s390/entry: sort out physical vs virtual pointers usage in sie64a

Fix virtual vs physical address confusion (which currently are the
same).

sie_block is accessed in entry.S and passed it to hardware, which is why
both its physical and virtual address are needed. To avoid every caller
having to do the virtual-physical conversion, add a new function sie64a()
which converts the virtual address to physical.

Signed-off-by: Nico Boehr <[email protected]>
Reviewed-by: Alexander Gordeev <[email protected]>
Reviewed-by: Claudio Imbrenda <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Message-Id: <[email protected]>
Signed-off-by: Janosch Frank <[email protected]>

Author: Nico Boehr

arch/s390/include/asm/kvm_host.h

@@ -1017,7 +1017,13 @@ void kvm_arch_crypto_clear_masks(struct kvm *kvm);
 void kvm_arch_crypto_set_masks(struct kvm *kvm, unsigned long *apm,
 			       unsigned long *aqm, unsigned long *adm);
 
-extern int sie64a(struct kvm_s390_sie_block *, u64 *);
+int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa);
+
+static inline int sie64a(struct kvm_s390_sie_block *sie_block, u64 *rsa)
+{
+	return __sie64a(virt_to_phys(sie_block), sie_block, rsa);
+}
+
 extern char sie_exit;
 
 extern int kvm_s390_gisc_register(struct kvm *kvm, u32 gisc);

arch/s390/include/asm/stacktrace.h

@@ -46,6 +46,7 @@ struct stack_frame {
 			unsigned long sie_savearea;
 			unsigned long sie_reason;
 			unsigned long sie_flags;
+			unsigned long sie_control_block_phys;
 		};
 	};
 	unsigned long gprs[10];

arch/s390/kernel/asm-offsets.c

@@ -62,6 +62,7 @@ int main(void)
 	OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);
 	OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);
 	OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);
+	OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);
 	DEFINE(STACK_FRAME_OVERHEAD, sizeof(struct stack_frame));
 	BLANK();
 	/* idle data offsets */

arch/s390/kernel/entry.S

@@ -225,18 +225,20 @@ ENDPROC(__switch_to)
 
 #if IS_ENABLED(CONFIG_KVM)
 /*
- * sie64a calling convention:
- * %r2 pointer to sie control block
- * %r3 guest register save area
+ * __sie64a calling convention:
+ * %r2 pointer to sie control block phys
+ * %r3 pointer to sie control block virt
+ * %r4 guest register save area
  */
-ENTRY(sie64a)
+ENTRY(__sie64a)
 	stmg	%r6,%r14,__SF_GPRS(%r15)	# save kernel registers
 	lg	%r12,__LC_CURRENT
-	stg	%r2,__SF_SIE_CONTROL(%r15)	# save control block pointer
-	stg	%r3,__SF_SIE_SAVEAREA(%r15)	# save guest register save area
+	stg	%r2,__SF_SIE_CONTROL_PHYS(%r15)	# save sie block physical..
+	stg	%r3,__SF_SIE_CONTROL(%r15)	# ...and virtual addresses
+	stg	%r4,__SF_SIE_SAVEAREA(%r15)	# save guest register save area
 	xc	__SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
 	mvc	__SF_SIE_FLAGS(8,%r15),__TI_flags(%r12) # copy thread flags
-	lmg	%r0,%r13,0(%r3)			# load guest gprs 0-13
+	lmg	%r0,%r13,0(%r4)			# load guest gprs 0-13
 	lg	%r14,__LC_GMAP			# get gmap pointer
 	ltgr	%r14,%r14
 	jz	.Lsie_gmap
@@ -248,6 +250,7 @@ ENTRY(sie64a)
 	jnz	.Lsie_skip
 	TSTMSK	__LC_CPU_FLAGS,_CIF_FPU
 	jo	.Lsie_skip			# exit if fp/vx regs changed
+	lg	%r14,__SF_SIE_CONTROL_PHYS(%r15)	# get sie block phys addr
 	BPEXIT	__SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
 .Lsie_entry:
 	sie	0(%r14)
@@ -258,13 +261,14 @@ ENTRY(sie64a)
 	BPOFF
 	BPENTER	__SF_SIE_FLAGS(%r15),(_TIF_ISOLATE_BP|_TIF_ISOLATE_BP_GUEST)
 .Lsie_skip:
+	lg	%r14,__SF_SIE_CONTROL(%r15)	# get control block pointer
 	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE
 	lctlg	%c1,%c1,__LC_KERNEL_ASCE	# load primary asce
 .Lsie_done:
 # some program checks are suppressing. C code (e.g. do_protection_exception)
 # will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There
 # are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable.
-# Other instructions between sie64a and .Lsie_done should not cause program
+# Other instructions between __sie64a and .Lsie_done should not cause program
 # interrupts. So lets use 3 nops as a landing pad for all possible rewinds.
 .Lrewind_pad6:
 	nopr	7
@@ -293,8 +297,8 @@ sie_exit:
 	EX_TABLE(.Lrewind_pad4,.Lsie_fault)
 	EX_TABLE(.Lrewind_pad2,.Lsie_fault)
 	EX_TABLE(sie_exit,.Lsie_fault)
-ENDPROC(sie64a)
-EXPORT_SYMBOL(sie64a)
+ENDPROC(__sie64a)
+EXPORT_SYMBOL(__sie64a)
 EXPORT_SYMBOL(sie_exit)
 #endif
 
@@ -373,7 +377,7 @@ ENTRY(pgm_check_handler)
 	j	3f			# -> fault in user space
 .Lpgm_skip_asce:
 #if IS_ENABLED(CONFIG_KVM)
-	# cleanup critical section for program checks in sie64a
+	# cleanup critical section for program checks in __sie64a
 	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,1f
 	SIEEXIT
 	lghi	%r10,_PIF_GUEST_FAULT