powerpc/pseries/vas: Save PID in pseries_vas_window struct

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.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a57cbe6d292fe49ad55a0b49c5679d6a24d8fe73.camel@linux.ibm.com

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.

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;