[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>

4 files changed, 6 insertions, 5 deletions

diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index 9e13c7d56cc..3b97964e0e9 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/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 */
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 751318765e2..0717363033e 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/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;
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 83a93747e2f..130fb02305c 100644
--- a/arch/s390/kernel/entry64.S
+++ b/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
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 66903eed36e..fc83f1f1513 100644
--- a/arch/s390/kernel/setup.c
+++ b/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;