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linux/arch/s390/kvm/intercept.c
Carsten Otte 3edbcff9bf KVM: s390: Sanity check on validity intercept 
This patch adds a sanity check for the content of the guest
prefix register content before faulting in the cpu lowcore
that it refers to. The guest might end up in an endless loop
where SIE complains about missing lowcore with incorrect
content of the prefix register without this fix.

Reported-by: Mijo Safradin <mijo@linux.vnet.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Ehrhardt <ehrhardt@de.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:56 +03:00

234 lines
5.4 KiB
C
Raw Blame History

/*
* 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"
#include "gaccess.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;
int base2 = vcpu->arch.sie_block->ipb >> 28;
int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16) +
((vcpu->arch.sie_block->ipb & 0xff00) << 4);
u64 useraddr;
int reg, rc;
vcpu->stat.instruction_lctlg++;
if ((vcpu->arch.sie_block->ipb & 0xff) != 0x2f)
return -ENOTSUPP;
useraddr = disp2;
if (base2)
useraddr += vcpu->arch.guest_gprs[base2];
if (useraddr & 7)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
reg = reg1;
VCPU_EVENT(vcpu, 5, "lctlg r1:%x, r3:%x,b2:%x,d2:%x", reg1, reg3, base2,
disp2);
do {
rc = get_guest_u64(vcpu, useraddr,
&vcpu->arch.sie_block->gcr[reg]);
if (rc == -EFAULT) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
break;
}
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;
int base2 = vcpu->arch.sie_block->ipb >> 28;
int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
u64 useraddr;
u32 val = 0;
int reg, rc;
vcpu->stat.instruction_lctl++;
useraddr = disp2;
if (base2)
useraddr += vcpu->arch.guest_gprs[base2];
if (useraddr & 3)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
VCPU_EVENT(vcpu, 5, "lctl r1:%x, r3:%x,b2:%x,d2:%x", reg1, reg3, base2,
disp2);
reg = reg1;
do {
rc = get_guest_u32(vcpu, useraddr, &val);
if (rc == -EFAULT) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
break;
}
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 intercept_handler_t instruction_handlers[256] = {
[0x83] = kvm_s390_handle_diag,
[0xae] = kvm_s390_handle_sigp,
[0xb2] = kvm_s390_handle_b2,
[0xb7] = handle_lctl,
[0xeb] = handle_lctlg,
};
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;
vcpu->stat.exit_stop_request++;
atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
spin_lock_bh(&vcpu->arch.local_int.lock);
if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP;
rc = __kvm_s390_vcpu_store_status(vcpu,
KVM_S390_STORE_STATUS_NOADDR);
if (rc >= 0)
rc = -ENOTSUPP;
}
if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) {
vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP;
VCPU_EVENT(vcpu, 3, "%s", "cpu stopped");
rc = -ENOTSUPP;
} else
rc = 0;
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;
int rc;
vcpu->stat.exit_validity++;
if ((viwhy == 0x37) && (vcpu->arch.sie_block->prefix
<= vcpu->kvm->arch.guest_memsize - 2*PAGE_SIZE)){
rc = fault_in_pages_writeable((char __user *)
vcpu->kvm->arch.guest_origin +
vcpu->arch.sie_block->prefix,
2*PAGE_SIZE);
if (rc)
/* user will receive sigsegv, exit to user */
rc = -ENOTSUPP;
} else
rc = -ENOTSUPP;
if (rc)
VCPU_EVENT(vcpu, 2, "unhandled validity intercept code %d",
viwhy);
return rc;
}
static int handle_instruction(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
vcpu->stat.exit_instruction++;
handler = instruction_handlers[vcpu->arch.sie_block->ipa >> 8];
if (handler)
return handler(vcpu);
return -ENOTSUPP;
}
static int handle_prog(struct kvm_vcpu *vcpu)
{
vcpu->stat.exit_program_interruption++;
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 == -ENOTSUPP)
vcpu->arch.sie_block->icptcode = 0x04;
if (rc)
return rc;
return rc2;
}
static const intercept_handler_t intercept_funcs[0x48 >> 2] = {
[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,
[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 > 0x48)
return -ENOTSUPP;
func = intercept_funcs[code >> 2];
if (func)
return func(vcpu);
return -ENOTSUPP;
}
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