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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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80
arch/s390/kvm/intercept.c Normal file
View File

@@ -0,0 +1,80 @@
/*
* intercept.c - in-kernel handling for sie intercepts
*
* Copyright IBM Corp. 2008
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Christian Borntraeger <borntraeger@de.ibm.com>
*/
#include <linux/kvm_host.h>
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <asm/kvm_host.h>
#include "kvm-s390.h"
static int handle_noop(struct kvm_vcpu *vcpu)
{
switch (vcpu->arch.sie_block->icptcode) {
case 0x10:
vcpu->stat.exit_external_request++;
break;
case 0x14:
vcpu->stat.exit_external_interrupt++;
break;
default:
break; /* nothing */
}
return 0;
}
static int handle_stop(struct kvm_vcpu *vcpu)
{
vcpu->stat.exit_stop_request++;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
return -ENOTSUPP;
}
static int handle_validity(struct kvm_vcpu *vcpu)
{
int viwhy = vcpu->arch.sie_block->ipb >> 16;
vcpu->stat.exit_validity++;
if (viwhy == 0x37) {
fault_in_pages_writeable((char __user *)
vcpu->kvm->arch.guest_origin +
vcpu->arch.sie_block->prefix,
PAGE_SIZE);
return 0;
}
VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",
viwhy);
return -ENOTSUPP;
}
static const intercept_handler_t intercept_funcs[0x48 >> 2] = {
[0x00 >> 2] = handle_noop,
[0x10 >> 2] = handle_noop,
[0x14 >> 2] = handle_noop,
[0x20 >> 2] = handle_validity,
[0x28 >> 2] = handle_stop,
};
int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
{
intercept_handler_t func;
u8 code = vcpu->arch.sie_block->icptcode;
if (code & 3 || code > 0x48)
return -ENOTSUPP;
func = intercept_funcs[code >> 2];
if (func)
return func(vcpu);
return -ENOTSUPP;
}