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linux/arch/s390/kvm/priv.c
Heiko Carstens dc5008b9bf s390/kvm: remove explicit -EFAULT return code checking on guest access 
Let's change to the paradigm that every return code from guest memory
access functions that is not zero translates to -EFAULT and do not
explictly compare.
Explictly comparing the return value with -EFAULT has already shown to
be a bit fragile. In addition this is closer to the handling of
copy_to/from_user functions, which imho is in general a good idea.

Also shorten the return code handling in interrupt.c a bit.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-03-07 16:21:21 -03:00

638 lines
16 KiB
C
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/*
* handling privileged instructions
*
* 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.h>
#include <linux/gfp.h>
#include <linux/errno.h>
#include <asm/current.h>
#include <asm/debug.h>
#include <asm/ebcdic.h>
#include <asm/sysinfo.h>
#include <asm/ptrace.h>
#include <asm/compat.h>
#include "gaccess.h"
#include "kvm-s390.h"
#include "trace.h"
static int handle_set_prefix(struct kvm_vcpu *vcpu)
{
u64 operand2;
u32 address = 0;
u8 tmp;
vcpu->stat.instruction_spx++;
operand2 = kvm_s390_get_base_disp_s(vcpu);
/* must be word boundary */
if (operand2 & 3) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
/* get the value */
if (get_guest_u32(vcpu, operand2, &address)) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
address = address & 0x7fffe000u;
/* make sure that the new value is valid memory */
if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
(copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1))) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
kvm_s390_set_prefix(vcpu, address);
VCPU_EVENT(vcpu, 5, "setting prefix to %x", address);
trace_kvm_s390_handle_prefix(vcpu, 1, address);
out:
return 0;
}
static int handle_store_prefix(struct kvm_vcpu *vcpu)
{
u64 operand2;
u32 address;
vcpu->stat.instruction_stpx++;
operand2 = kvm_s390_get_base_disp_s(vcpu);
/* must be word boundary */
if (operand2 & 3) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
address = vcpu->arch.sie_block->prefix;
address = address & 0x7fffe000u;
/* get the value */
if (put_guest_u32(vcpu, operand2, address)) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
VCPU_EVENT(vcpu, 5, "storing prefix to %x", address);
trace_kvm_s390_handle_prefix(vcpu, 0, address);
out:
return 0;
}
static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
{
u64 useraddr;
int rc;
vcpu->stat.instruction_stap++;
useraddr = kvm_s390_get_base_disp_s(vcpu);
if (useraddr & 1) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
if (rc) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
VCPU_EVENT(vcpu, 5, "storing cpu address to %llx", useraddr);
trace_kvm_s390_handle_stap(vcpu, useraddr);
out:
return 0;
}
static int handle_skey(struct kvm_vcpu *vcpu)
{
vcpu->stat.instruction_storage_key++;
vcpu->arch.sie_block->gpsw.addr -= 4;
VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation");
return 0;
}
static int handle_tpi(struct kvm_vcpu *vcpu)
{
u64 addr;
struct kvm_s390_interrupt_info *inti;
int cc;
addr = kvm_s390_get_base_disp_s(vcpu);
inti = kvm_s390_get_io_int(vcpu->kvm, vcpu->run->s.regs.crs[6], 0);
if (inti) {
if (addr) {
/*
* Store the two-word I/O interruption code into the
* provided area.
*/
put_guest_u16(vcpu, addr, inti->io.subchannel_id);
put_guest_u16(vcpu, addr + 2, inti->io.subchannel_nr);
put_guest_u32(vcpu, addr + 4, inti->io.io_int_parm);
} else {
/*
* Store the three-word I/O interruption code into
* the appropriate lowcore area.
*/
put_guest_u16(vcpu, 184, inti->io.subchannel_id);
put_guest_u16(vcpu, 186, inti->io.subchannel_nr);
put_guest_u32(vcpu, 188, inti->io.io_int_parm);
put_guest_u32(vcpu, 192, inti->io.io_int_word);
}
cc = 1;
} else
cc = 0;
kfree(inti);
/* Set condition code and we're done. */
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
vcpu->arch.sie_block->gpsw.mask |= (cc & 3ul) << 44;
return 0;
}
static int handle_tsch(struct kvm_vcpu *vcpu)
{
struct kvm_s390_interrupt_info *inti;
inti = kvm_s390_get_io_int(vcpu->kvm, 0,
vcpu->run->s.regs.gprs[1]);
/*
* Prepare exit to userspace.
* We indicate whether we dequeued a pending I/O interrupt
* so that userspace can re-inject it if the instruction gets
* a program check. While this may re-order the pending I/O
* interrupts, this is no problem since the priority is kept
* intact.
*/
vcpu->run->exit_reason = KVM_EXIT_S390_TSCH;
vcpu->run->s390_tsch.dequeued = !!inti;
if (inti) {
vcpu->run->s390_tsch.subchannel_id = inti->io.subchannel_id;
vcpu->run->s390_tsch.subchannel_nr = inti->io.subchannel_nr;
vcpu->run->s390_tsch.io_int_parm = inti->io.io_int_parm;
vcpu->run->s390_tsch.io_int_word = inti->io.io_int_word;
}
vcpu->run->s390_tsch.ipb = vcpu->arch.sie_block->ipb;
kfree(inti);
return -EREMOTE;
}
static int handle_io_inst(struct kvm_vcpu *vcpu)
{
VCPU_EVENT(vcpu, 4, "%s", "I/O instruction");
if (vcpu->kvm->arch.css_support) {
/*
* Most I/O instructions will be handled by userspace.
* Exceptions are tpi and the interrupt portion of tsch.
*/
if (vcpu->arch.sie_block->ipa == 0xb236)
return handle_tpi(vcpu);
if (vcpu->arch.sie_block->ipa == 0xb235)
return handle_tsch(vcpu);
/* Handle in userspace. */
return -EOPNOTSUPP;
} else {
/*
* Set condition code 3 to stop the guest from issueing channel
* I/O instructions.
*/
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
return 0;
}
}
static int handle_stfl(struct kvm_vcpu *vcpu)
{
unsigned int facility_list;
int rc;
vcpu->stat.instruction_stfl++;
/* only pass the facility bits, which we can handle */
facility_list = S390_lowcore.stfl_fac_list & 0xff00fff3;
rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
&facility_list, sizeof(facility_list));
if (rc)
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
else {
VCPU_EVENT(vcpu, 5, "store facility list value %x",
facility_list);
trace_kvm_s390_handle_stfl(vcpu, facility_list);
}
return 0;
}
static void handle_new_psw(struct kvm_vcpu *vcpu)
{
/* Check whether the new psw is enabled for machine checks. */
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_MCHECK)
kvm_s390_deliver_pending_machine_checks(vcpu);
}
#define PSW_MASK_ADDR_MODE (PSW_MASK_EA | PSW_MASK_BA)
#define PSW_MASK_UNASSIGNED 0xb80800fe7fffffffUL
#define PSW_ADDR_24 0x00000000000fffffUL
#define PSW_ADDR_31 0x000000007fffffffUL
int kvm_s390_handle_lpsw(struct kvm_vcpu *vcpu)
{
u64 addr;
psw_compat_t new_psw;
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
addr = kvm_s390_get_base_disp_s(vcpu);
if (addr & 7) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
if (copy_from_guest(vcpu, &new_psw, addr, sizeof(new_psw))) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
if (!(new_psw.mask & PSW32_MASK_BASE)) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
vcpu->arch.sie_block->gpsw.mask =
(new_psw.mask & ~PSW32_MASK_BASE) << 32;
vcpu->arch.sie_block->gpsw.addr = new_psw.addr;
if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_UNASSIGNED) ||
(!(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_ADDR_MODE) &&
(vcpu->arch.sie_block->gpsw.addr & ~PSW_ADDR_24)) ||
((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_ADDR_MODE) ==
PSW_MASK_EA)) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
handle_new_psw(vcpu);
out:
return 0;
}
static int handle_lpswe(struct kvm_vcpu *vcpu)
{
u64 addr;
psw_t new_psw;
addr = kvm_s390_get_base_disp_s(vcpu);
if (addr & 7) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
if (copy_from_guest(vcpu, &new_psw, addr, sizeof(new_psw))) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
vcpu->arch.sie_block->gpsw.mask = new_psw.mask;
vcpu->arch.sie_block->gpsw.addr = new_psw.addr;
if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_UNASSIGNED) ||
(((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_ADDR_MODE) ==
PSW_MASK_BA) &&
(vcpu->arch.sie_block->gpsw.addr & ~PSW_ADDR_31)) ||
(!(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_ADDR_MODE) &&
(vcpu->arch.sie_block->gpsw.addr & ~PSW_ADDR_24)) ||
((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_ADDR_MODE) ==
PSW_MASK_EA)) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
handle_new_psw(vcpu);
out:
return 0;
}
static int handle_stidp(struct kvm_vcpu *vcpu)
{
u64 operand2;
int rc;
vcpu->stat.instruction_stidp++;
operand2 = kvm_s390_get_base_disp_s(vcpu);
if (operand2 & 7) {
kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
goto out;
}
rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
if (rc) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out;
}
VCPU_EVENT(vcpu, 5, "%s", "store cpu id");
out:
return 0;
}
static void handle_stsi_3_2_2(struct kvm_vcpu *vcpu, struct sysinfo_3_2_2 *mem)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
int cpus = 0;
int n;
spin_lock(&fi->lock);
for (n = 0; n < KVM_MAX_VCPUS; n++)
if (fi->local_int[n])
cpus++;
spin_unlock(&fi->lock);
/* deal with other level 3 hypervisors */
if (stsi(mem, 3, 2, 2))
mem->count = 0;
if (mem->count < 8)
mem->count++;
for (n = mem->count - 1; n > 0 ; n--)
memcpy(&mem->vm[n], &mem->vm[n - 1], sizeof(mem->vm[0]));
mem->vm[0].cpus_total = cpus;
mem->vm[0].cpus_configured = cpus;
mem->vm[0].cpus_standby = 0;
mem->vm[0].cpus_reserved = 0;
mem->vm[0].caf = 1000;
memcpy(mem->vm[0].name, "KVMguest", 8);
ASCEBC(mem->vm[0].name, 8);
memcpy(mem->vm[0].cpi, "KVM/Linux ", 16);
ASCEBC(mem->vm[0].cpi, 16);
}
static int handle_stsi(struct kvm_vcpu *vcpu)
{
int fc = (vcpu->run->s.regs.gprs[0] & 0xf0000000) >> 28;
int sel1 = vcpu->run->s.regs.gprs[0] & 0xff;
int sel2 = vcpu->run->s.regs.gprs[1] & 0xffff;
u64 operand2;
unsigned long mem;
vcpu->stat.instruction_stsi++;
VCPU_EVENT(vcpu, 4, "stsi: fc: %x sel1: %x sel2: %x", fc, sel1, sel2);
operand2 = kvm_s390_get_base_disp_s(vcpu);
if (operand2 & 0xfff && fc > 0)
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
switch (fc) {
case 0:
vcpu->run->s.regs.gprs[0] = 3 << 28;
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
return 0;
case 1: /* same handling for 1 and 2 */
case 2:
mem = get_zeroed_page(GFP_KERNEL);
if (!mem)
goto out_fail;
if (stsi((void *) mem, fc, sel1, sel2))
goto out_mem;
break;
case 3:
if (sel1 != 2 || sel2 != 2)
goto out_fail;
mem = get_zeroed_page(GFP_KERNEL);
if (!mem)
goto out_fail;
handle_stsi_3_2_2(vcpu, (void *) mem);
break;
default:
goto out_fail;
}
if (copy_to_guest_absolute(vcpu, operand2, (void *) mem, PAGE_SIZE)) {
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
goto out_mem;
}
trace_kvm_s390_handle_stsi(vcpu, fc, sel1, sel2, operand2);
free_page(mem);
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
vcpu->run->s.regs.gprs[0] = 0;
return 0;
out_mem:
free_page(mem);
out_fail:
/* condition code 3 */
vcpu->arch.sie_block->gpsw.mask |= 3ul << 44;
return 0;
}
static const intercept_handler_t b2_handlers[256] = {
[0x02] = handle_stidp,
[0x10] = handle_set_prefix,
[0x11] = handle_store_prefix,
[0x12] = handle_store_cpu_address,
[0x29] = handle_skey,
[0x2a] = handle_skey,
[0x2b] = handle_skey,
[0x30] = handle_io_inst,
[0x31] = handle_io_inst,
[0x32] = handle_io_inst,
[0x33] = handle_io_inst,
[0x34] = handle_io_inst,
[0x35] = handle_io_inst,
[0x36] = handle_io_inst,
[0x37] = handle_io_inst,
[0x38] = handle_io_inst,
[0x39] = handle_io_inst,
[0x3a] = handle_io_inst,
[0x3b] = handle_io_inst,
[0x3c] = handle_io_inst,
[0x5f] = handle_io_inst,
[0x74] = handle_io_inst,
[0x76] = handle_io_inst,
[0x7d] = handle_stsi,
[0xb1] = handle_stfl,
[0xb2] = handle_lpswe,
};
int kvm_s390_handle_b2(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
/*
* a lot of B2 instructions are priviledged. We first check for
* the privileged ones, that we can handle in the kernel. If the
* kernel can handle this instruction, we check for the problem
* state bit and (a) handle the instruction or (b) send a code 2
* program check.
* Anything else goes to userspace.*/
handler = b2_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
if (handler) {
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
else
return handler(vcpu);
}
return -EOPNOTSUPP;
}
static int handle_epsw(struct kvm_vcpu *vcpu)
{
int reg1, reg2;
reg1 = (vcpu->arch.sie_block->ipb & 0x00f00000) >> 24;
reg2 = (vcpu->arch.sie_block->ipb & 0x000f0000) >> 16;
/* This basically extracts the mask half of the psw. */
vcpu->run->s.regs.gprs[reg1] &= 0xffffffff00000000;
vcpu->run->s.regs.gprs[reg1] |= vcpu->arch.sie_block->gpsw.mask >> 32;
if (reg2) {
vcpu->run->s.regs.gprs[reg2] &= 0xffffffff00000000;
vcpu->run->s.regs.gprs[reg2] |=
vcpu->arch.sie_block->gpsw.mask & 0x00000000ffffffff;
}
return 0;
}
static const intercept_handler_t b9_handlers[256] = {
[0x8d] = handle_epsw,
[0x9c] = handle_io_inst,
};
int kvm_s390_handle_b9(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
/* This is handled just as for the B2 instructions. */
handler = b9_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
if (handler) {
if ((handler != handle_epsw) &&
(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE))
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
else
return handler(vcpu);
}
return -EOPNOTSUPP;
}
static const intercept_handler_t eb_handlers[256] = {
[0x8a] = handle_io_inst,
};
int kvm_s390_handle_priv_eb(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
/* All eb instructions that end up here are privileged. */
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
handler = eb_handlers[vcpu->arch.sie_block->ipb & 0xff];
if (handler)
return handler(vcpu);
return -EOPNOTSUPP;
}
static int handle_tprot(struct kvm_vcpu *vcpu)
{
u64 address1, address2;
struct vm_area_struct *vma;
unsigned long user_address;
vcpu->stat.instruction_tprot++;
kvm_s390_get_base_disp_sse(vcpu, &address1, &address2);
/* we only handle the Linux memory detection case:
* access key == 0
* guest DAT == off
* everything else goes to userspace. */
if (address2 & 0xf0)
return -EOPNOTSUPP;
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_DAT)
return -EOPNOTSUPP;
down_read(&current->mm->mmap_sem);
user_address = __gmap_translate(address1, vcpu->arch.gmap);
if (IS_ERR_VALUE(user_address))
goto out_inject;
vma = find_vma(current->mm, user_address);
if (!vma)
goto out_inject;
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
if (!(vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_READ))
vcpu->arch.sie_block->gpsw.mask |= (1ul << 44);
if (!(vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_READ))
vcpu->arch.sie_block->gpsw.mask |= (2ul << 44);
up_read(&current->mm->mmap_sem);
return 0;
out_inject:
up_read(&current->mm->mmap_sem);
return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
}
int kvm_s390_handle_e5(struct kvm_vcpu *vcpu)
{
/* For e5xx... instructions we only handle TPROT */
if ((vcpu->arch.sie_block->ipa & 0x00ff) == 0x01)
return handle_tprot(vcpu);
return -EOPNOTSUPP;
}
static int handle_sckpf(struct kvm_vcpu *vcpu)
{
u32 value;
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
if (vcpu->run->s.regs.gprs[0] & 0x00000000ffff0000)
return kvm_s390_inject_program_int(vcpu,
PGM_SPECIFICATION);
value = vcpu->run->s.regs.gprs[0] & 0x000000000000ffff;
vcpu->arch.sie_block->todpr = value;
return 0;
}
static const intercept_handler_t x01_handlers[256] = {
[0x07] = handle_sckpf,
};
int kvm_s390_handle_01(struct kvm_vcpu *vcpu)
{
intercept_handler_t handler;
handler = x01_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
if (handler)
return handler(vcpu);
return -EOPNOTSUPP;
}
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