Commit ab511973 authored by Christian Borntraeger's avatar Christian Borntraeger
Browse files

KVM: s390: vsie: Avoid injecting machine check on signal 



The recent XFER_TO_GUEST_WORK change resulted in a situation, where the
vsie code would interpret a signal during work as a machine check during
SIE as both use the EINTR return code.
The exit_reason of the sie64a function has nothing to do with the
kvm_run exit_reason. Rename it and define a specific code for machine
checks instead of abusing -EINTR.
rename exit_reason into sie_return to avoid the naming conflict
and change the code flow in vsie.c to have a separate variable for rc
and sie_return.

Fixes: 2bd1337a ("KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions")
Signed-off-by: default avatarChristian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
parent 1ca90f4a

arch/s390/include/asm/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -710,6 +710,9 @@ 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);



#define SIE64_RETURN_NORMAL	0

#define SIE64_RETURN_MCCK	1



int __sie64a(phys_addr_t sie_block_phys, struct kvm_s390_sie_block *sie_block, u64 *rsa,

	     unsigned long gasce);

arch/s390/include/asm/stacktrace.h

+1 −1
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ struct stack_frame { 
		struct {

			unsigned long sie_control_block;

			unsigned long sie_savearea;

			unsigned long sie_reason;

			unsigned long sie_return;

			unsigned long sie_flags;

			unsigned long sie_control_block_phys;

			unsigned long sie_guest_asce;

arch/s390/kernel/asm-offsets.c

+1 −1
Original line number Diff line number Diff line
@@ -63,7 +63,7 @@ int main(void) 
	OFFSET(__SF_EMPTY, stack_frame, empty[0]);

	OFFSET(__SF_SIE_CONTROL, stack_frame, sie_control_block);

	OFFSET(__SF_SIE_SAVEAREA, stack_frame, sie_savearea);

	OFFSET(__SF_SIE_REASON, stack_frame, sie_reason);

	OFFSET(__SF_SIE_RETURN, stack_frame, sie_return);

	OFFSET(__SF_SIE_FLAGS, stack_frame, sie_flags);

	OFFSET(__SF_SIE_CONTROL_PHYS, stack_frame, sie_control_block_phys);

	OFFSET(__SF_SIE_GUEST_ASCE, stack_frame, sie_guest_asce);

arch/s390/kernel/entry.S

+2 −2
Original line number Diff line number Diff line
@@ -200,7 +200,7 @@ SYM_FUNC_START(__sie64a) 
	stg	%r3,__SF_SIE_CONTROL(%r15)	# ...and virtual addresses

	stg	%r4,__SF_SIE_SAVEAREA(%r15)	# save guest register save area

	stg	%r5,__SF_SIE_GUEST_ASCE(%r15)	# save guest asce

	xc	__SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0

	xc	__SF_SIE_RETURN(8,%r15),__SF_SIE_RETURN(%r15) # return code = 0

	mvc	__SF_SIE_FLAGS(8,%r15),__TI_flags(%r14) # copy thread flags

	lmg	%r0,%r13,0(%r4)			# load guest gprs 0-13

	mvi	__TI_sie(%r14),1
@@ -237,7 +237,7 @@ SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL) 
	xgr	%r4,%r4

	xgr	%r5,%r5

	lmg	%r6,%r14,__SF_GPRS(%r15)	# restore kernel registers

	lg	%r2,__SF_SIE_REASON(%r15)	# return exit reason code

	lg	%r2,__SF_SIE_RETURN(%r15)	# return sie return code

	BR_EX	%r14

SYM_FUNC_END(__sie64a)

EXPORT_SYMBOL(__sie64a)

arch/s390/kernel/nmi.c

+2 −2
Original line number Diff line number Diff line
@@ -487,8 +487,8 @@ void notrace s390_do_machine_check(struct pt_regs *regs) 
	mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);

	if (test_cpu_flag(CIF_MCCK_GUEST) &&

	(mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {

		/* Set exit reason code for host's later handling */

		*((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;

		/* Set sie return code for host's later handling */

		((struct stack_frame *)regs->gprs[15])->sie_return = SIE64_RETURN_MCCK;

	}

	clear_cpu_flag(CIF_MCCK_GUEST);