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linux/arch/s390/kvm/intercept.c
Christian Borntraeger 2c70fe4416 s390/kvm: Kick guests out of sie if prefix page host pte is touched 
The guest prefix pages must be mapped writeable all the time
while SIE is running, otherwise the guest might see random
behaviour. (pinned at the pte level) Turns out that mlocking is
not enough, the page table entry (not the page) might change or
become r/o. This patch uses the gmap notifiers to kick guest
cpus out of SIE.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-05-21 11:55:24 +03:00

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/*
* in-kernel handling for sie intercepts
*
* Copyright IBM Corp. 2008, 2009
*
* 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"
#include "gaccess.h"
#include "trace.h"
#include "trace-s390.h"
static int handle_lctlg(struct kvm_vcpu *vcpu)
{
int reg1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
int reg3 = vcpu->arch.sie_block->ipa & 0x000f;
u64 useraddr;
int reg, rc;
vcpu->stat.instruction_lctlg++;
useraddr = kvm_s390_get_base_disp_rsy(vcpu);
if (useraddr & 7)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
reg = reg1;
VCPU_EVENT(vcpu, 5, "lctlg r1:%x, r3:%x, addr:%llx", reg1, reg3,
useraddr);
trace_kvm_s390_handle_lctl(vcpu, 1, reg1, reg3, useraddr);
do {
rc = get_guest(vcpu, vcpu->arch.sie_block->gcr[reg],
(u64 __user *) useraddr);
if (rc)
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
useraddr += 8;
if (reg == reg3)
break;
reg = (reg + 1) % 16;
} while (1);
return 0;
}
static int handle_lctl(struct kvm_vcpu *vcpu)
{
int reg1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
int reg3 = vcpu->arch.sie_block->ipa & 0x000f;
u64 useraddr;
u32 val = 0;
int reg, rc;
vcpu->stat.instruction_lctl++;
useraddr = kvm_s390_get_base_disp_rs(vcpu);
if (useraddr & 3)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
VCPU_EVENT(vcpu, 5, "lctl r1:%x, r3:%x, addr:%llx", reg1, reg3,
useraddr);
trace_kvm_s390_handle_lctl(vcpu, 0, reg1, reg3, useraddr);
reg = reg1;
do {
rc = get_guest(vcpu, val, (u32 __user *) useraddr);
if (rc)
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
vcpu->arch.sie_block->gcr[reg] &= 0xffffffff00000000ul;
vcpu->arch.sie_block->gcr[reg] |= val;
useraddr += 4;
if (reg == reg3)
break;
reg = (reg + 1) % 16;
} while (1);
return 0;
}
static const intercept_handler_t eb_handlers[256] = {
[0x2f] = handle_lctlg,
[0x8a] = kvm_s390_handle_priv_eb,
};
static int handle_eb(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
handler = eb_handlers[vcpu->arch.sie_block->ipb & 0xff];
if (handler)
return handler(vcpu);
return -EOPNOTSUPP;
}
static const intercept_handler_t instruction_handlers[256] = {
[0x01] = kvm_s390_handle_01,
[0x82] = kvm_s390_handle_lpsw,
[0x83] = kvm_s390_handle_diag,
[0xae] = kvm_s390_handle_sigp,
[0xb2] = kvm_s390_handle_b2,
[0xb7] = handle_lctl,
[0xb9] = kvm_s390_handle_b9,
[0xe5] = kvm_s390_handle_e5,
[0xeb] = handle_eb,
};
static int handle_noop(struct kvm_vcpu *vcpu)
{
switch (vcpu->arch.sie_block->icptcode) {
case 0x0:
vcpu->stat.exit_null++;
break;
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)
{
int rc = 0;
vcpu->stat.exit_stop_request++;
spin_lock_bh(&vcpu->arch.local_int.lock);
trace_kvm_s390_stop_request(vcpu->arch.local_int.action_bits);
if (vcpu->arch.local_int.action_bits & ACTION_RELOADVCPU_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_RELOADVCPU_ON_STOP;
rc = SIE_INTERCEPT_RERUNVCPU;
vcpu->run->exit_reason = KVM_EXIT_INTR;
}
if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
atomic_set_mask(CPUSTAT_STOPPED,
&vcpu->arch.sie_block->cpuflags);
vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
rc = -EOPNOTSUPP;
}
if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
/* store status must be called unlocked. Since local_int.lock
* only protects local_int.* and not guest memory we can give
* up the lock here */
spin_unlock_bh(&vcpu->arch.local_int.lock);
rc = kvm_s390_vcpu_store_status(vcpu,
KVM_S390_STORE_STATUS_NOADDR);
if (rc >= 0)
rc = -EOPNOTSUPP;
} else
spin_unlock_bh(&vcpu->arch.local_int.lock);
return rc;
}
static int handle_validity(struct kvm_vcpu *vcpu)
{
int viwhy = vcpu->arch.sie_block->ipb >> 16;
vcpu->stat.exit_validity++;
trace_kvm_s390_intercept_validity(vcpu, viwhy);
WARN_ONCE(true, "kvm: unhandled validity intercept 0x%x\n", viwhy);
return -EOPNOTSUPP;
}
static int handle_instruction(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
vcpu->stat.exit_instruction++;
trace_kvm_s390_intercept_instruction(vcpu,
vcpu->arch.sie_block->ipa,
vcpu->arch.sie_block->ipb);
handler = instruction_handlers[vcpu->arch.sie_block->ipa >> 8];
if (handler)
return handler(vcpu);
return -EOPNOTSUPP;
}
static int handle_prog(struct kvm_vcpu *vcpu)
{
vcpu->stat.exit_program_interruption++;
trace_kvm_s390_intercept_prog(vcpu, vcpu->arch.sie_block->iprcc);
return kvm_s390_inject_program_int(vcpu, vcpu->arch.sie_block->iprcc);
}
static int handle_instruction_and_prog(struct kvm_vcpu *vcpu)
{
int rc, rc2;
vcpu->stat.exit_instr_and_program++;
rc = handle_instruction(vcpu);
rc2 = handle_prog(vcpu);
if (rc == -EOPNOTSUPP)
vcpu->arch.sie_block->icptcode = 0x04;
if (rc)
return rc;
return rc2;
}
static const intercept_handler_t intercept_funcs[] = {
[0x00 >> 2] = handle_noop,
[0x04 >> 2] = handle_instruction,
[0x08 >> 2] = handle_prog,
[0x0C >> 2] = handle_instruction_and_prog,
[0x10 >> 2] = handle_noop,
[0x14 >> 2] = handle_noop,
[0x18 >> 2] = handle_noop,
[0x1C >> 2] = kvm_s390_handle_wait,
[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 >> 2) >= ARRAY_SIZE(intercept_funcs))
return -EOPNOTSUPP;
func = intercept_funcs[code >> 2];
if (func)
return func(vcpu);
return -EOPNOTSUPP;
}
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