8_t total; /* total Px states */
> - uint8_t usable; /* usable Px states */
> - uint8_t last; /* last Px state */
> - uint8_t cur; /* current Px state */
> - XEN_GUEST_HANDLE_64(uint64) trans_pt; /* Px transition table */
> + /*
> + * IN: Number of elements in pt, number of rows/columns in trans_pt
> + * (PMSTAT_get_pxstat)
> + * OUT: total Px states (PMSTAT_get_max_px, PMSTAT_get_pxstat)
> + */
> + uint8_t total;
The part for this field ought to go in patch 1, as already indicated there.
> + uint8_t usable; /* OUT: usable Px states (PMSTAT_get_pxstat) */
> + uint8_t last; /* OUT: last Px state (PMSTAT_get_pxstat) */
> + uint8_t cur; /* OUT: current Px state (PMSTAT_get_pxstat) */
> + /*
> + * OUT: Px transition table. This should have total * total elements.
> + * This will not be copied if it is smaller than the hypervisor's
> + * Px transition table. (PMSTAT_get_pxstat)
> + */
> + XEN_GUEST_HANDLE_64(uint64) trans_pt;
> + /* OUT: This should have total elements (PMSTAT_get_pxstat) */
> XEN_GUEST_HANDLE_64(pm_px_val_t) pt;
As also indicated there, the same constraint as for trans_pt applies to this
output buffer, just that it's having only one dimension.
> };
>
> struct pm_cx_stat {
> - uint32_t nr; /* entry nr in triggers & residencies, including C0 */
> - uint32_t last; /* last Cx state */
> - uint64_aligned_t idle_time; /* idle time from boot */
> - XEN_GUEST_HANDLE_64(uint64) triggers; /* Cx trigger counts */
> - XEN_GUEST_HANDLE_64(uint64) residencies; /* Cx residencies */
> - uint32_t nr_pc; /* entry nr in pc[] */
> - uint32_t nr_cc; /* entry nr in cc[] */
> /*
> + * IN: Number of elements in triggers, residencies (PMSTAT_get_cxstat)
> + * OUT: entry nr in triggers & residencies, including C0
> + * (PMSTAT_get_cxstat, PMSTAT_get_max_cx)
> + */
> + uint32_t nr;
> + uint32_t last; /* OUT: last Cx state (PMSTAT_get_cxstat) */
> + /* OUT: idle time from boot (PMSTAT_get_cxstat)*/
> + uint64_aligned_t idle_time;
> + /* OUT: Cx trigger counts, nr elements (PMSTAT_get_cxstat) */
> + XEN_GUEST_HANDLE_64(uint64) triggers;
> + /* OUT: Cx residencies, nr elements (PMSTAT_get_cxstat) */
> + XEN_GUEST_HANDLE_64(uint64) residencies;
> + /*
> + * IN: entry nr in pc[] (PMSTAT_get_cxstat)
> + * OUT: Index of highest non-zero entry set in pc[] (PMSTAT_get_cxstat)
> + */
> + uint32_t nr_pc;
> + /*
> + * IN: entry nr in cc[] (PMSTAT_get_cxstat)
> + * OUT: Index of highest non-zero entry set in cc[] (PMSTAT_get_cxstat)
> + */
For both of these, it's not "highest non-zero" but, according to ...
> + uint32_t nr_cc;
> + /*
> + * OUT: (PMSTAT_get_cxstat)
> * These two arrays may (and generally will) have unused slots; slots not
> * having a corresponding hardware register will not be written by the
> * hypervisor. It is therefore up to the caller to put a suitable
> sentinel
... this comment, "highest written by hypervisor". They're also not "index of",
but "one higher than the index of" (i.e. counts, not indexes).
Jan
