[S390] kvm: move cmf host id constant out of lowcore

There is no reason for the cpu-measurement-facility host id constant to
reside in the lowcore where space is precious. Use an entry in the literal
pool in HANDLE_SIE_INTERCEPT and a stack slot in sie64a.
While we are at it replace the id -1 with 0 to indicate host execution.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/lowcore.h

@@ -271,7 +271,7 @@ struct _lowcore {
 	__u64	machine_flags;			/* 0x0360 */
 	__u64	ftrace_func;			/* 0x0368 */
 	__u64	gmap;				/* 0x0370 */
-	__u64	cmf_hpp;			/* 0x0378 */
+	__u8	pad_0x0378[0x0380-0x0378];	/* 0x0378 */
 
 	/* Interrupt response block. */
 	__u8	irb[64];			/* 0x0380 */

arch/s390/kernel/asm-offsets.c

@@ -150,7 +150,6 @@ int main(void)
 	DEFINE(__LC_LAST_BREAK, offsetof(struct _lowcore, breaking_event_addr));
 	DEFINE(__LC_VDSO_PER_CPU, offsetof(struct _lowcore, vdso_per_cpu_data));
 	DEFINE(__LC_GMAP, offsetof(struct _lowcore, gmap));
-	DEFINE(__LC_CMF_HPP, offsetof(struct _lowcore, cmf_hpp));
 	DEFINE(__GMAP_ASCE, offsetof(struct gmap, asce));
 #endif /* CONFIG_32BIT */
 	return 0;

arch/s390/kernel/entry64.S

@@ -71,7 +71,7 @@ _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
 	tm	__TI_flags+6(%r12),_TIF_SIE>>8
 	jz	0f
-	SPP	__LC_CMF_HPP			# set host id
+	SPP	BASED(.Lhost_id)		# set host id
 	clc	SP_PSW+8(8,%r15),BASED(.Lsie_loop)
 	jl	0f
 	clc	SP_PSW+8(8,%r15),BASED(.Lsie_done)
@@ -1054,6 +1054,7 @@ ENTRY(sie64a)
 	stmg	%r6,%r14,__SF_GPRS(%r15)	# save kernel registers
 	stg	%r2,__SF_EMPTY(%r15)		# save control block pointer
 	stg	%r3,__SF_EMPTY+8(%r15)		# save guest register save area
+	xc	__SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # host id == 0
 	lmg	%r0,%r13,0(%r3)			# load guest gprs 0-13
 	lg	%r14,__LC_THREAD_INFO		# pointer thread_info struct
 	oi	__TI_flags+6(%r14),_TIF_SIE>>8
@@ -1070,7 +1071,7 @@ sie_gmap:
 	SPP	__SF_EMPTY(%r15)		# set guest id
 	sie	0(%r14)
 sie_done:
-	SPP	__LC_CMF_HPP			# set host id
+	SPP	__SF_EMPTY+16(%r15)		# set host id
 	lg	%r14,__LC_THREAD_INFO		# pointer thread_info struct
 sie_exit:
 	lctlg	%c1,%c1,__LC_USER_ASCE		# load primary asce
@@ -1095,6 +1096,8 @@ sie_fault:
 	.quad	sie_loop
 .Lsie_done:
 	.quad	sie_done
+.Lhost_id:
+	.quad	0
 
 	.section __ex_table,"a"
 	.quad	sie_loop,sie_fault

arch/s390/kernel/setup.c

@@ -400,7 +400,6 @@ setup_lowcore(void)
 		__ctl_set_bit(14, 29);
 	}
 #else
-	lc->cmf_hpp = -1ULL;
 	lc->vdso_per_cpu_data = (unsigned long) &lc->paste[0];
 #endif
 	lc->sync_enter_timer = S390_lowcore.sync_enter_timer;