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KVM: s390: sie intercept handling

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This path introduces handling of sie intercepts in three flavors: Intercepts
are either handled completely in-kernel by kvm_handle_sie_intercept(),
or passed to userspace with corresponding data in struct kvm_run in case
kvm_handle_sie_intercept() returns -ENOTSUPP.
In case of partial execution in kernel with the need of userspace support,
kvm_handle_sie_intercept() may choose to set up struct kvm_run and return
-EREMOTE.

The trivial intercept reasons are handled in this patch:
handle_noop() just does nothing for intercepts that don't require our support
  at all
handle_stop() is called when a cpu enters stopped state, and it drops out to
  userland after updating our vcpu state
handle_validity() faults in the cpu lowcore if needed, or passes the request
  to userland

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Christian Borntraeger
2008-03-25 18:47:23 +01:00
committed by Avi Kivity
parent b0c632db63
commit 8f2abe6a1e
6 changed files with 146 additions and 2 deletions
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46
arch/s390/kvm/kvm-s390.c
View File

@@ -23,12 +23,17 @@
#include <asm/lowcore.h>
#include <asm/pgtable.h>
#include "kvm-s390.h"
#include "gaccess.h"
#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "userspace_handled", VCPU_STAT(exit_userspace) },
{ "exit_validity", VCPU_STAT(exit_validity) },
{ "exit_stop_request", VCPU_STAT(exit_stop_request) },
{ "exit_external_request", VCPU_STAT(exit_external_request) },
{ "exit_external_interrupt", VCPU_STAT(exit_external_interrupt) },
{ NULL }
};
@@ -380,6 +385,7 @@ static void __vcpu_run(struct kvm_vcpu *vcpu)
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
int rc;
sigset_t sigsaved;
vcpu_load(vcpu);
@@ -389,7 +395,45 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
__vcpu_run(vcpu);
switch (kvm_run->exit_reason) {
case KVM_EXIT_S390_SIEIC:
vcpu->arch.sie_block->gpsw.mask = kvm_run->s390_sieic.mask;
vcpu->arch.sie_block->gpsw.addr = kvm_run->s390_sieic.addr;
break;
case KVM_EXIT_UNKNOWN:
case KVM_EXIT_S390_RESET:
break;
default:
BUG();
}
might_sleep();
do {
__vcpu_run(vcpu);
rc = kvm_handle_sie_intercept(vcpu);
} while (!signal_pending(current) && !rc);
if (signal_pending(current) && !rc)
rc = -EINTR;
if (rc == -ENOTSUPP) {
/* intercept cannot be handled in-kernel, prepare kvm-run */
kvm_run->exit_reason = KVM_EXIT_S390_SIEIC;
kvm_run->s390_sieic.icptcode = vcpu->arch.sie_block->icptcode;
kvm_run->s390_sieic.mask = vcpu->arch.sie_block->gpsw.mask;
kvm_run->s390_sieic.addr = vcpu->arch.sie_block->gpsw.addr;
kvm_run->s390_sieic.ipa = vcpu->arch.sie_block->ipa;
kvm_run->s390_sieic.ipb = vcpu->arch.sie_block->ipb;
rc = 0;
}
if (rc == -EREMOTE) {
/* intercept was handled, but userspace support is needed
* kvm_run has been prepared by the handler */
rc = 0;
}
if (vcpu->sigset_active)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);