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Commit f14d82e0 authored by Thomas Huth's avatar Thomas Huth Committed by Christian Borntraeger
Browse files

KVM: s390: Fix external interrupt interception 



The external interrupt interception can only occur in rare cases, e.g.
when the PSW of the interrupt handler has a bad value. The old handler
for this interception simply ignored these events (except for increasing
the exit_external_interrupt counter), but for proper operation we either
have to inject the interrupts manually or we should drop to userspace in
case of errors.

Signed-off-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent e029ae5b

arch/s390/include/asm/kvm_host.h

+4 −1
Original line number Diff line number Diff line
@@ -132,7 +132,10 @@ struct kvm_s390_sie_block { 
	psw_t	gpsw;			/* 0x0090 */

	__u64	gg14;			/* 0x00a0 */

	__u64	gg15;			/* 0x00a8 */

	__u8	reservedb0[28];		/* 0x00b0 */

	__u8	reservedb0[20];		/* 0x00b0 */

	__u16	extcpuaddr;		/* 0x00c4 */

	__u16	eic;			/* 0x00c6 */

	__u32	reservedc8;		/* 0x00c8 */

	__u16	pgmilc;			/* 0x00cc */

	__u16	iprcc;			/* 0x00ce */

	__u32	dxc;			/* 0x00d0 */

arch/s390/kvm/intercept.c

+45 −4
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


#include <asm/kvm_host.h>

#include <asm/asm-offsets.h>

#include <asm/irq.h>



#include "kvm-s390.h"

#include "gaccess.h"
@@ -46,9 +47,6 @@ static int handle_noop(struct kvm_vcpu *vcpu) 
	case 0x10:

		vcpu->stat.exit_external_request++;

		break;

	case 0x14:

		vcpu->stat.exit_external_interrupt++;

		break;

	default:

		break; /* nothing */

	}
@@ -233,6 +231,49 @@ static int handle_instruction_and_prog(struct kvm_vcpu *vcpu) 
	return rc2;

}



/**

 * handle_external_interrupt - used for external interruption interceptions

 *

 * This interception only occurs if the CPUSTAT_EXT_INT bit was set, or if

 * the new PSW does not have external interrupts disabled. In the first case,

 * we've got to deliver the interrupt manually, and in the second case, we

 * drop to userspace to handle the situation there.

 */

static int handle_external_interrupt(struct kvm_vcpu *vcpu)

{

	u16 eic = vcpu->arch.sie_block->eic;

	struct kvm_s390_interrupt irq;

	psw_t newpsw;

	int rc;



	vcpu->stat.exit_external_interrupt++;



	rc = read_guest_lc(vcpu, __LC_EXT_NEW_PSW, &newpsw, sizeof(psw_t));

	if (rc)

		return rc;

	/* We can not handle clock comparator or timer interrupt with bad PSW */

	if ((eic == EXT_IRQ_CLK_COMP || eic == EXT_IRQ_CPU_TIMER) &&

	    (newpsw.mask & PSW_MASK_EXT))

		return -EOPNOTSUPP;



	switch (eic) {

	case EXT_IRQ_CLK_COMP:

		irq.type = KVM_S390_INT_CLOCK_COMP;

		break;

	case EXT_IRQ_CPU_TIMER:

		irq.type = KVM_S390_INT_CPU_TIMER;

		break;

	case EXT_IRQ_EXTERNAL_CALL:

		irq.type = KVM_S390_INT_EXTERNAL_CALL;

		irq.parm = vcpu->arch.sie_block->extcpuaddr;

		break;

	default:

		return -EOPNOTSUPP;

	}



	return kvm_s390_inject_vcpu(vcpu, &irq);

}



/**

 * Handle MOVE PAGE partial execution interception.

 *
@@ -291,7 +332,7 @@ static const intercept_handler_t intercept_funcs[] = { 
	[0x08 >> 2] = handle_prog,

	[0x0C >> 2] = handle_instruction_and_prog,

	[0x10 >> 2] = handle_noop,

	[0x14 >> 2] = handle_noop,

	[0x14 >> 2] = handle_external_interrupt,

	[0x18 >> 2] = handle_noop,

	[0x1C >> 2] = kvm_s390_handle_wait,

	[0x20 >> 2] = handle_validity,