Re: [PATCH v4 2/9] powerpc/pseries/vas: Save PID in pseries_vas_window struct

[Nicholas Piggin <npiggin@gmail.com>]

Excerpts from Haren Myneni's message of February 20, 2022 5:55 am:
> 
> The kernel sets the VAS window with PID when it 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.

Thanks for renaming it lpid->pid and adding the comment.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

> 
> Signed-off-by: Haren Myneni <haren@linux.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/vas.c | 9 +++++----
>  arch/powerpc/platforms/pseries/vas.h | 1 +
>  2 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
> index 18aae037ffe9..1035446f985b 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->pid, 0,
>  					VAS_MOD_WIN_FLAGS, 0);
>  
>  		rc = hcall_return_busy_check(rc);
> @@ -124,8 +123,8 @@ static int h_modify_vas_window(struct pseries_vas_window *win)
>  	if (rc == H_SUCCESS)
>  		return 0;
>  
> -	pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u lpid %u\n",
> -			rc, win->vas_win.winid, lpid);
> +	pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u pid %u\n",
> +			rc, win->vas_win.winid, win->pid);
>  	return -EIO;
>  }
>  
> @@ -338,6 +337,8 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags,
>  		}
>  	}
>  
> +	txwin->pid = 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 d6ea8ab8b07a..2872532ed72a 100644
> --- a/arch/powerpc/platforms/pseries/vas.h
> +++ b/arch/powerpc/platforms/pseries/vas.h
> @@ -114,6 +114,7 @@ struct pseries_vas_window {
>  	u64 domain[6];		/* Associativity domain Ids */
>  				/* this window is allocated */
>  	u64 util;
> +	u32 pid;		/* PID associated with this window */
>  
>  	/* List of windows opened which is used for LPM */
>  	struct list_head win_list;
> -- 
> 2.27.0
> 
> 
>