Excerpts from Haren Myneni's message of January 22, 2022 5:55 am:
>
> The kernel sets the VAS window with partition PID when is opened in
> the hypervisor. During DLPAR operation, windows can be closed and
> reopened in the hypervisor when the credit is available. So saves
> this PID in pseries_vas_window struct when the window is opened
> initially and reuse it later during DLPAR operation.
This probably shouldn't be called lpid, while you're changing it.
"partition PID" and "LPAR PID" is also confusing. I know the name
somewhat comes from the specifiction, but pid/PID would be fine,
it's clear we are talking about "this LPAR" when in pseries code.
>
> Signed-off-by: Haren Myneni <ha...@linux.ibm.com>
> ---
> arch/powerpc/platforms/pseries/vas.c | 7 ++++---
> arch/powerpc/platforms/pseries/vas.h | 1 +
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/vas.c
> b/arch/powerpc/platforms/pseries/vas.c
> index d2c8292bfb33..2ef56157634f 100644
> --- a/arch/powerpc/platforms/pseries/vas.c
> +++ b/arch/powerpc/platforms/pseries/vas.c
> @@ -107,7 +107,6 @@ static int h_deallocate_vas_window(u64 winid)
> static int h_modify_vas_window(struct pseries_vas_window *win)
> {
> long rc;
> - u32 lpid = mfspr(SPRN_PID);
>
> /*
> * AMR value is not supported in Linux VAS implementation.
> @@ -115,7 +114,7 @@ static int h_modify_vas_window(struct
> pseries_vas_window *win)
> */
> do {
> rc = plpar_hcall_norets(H_MODIFY_VAS_WINDOW,
> - win->vas_win.winid, lpid, 0,
> + win->vas_win.winid, win->lpid,
> 0,
> VAS_MOD_WIN_FLAGS, 0);
>
> rc = hcall_return_busy_check(rc);
> @@ -125,7 +124,7 @@ static int h_modify_vas_window(struct
> pseries_vas_window *win)
> return 0;
>
> pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u lpid %u\n",
> - rc, win->vas_win.winid, lpid);
> + rc, win->vas_win.winid, win->lpid);
> return -EIO;
> }
>
> @@ -338,6 +337,8 @@ static struct vas_window *vas_allocate_window(int
> vas_id, u64 flags,
> }
> }
>
> + txwin->lpid = mfspr(SPRN_PID);
> +
> /*
> * Allocate / Deallocate window hcalls and setup / free IRQs
> * have to be protected with mutex.
> diff --git a/arch/powerpc/platforms/pseries/vas.h
> b/arch/powerpc/platforms/pseries/vas.h
> index fa7ce74f1e49..0538760d13be 100644
> --- a/arch/powerpc/platforms/pseries/vas.h
> +++ b/arch/powerpc/platforms/pseries/vas.h
> @@ -115,6 +115,7 @@ struct pseries_vas_window {
> u64 domain[6]; /* Associativity domain Ids */
> /* this window is allocated */
> u64 util;
> + u32 lpid;
Comment could be "PID associated with this window".
BTW, is the TID parameter deprecated? Doesn't seem that we use that.
Thanks,
Nick
