s390/kvm: Mark if a cpu is in SIE

Lets track in a private bit if the sie control block is active.
We want to track this as closely as possible, so we also have to
instrument the interrupt and program check handler. Lets use the
existing HANDLE_SIE_INTERCEPT macro.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

3 files changed, 13 insertions, 4 deletions

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 16bd5d169cdb..962b92e6cf00 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -68,7 +68,10 @@ struct sca_block {
 struct kvm_s390_sie_block {
         atomic_t cpuflags;              /* 0x0000 */
         __u32   prefix;                 /* 0x0004 */
-        __u8    reserved8[32];          /* 0x0008 */
+        __u8    reserved08[4];          /* 0x0008 */
+#define PROG_IN_SIE (1<<0)
+        __u32   prog0c;                 /* 0x000c */
+        __u8    reserved10[24];         /* 0x0010 */
         __u64   cputm;                  /* 0x0028 */
         __u64   ckc;                    /* 0x0030 */
         __u64   epoch;                  /* 0x0038 */
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 7a82f9f70100..6456bbe1fbb1 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -7,6 +7,7 @@
 #define ASM_OFFSETS_C
 
 #include <linux/kbuild.h>
+#include <linux/kvm_host.h>
 #include <linux/sched.h>
 #include <asm/cputime.h>
 #include <asm/vdso.h>
@@ -161,6 +162,7 @@ int main(void)
         DEFINE(__LC_PGM_TDB, offsetof(struct _lowcore, pgm_tdb));
         DEFINE(__THREAD_trap_tdb, offsetof(struct task_struct, thread.trap_tdb));
         DEFINE(__GMAP_ASCE, offsetof(struct gmap, asce));
+        DEFINE(__SIE_PROG0C, offsetof(struct kvm_s390_sie_block, prog0c));
 #endif /* CONFIG_32BIT */
         return 0;
 }
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 4c17eece707e..c2e81b4ea42c 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -84,7 +84,7 @@ _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
         .macro  HANDLE_SIE_INTERCEPT scratch,pgmcheck
 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
         tmhh    %r8,0x0001              # interrupting from user ?
-        jnz     .+42
+        jnz     .+52
         lgr     \scratch,%r9
         slg     \scratch,BASED(.Lsie_loop)
         clg     \scratch,BASED(.Lsie_length)
@@ -92,12 +92,14 @@ _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
         # Some program interrupts are suppressing (e.g. protection).
         # We must also check the instruction after SIE in that case.
         # do_protection_exception will rewind to rewind_pad
-        jh      .+22
+        jh      .+32
         .else
-        jhe     .+22
+        jhe     .+32
         .endif
         lg      %r9,BASED(.Lsie_loop)
         LPP     BASED(.Lhost_id)        # set host id
+        lg      %r14,__SF_EMPTY(%r15)   # get control block pointer
+        ni      __SIE_PROG0C+3(%r14),0xfe       # no longer in SIE
 #endif
         .endm
 
@@ -956,10 +958,12 @@ sie_loop:
         lctlg   %c1,%c1,__GMAP_ASCE(%r14)       # load primary asce
 sie_gmap:
         lg      %r14,__SF_EMPTY(%r15)           # get control block pointer
+        oi      __SIE_PROG0C+3(%r14),1          # we are in SIE now
         LPP     __SF_EMPTY(%r15)                # set guest id
         sie     0(%r14)
 sie_done:
         LPP     __SF_EMPTY+16(%r15)             # set host id
+        ni      __SIE_PROG0C+3(%r14),0xfe       # no longer in SIE
         lg      %r14,__LC_THREAD_INFO           # pointer thread_info struct
 sie_exit:
         lctlg   %c1,%c1,__LC_USER_ASCE          # load primary asce