From: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 5 +++-
arch/s390/kvm/intercept.c | 49 ++++++++++++++++++++++++++++++++++++----
2 files changed, 49 insertions(+), 5 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index f0a1dc5..96b8a67 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -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 */
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 99e4b76..bd607cf 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -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 */
}
@@ -234,6 +232,49 @@ static int handle_instruction_and_prog(struct kvm_vcpu *vcpu)
}
/**
+ * 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.
*
* This interception can only happen for guests with DAT disabled and
@@ -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,
--
1.8.4.2
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