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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: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Thomas Huth 2014-01-15 16:46:07 +01:00 committed by Christian Borntraeger
parent e029ae5b78
commit f14d82e06a
2 changed files with 49 additions and 5 deletions
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5
arch/s390/include/asm/kvm_host.h
View File

@ -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 */

49
arch/s390/kvm/intercept.c
View File

@ -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,