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gerrit-public.fairphone.software / kernel / msm-4.19 / b6b1f2d9cf796c3555734949b5e7a74fa2ceeb6c / . / arch / arm / kvm / coproc.c
blob: 2c14b69511e981816861e16b31ed18dce0f2360f [file] [log] [blame]
/*
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Authors: Rusty Russell <rusty@rustcorp.com.au>
* Christoffer Dall <c.dall@virtualopensystems.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/bsearch.h>
#include <linux/mm.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/kvm_mmu.h>
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include <trace/events/kvm.h>
#include <asm/vfp.h>
#include "../vfp/vfpinstr.h"
#include "trace.h"
#include "coproc.h"
/******************************************************************************
* Co-processor emulation
*****************************************************************************/
static bool write_to_read_only(struct kvm_vcpu *vcpu,
const struct coproc_params *params)
{
WARN_ONCE(1, "CP15 write to read-only register\n");
print_cp_instr(params);
kvm_inject_undefined(vcpu);
return false;
}
static bool read_from_write_only(struct kvm_vcpu *vcpu,
const struct coproc_params *params)
{
WARN_ONCE(1, "CP15 read to write-only register\n");
print_cp_instr(params);
kvm_inject_undefined(vcpu);
return false;
}
/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
static u32 cache_levels;
/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
#define CSSELR_MAX 12
/*
* kvm_vcpu_arch.cp15 holds cp15 registers as an array of u32, but some
* of cp15 registers can be viewed either as couple of two u32 registers
* or one u64 register. Current u64 register encoding is that least
* significant u32 word is followed by most significant u32 word.
*/
static inline void vcpu_cp15_reg64_set(struct kvm_vcpu *vcpu,
const struct coproc_reg *r,
u64 val)
{
vcpu_cp15(vcpu, r->reg) = val & 0xffffffff;
vcpu_cp15(vcpu, r->reg + 1) = val >> 32;
}
static inline u64 vcpu_cp15_reg64_get(struct kvm_vcpu *vcpu,
const struct coproc_reg *r)
{
u64 val;
val = vcpu_cp15(vcpu, r->reg + 1);
val = val << 32;
val = val | vcpu_cp15(vcpu, r->reg);
return val;
}
int kvm_handle_cp10_id(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
kvm_inject_undefined(vcpu);
return 1;
}
int kvm_handle_cp_0_13_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
/*
* We can get here, if the host has been built without VFPv3 support,
* but the guest attempted a floating point operation.
*/
kvm_inject_undefined(vcpu);
return 1;
}
int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
kvm_inject_undefined(vcpu);
return 1;
}
int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
kvm_inject_undefined(vcpu);
return 1;
}
static void reset_mpidr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
{
/*
* Compute guest MPIDR. We build a virtual cluster out of the
* vcpu_id, but we read the 'U' bit from the underlying
* hardware directly.
*/
vcpu_cp15(vcpu, c0_MPIDR) = ((read_cpuid_mpidr() & MPIDR_SMP_BITMASK) |
((vcpu->vcpu_id >> 2) << MPIDR_LEVEL_BITS) |
(vcpu->vcpu_id & 3));
}
/* TRM entries A7:4.3.31 A15:4.3.28 - RO WI */
static bool access_actlr(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (p->is_write)
return ignore_write(vcpu, p);
*vcpu_reg(vcpu, p->Rt1) = vcpu_cp15(vcpu, c1_ACTLR);
return true;
}
/* TRM entries A7:4.3.56, A15:4.3.60 - R/O. */
static bool access_cbar(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (p->is_write)
return write_to_read_only(vcpu, p);
return read_zero(vcpu, p);
}
/* TRM entries A7:4.3.49, A15:4.3.48 - R/O WI */
static bool access_l2ctlr(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (p->is_write)
return ignore_write(vcpu, p);
*vcpu_reg(vcpu, p->Rt1) = vcpu_cp15(vcpu, c9_L2CTLR);
return true;
}
static void reset_l2ctlr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
{
u32 l2ctlr, ncores;
asm volatile("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
l2ctlr &= ~(3 << 24);
ncores = atomic_read(&vcpu->kvm->online_vcpus) - 1;
/* How many cores in the current cluster and the next ones */
ncores -= (vcpu->vcpu_id & ~3);
/* Cap it to the maximum number of cores in a single cluster */
ncores = min(ncores, 3U);
l2ctlr |= (ncores & 3) << 24;
vcpu_cp15(vcpu, c9_L2CTLR) = l2ctlr;
}
static void reset_actlr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
{
u32 actlr;
/* ACTLR contains SMP bit: make sure you create all cpus first! */
asm volatile("mrc p15, 0, %0, c1, c0, 1\n" : "=r" (actlr));
/* Make the SMP bit consistent with the guest configuration */
if (atomic_read(&vcpu->kvm->online_vcpus) > 1)
actlr |= 1U << 6;
else
actlr &= ~(1U << 6);
vcpu_cp15(vcpu, c1_ACTLR) = actlr;
}
/*
* TRM entries: A7:4.3.50, A15:4.3.49
* R/O WI (even if NSACR.NS_L2ERR, a write of 1 is ignored).
*/
static bool access_l2ectlr(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (p->is_write)
return ignore_write(vcpu, p);
*vcpu_reg(vcpu, p->Rt1) = 0;
return true;
}
/*
* See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
*/
static bool access_dcsw(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (!p->is_write)
return read_from_write_only(vcpu, p);
kvm_set_way_flush(vcpu);
return true;
}
/*
* Generic accessor for VM registers. Only called as long as HCR_TVM
* is set. If the guest enables the MMU, we stop trapping the VM
* sys_regs and leave it in complete control of the caches.
*
* Used by the cpu-specific code.
*/
bool access_vm_reg(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
bool was_enabled = vcpu_has_cache_enabled(vcpu);
BUG_ON(!p->is_write);
vcpu_cp15(vcpu, r->reg) = *vcpu_reg(vcpu, p->Rt1);
if (p->is_64bit)
vcpu_cp15(vcpu, r->reg + 1) = *vcpu_reg(vcpu, p->Rt2);
kvm_toggle_cache(vcpu, was_enabled);
return true;
}
static bool access_gic_sgi(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
u64 reg;
if (!p->is_write)
return read_from_write_only(vcpu, p);
reg = (u64)*vcpu_reg(vcpu, p->Rt2) << 32;
reg |= *vcpu_reg(vcpu, p->Rt1) ;
vgic_v3_dispatch_sgi(vcpu, reg);
return true;
}
static bool access_gic_sre(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (p->is_write)
return ignore_write(vcpu, p);
*vcpu_reg(vcpu, p->Rt1) = vcpu->arch.vgic_cpu.vgic_v3.vgic_sre;
return true;
}
/*
* We could trap ID_DFR0 and tell the guest we don't support performance
* monitoring. Unfortunately the patch to make the kernel check ID_DFR0 was
* NAKed, so it will read the PMCR anyway.
*
* Therefore we tell the guest we have 0 counters. Unfortunately, we
* must always support PMCCNTR (the cycle counter): we just RAZ/WI for
* all PM registers, which doesn't crash the guest kernel at least.
*/
static bool pm_fake(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
const struct coproc_reg *r)
{
if (p->is_write)
return ignore_write(vcpu, p);
else
return read_zero(vcpu, p);
}
#define access_pmcr pm_fake
#define access_pmcntenset pm_fake
#define access_pmcntenclr pm_fake
#define access_pmovsr pm_fake
#define access_pmselr pm_fake
#define access_pmceid0 pm_fake
#define access_pmceid1 pm_fake
#define access_pmccntr pm_fake
#define access_pmxevtyper pm_fake
#define access_pmxevcntr pm_fake
#define access_pmuserenr pm_fake
#define access_pmintenset pm_fake
#define access_pmintenclr pm_fake
/* Architected CP15 registers.
* CRn denotes the primary register number, but is copied to the CRm in the
* user space API for 64-bit register access in line with the terminology used
* in the ARM ARM.
* Important: Must be sorted ascending by CRn, CRM, Op1, Op2 and with 64-bit
* registers preceding 32-bit ones.
*/
static const struct coproc_reg cp15_regs[] = {
/* MPIDR: we use VMPIDR for guest access. */
{ CRn( 0), CRm( 0), Op1( 0), Op2( 5), is32,
NULL, reset_mpidr, c0_MPIDR },
/* CSSELR: swapped by interrupt.S. */
{ CRn( 0), CRm( 0), Op1( 2), Op2( 0), is32,
NULL, reset_unknown, c0_CSSELR },
/* ACTLR: trapped by HCR.TAC bit. */
{ CRn( 1), CRm( 0), Op1( 0), Op2( 1), is32,
access_actlr, reset_actlr, c1_ACTLR },
/* CPACR: swapped by interrupt.S. */
{ CRn( 1), CRm( 0), Op1( 0), Op2( 2), is32,
NULL, reset_val, c1_CPACR, 0x00000000 },
/* TTBR0/TTBR1/TTBCR: swapped by interrupt.S. */
{ CRm64( 2), Op1( 0), is64, access_vm_reg, reset_unknown64, c2_TTBR0 },
{ CRn(2), CRm( 0), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c2_TTBR0 },
{ CRn(2), CRm( 0), Op1( 0), Op2( 1), is32,
access_vm_reg, reset_unknown, c2_TTBR1 },
{ CRn( 2), CRm( 0), Op1( 0), Op2( 2), is32,
access_vm_reg, reset_val, c2_TTBCR, 0x00000000 },
{ CRm64( 2), Op1( 1), is64, access_vm_reg, reset_unknown64, c2_TTBR1 },
/* DACR: swapped by interrupt.S. */
{ CRn( 3), CRm( 0), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c3_DACR },
/* DFSR/IFSR/ADFSR/AIFSR: swapped by interrupt.S. */
{ CRn( 5), CRm( 0), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c5_DFSR },
{ CRn( 5), CRm( 0), Op1( 0), Op2( 1), is32,
access_vm_reg, reset_unknown, c5_IFSR },
{ CRn( 5), CRm( 1), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c5_ADFSR },
{ CRn( 5), CRm( 1), Op1( 0), Op2( 1), is32,
access_vm_reg, reset_unknown, c5_AIFSR },
/* DFAR/IFAR: swapped by interrupt.S. */
{ CRn( 6), CRm( 0), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c6_DFAR },
{ CRn( 6), CRm( 0), Op1( 0), Op2( 2), is32,
access_vm_reg, reset_unknown, c6_IFAR },
/* PAR swapped by interrupt.S */
{ CRm64( 7), Op1( 0), is64, NULL, reset_unknown64, c7_PAR },
/*
* DC{C,I,CI}SW operations:
*/
{ CRn( 7), CRm( 6), Op1( 0), Op2( 2), is32, access_dcsw},
{ CRn( 7), CRm(10), Op1( 0), Op2( 2), is32, access_dcsw},
{ CRn( 7), CRm(14), Op1( 0), Op2( 2), is32, access_dcsw},
/*
* L2CTLR access (guest wants to know #CPUs).
*/
{ CRn( 9), CRm( 0), Op1( 1), Op2( 2), is32,
access_l2ctlr, reset_l2ctlr, c9_L2CTLR },
{ CRn( 9), CRm( 0), Op1( 1), Op2( 3), is32, access_l2ectlr},
/*
* Dummy performance monitor implementation.
*/
{ CRn( 9), CRm(12), Op1( 0), Op2( 0), is32, access_pmcr},
{ CRn( 9), CRm(12), Op1( 0), Op2( 1), is32, access_pmcntenset},
{ CRn( 9), CRm(12), Op1( 0), Op2( 2), is32, access_pmcntenclr},
{ CRn( 9), CRm(12), Op1( 0), Op2( 3), is32, access_pmovsr},
{ CRn( 9), CRm(12), Op1( 0), Op2( 5), is32, access_pmselr},
{ CRn( 9), CRm(12), Op1( 0), Op2( 6), is32, access_pmceid0},
{ CRn( 9), CRm(12), Op1( 0), Op2( 7), is32, access_pmceid1},
{ CRn( 9), CRm(13), Op1( 0), Op2( 0), is32, access_pmccntr},
{ CRn( 9), CRm(13), Op1( 0), Op2( 1), is32, access_pmxevtyper},
{ CRn( 9), CRm(13), Op1( 0), Op2( 2), is32, access_pmxevcntr},
{ CRn( 9), CRm(14), Op1( 0), Op2( 0), is32, access_pmuserenr},
{ CRn( 9), CRm(14), Op1( 0), Op2( 1), is32, access_pmintenset},
{ CRn( 9), CRm(14), Op1( 0), Op2( 2), is32, access_pmintenclr},
/* PRRR/NMRR (aka MAIR0/MAIR1): swapped by interrupt.S. */
{ CRn(10), CRm( 2), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c10_PRRR},
{ CRn(10), CRm( 2), Op1( 0), Op2( 1), is32,
access_vm_reg, reset_unknown, c10_NMRR},
/* AMAIR0/AMAIR1: swapped by interrupt.S. */
{ CRn(10), CRm( 3), Op1( 0), Op2( 0), is32,
access_vm_reg, reset_unknown, c10_AMAIR0},
{ CRn(10), CRm( 3), Op1( 0), Op2( 1), is32,
access_vm_reg, reset_unknown, c10_AMAIR1},
/* ICC_SGI1R */
{ CRm64(12), Op1( 0), is64, access_gic_sgi},
/* VBAR: swapped by interrupt.S. */
{ CRn(12), CRm( 0), Op1( 0), Op2( 0), is32,
NULL, reset_val, c12_VBAR, 0x00000000 },
/* ICC_SRE */
{ CRn(12), CRm(12), Op1( 0), Op2(5), is32, access_gic_sre },
/* CONTEXTIDR/TPIDRURW/TPIDRURO/TPIDRPRW: swapped by interrupt.S. */
{ CRn(13), CRm( 0), Op1( 0), Op2( 1), is32,
access_vm_reg, reset_val, c13_CID, 0x00000000 },
{ CRn(13), CRm( 0), Op1( 0), Op2( 2), is32,
NULL, reset_unknown, c13_TID_URW },
{ CRn(13), CRm( 0), Op1( 0), Op2( 3), is32,
NULL, reset_unknown, c13_TID_URO },
{ CRn(13), CRm( 0), Op1( 0), Op2( 4), is32,
NULL, reset_unknown, c13_TID_PRIV },
/* CNTKCTL: swapped by interrupt.S. */
{ CRn(14), CRm( 1), Op1( 0), Op2( 0), is32,
NULL, reset_val, c14_CNTKCTL, 0x00000000 },
/* The Configuration Base Address Register. */
{ CRn(15), CRm( 0), Op1( 4), Op2( 0), is32, access_cbar},
};
static int check_reg_table(const struct coproc_reg *table, unsigned int n)
{
unsigned int i;
for (i = 1; i < n; i++) {
if (cmp_reg(&table[i-1], &table[i]) >= 0) {
kvm_err("reg table %p out of order (%d)\n", table, i - 1);
return 1;
}
}
return 0;
}
/* Target specific emulation tables */
static struct kvm_coproc_target_table *target_tables[KVM_ARM_NUM_TARGETS];
void kvm_register_target_coproc_table(struct kvm_coproc_target_table *table)
{
BUG_ON(check_reg_table(table->table, table->num));
target_tables[table->target] = table;
}
/* Get specific register table for this target. */
static const struct coproc_reg *get_target_table(unsigned target, size_t *num)
{
struct kvm_coproc_target_table *table;
table = target_tables[target];
*num = table->num;
return table->table;
}
#define reg_to_match_value(x) \
({ \
unsigned long val; \
val = (x)->CRn << 11; \
val |= (x)->CRm << 7; \
val |= (x)->Op1 << 4; \
val |= (x)->Op2 << 1; \
val |= !(x)->is_64bit; \
val; \
})
static int match_reg(const void *key, const void *elt)
{
const unsigned long pval = (unsigned long)key;
const struct coproc_reg *r = elt;
return pval - reg_to_match_value(r);
}
static const struct coproc_reg *find_reg(const struct coproc_params *params,
const struct coproc_reg table[],
unsigned int num)
{
unsigned long pval = reg_to_match_value(params);
return bsearch((void *)pval, table, num, sizeof(table[0]), match_reg);
}
static int emulate_cp15(struct kvm_vcpu *vcpu,
const struct coproc_params *params)
{
size_t num;
const struct coproc_reg *table, *r;
trace_kvm_emulate_cp15_imp(params->Op1, params->Rt1, params->CRn,
params->CRm, params->Op2, params->is_write);
table = get_target_table(vcpu->arch.target, &num);
/* Search target-specific then generic table. */
r = find_reg(params, table, num);
if (!r)
r = find_reg(params, cp15_regs, ARRAY_SIZE(cp15_regs));
if (likely(r)) {
/* If we don't have an accessor, we should never get here! */
BUG_ON(!r->access);
if (likely(r->access(vcpu, params, r))) {
/* Skip instruction, since it was emulated */
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
}
} else {
/* If access function fails, it should complain. */
kvm_err("Unsupported guest CP15 access at: %08lx\n",
*vcpu_pc(vcpu));
print_cp_instr(params);
kvm_inject_undefined(vcpu);
}
return 1;
}
/**
* kvm_handle_cp15_64 -- handles a mrrc/mcrr trap on a guest CP15 access
* @vcpu: The VCPU pointer
* @run: The kvm_run struct
*/
int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
struct coproc_params params;
params.CRn = (kvm_vcpu_get_hsr(vcpu) >> 1) & 0xf;
params.Rt1 = (kvm_vcpu_get_hsr(vcpu) >> 5) & 0xf;
params.is_write = ((kvm_vcpu_get_hsr(vcpu) & 1) == 0);
params.is_64bit = true;
params.Op1 = (kvm_vcpu_get_hsr(vcpu) >> 16) & 0xf;
params.Op2 = 0;
params.Rt2 = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
params.CRm = 0;
return emulate_cp15(vcpu, &params);
}
static void reset_coproc_regs(struct kvm_vcpu *vcpu,
const struct coproc_reg *table, size_t num)
{
unsigned long i;
for (i = 0; i < num; i++)
if (table[i].reset)
table[i].reset(vcpu, &table[i]);
}
/**
* kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15 access
* @vcpu: The VCPU pointer
* @run: The kvm_run struct
*/
int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
struct coproc_params params;
params.CRm = (kvm_vcpu_get_hsr(vcpu) >> 1) & 0xf;
params.Rt1 = (kvm_vcpu_get_hsr(vcpu) >> 5) & 0xf;
params.is_write = ((kvm_vcpu_get_hsr(vcpu) & 1) == 0);
params.is_64bit = false;
params.CRn = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
params.Op1 = (kvm_vcpu_get_hsr(vcpu) >> 14) & 0x7;
params.Op2 = (kvm_vcpu_get_hsr(vcpu) >> 17) & 0x7;
params.Rt2 = 0;
return emulate_cp15(vcpu, &params);
}
/******************************************************************************
* Userspace API
*****************************************************************************/
static bool index_to_params(u64 id, struct coproc_params *params)
{
switch (id & KVM_REG_SIZE_MASK) {
case KVM_REG_SIZE_U32:
/* Any unused index bits means it's not valid. */
if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
| KVM_REG_ARM_COPROC_MASK
| KVM_REG_ARM_32_CRN_MASK
| KVM_REG_ARM_CRM_MASK
| KVM_REG_ARM_OPC1_MASK
| KVM_REG_ARM_32_OPC2_MASK))
return false;
params->is_64bit = false;
params->CRn = ((id & KVM_REG_ARM_32_CRN_MASK)
>> KVM_REG_ARM_32_CRN_SHIFT);
params->CRm = ((id & KVM_REG_ARM_CRM_MASK)
>> KVM_REG_ARM_CRM_SHIFT);
params->Op1 = ((id & KVM_REG_ARM_OPC1_MASK)
>> KVM_REG_ARM_OPC1_SHIFT);
params->Op2 = ((id & KVM_REG_ARM_32_OPC2_MASK)
>> KVM_REG_ARM_32_OPC2_SHIFT);
return true;
case KVM_REG_SIZE_U64:
/* Any unused index bits means it's not valid. */
if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
| KVM_REG_ARM_COPROC_MASK
| KVM_REG_ARM_CRM_MASK
| KVM_REG_ARM_OPC1_MASK))
return false;
params->is_64bit = true;
/* CRm to CRn: see cp15_to_index for details */
params->CRn = ((id & KVM_REG_ARM_CRM_MASK)
>> KVM_REG_ARM_CRM_SHIFT);
params->Op1 = ((id & KVM_REG_ARM_OPC1_MASK)
>> KVM_REG_ARM_OPC1_SHIFT);
params->Op2 = 0;
params->CRm = 0;
return true;
default:
return false;
}
}
/* Decode an index value, and find the cp15 coproc_reg entry. */
static const struct coproc_reg *index_to_coproc_reg(struct kvm_vcpu *vcpu,
u64 id)
{
size_t num;
const struct coproc_reg *table, *r;
struct coproc_params params;
/* We only do cp15 for now. */
if ((id & KVM_REG_ARM_COPROC_MASK) >> KVM_REG_ARM_COPROC_SHIFT != 15)
return NULL;
if (!index_to_params(id, &params))
return NULL;
table = get_target_table(vcpu->arch.target, &num);
r = find_reg(&params, table, num);
if (!r)
r = find_reg(&params, cp15_regs, ARRAY_SIZE(cp15_regs));
/* Not saved in the cp15 array? */
if (r && !r->reg)
r = NULL;
return r;
}
/*
* These are the invariant cp15 registers: we let the guest see the host
* versions of these, so they're part of the guest state.
*
* A future CPU may provide a mechanism to present different values to
* the guest, or a future kvm may trap them.
*/
/* Unfortunately, there's no register-argument for mrc, so generate. */
#define FUNCTION_FOR32(crn, crm, op1, op2, name) \
static void get_##name(struct kvm_vcpu *v, \
const struct coproc_reg *r) \
{ \
u32 val; \
\
asm volatile("mrc p15, " __stringify(op1) \
", %0, c" __stringify(crn) \
", c" __stringify(crm) \
", " __stringify(op2) "\n" : "=r" (val)); \
((struct coproc_reg *)r)->val = val; \
}
FUNCTION_FOR32(0, 0, 0, 0, MIDR)
FUNCTION_FOR32(0, 0, 0, 1, CTR)
FUNCTION_FOR32(0, 0, 0, 2, TCMTR)
FUNCTION_FOR32(0, 0, 0, 3, TLBTR)
FUNCTION_FOR32(0, 0, 0, 6, REVIDR)
FUNCTION_FOR32(0, 1, 0, 0, ID_PFR0)
FUNCTION_FOR32(0, 1, 0, 1, ID_PFR1)
FUNCTION_FOR32(0, 1, 0, 2, ID_DFR0)
FUNCTION_FOR32(0, 1, 0, 3, ID_AFR0)
FUNCTION_FOR32(0, 1, 0, 4, ID_MMFR0)
FUNCTION_FOR32(0, 1, 0, 5, ID_MMFR1)
FUNCTION_FOR32(0, 1, 0, 6, ID_MMFR2)
FUNCTION_FOR32(0, 1, 0, 7, ID_MMFR3)
FUNCTION_FOR32(0, 2, 0, 0, ID_ISAR0)
FUNCTION_FOR32(0, 2, 0, 1, ID_ISAR1)
FUNCTION_FOR32(0, 2, 0, 2, ID_ISAR2)
FUNCTION_FOR32(0, 2, 0, 3, ID_ISAR3)
FUNCTION_FOR32(0, 2, 0, 4, ID_ISAR4)
FUNCTION_FOR32(0, 2, 0, 5, ID_ISAR5)
FUNCTION_FOR32(0, 0, 1, 1, CLIDR)
FUNCTION_FOR32(0, 0, 1, 7, AIDR)
/* ->val is filled in by kvm_invariant_coproc_table_init() */
static struct coproc_reg invariant_cp15[] = {
{ CRn( 0), CRm( 0), Op1( 0), Op2( 0), is32, NULL, get_MIDR },
{ CRn( 0), CRm( 0), Op1( 0), Op2( 1), is32, NULL, get_CTR },
{ CRn( 0), CRm( 0), Op1( 0), Op2( 2), is32, NULL, get_TCMTR },
{ CRn( 0), CRm( 0), Op1( 0), Op2( 3), is32, NULL, get_TLBTR },
{ CRn( 0), CRm( 0), Op1( 0), Op2( 6), is32, NULL, get_REVIDR },
{ CRn( 0), CRm( 0), Op1( 1), Op2( 1), is32, NULL, get_CLIDR },
{ CRn( 0), CRm( 0), Op1( 1), Op2( 7), is32, NULL, get_AIDR },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 0), is32, NULL, get_ID_PFR0 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 1), is32, NULL, get_ID_PFR1 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 2), is32, NULL, get_ID_DFR0 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 3), is32, NULL, get_ID_AFR0 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 4), is32, NULL, get_ID_MMFR0 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 5), is32, NULL, get_ID_MMFR1 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 6), is32, NULL, get_ID_MMFR2 },
{ CRn( 0), CRm( 1), Op1( 0), Op2( 7), is32, NULL, get_ID_MMFR3 },
{ CRn( 0), CRm( 2), Op1( 0), Op2( 0), is32, NULL, get_ID_ISAR0 },
{ CRn( 0), CRm( 2), Op1( 0), Op2( 1), is32, NULL, get_ID_ISAR1 },
{ CRn( 0), CRm( 2), Op1( 0), Op2( 2), is32, NULL, get_ID_ISAR2 },
{ CRn( 0), CRm( 2), Op1( 0), Op2( 3), is32, NULL, get_ID_ISAR3 },
{ CRn( 0), CRm( 2), Op1( 0), Op2( 4), is32, NULL, get_ID_ISAR4 },
{ CRn( 0), CRm( 2), Op1( 0), Op2( 5), is32, NULL, get_ID_ISAR5 },
};
/*
* Reads a register value from a userspace address to a kernel
* variable. Make sure that register size matches sizeof(*__val).
*/
static int reg_from_user(void *val, const void __user *uaddr, u64 id)
{
if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
return -EFAULT;
return 0;
}
/*
* Writes a register value to a userspace address from a kernel variable.
* Make sure that register size matches sizeof(*__val).
*/
static int reg_to_user(void __user *uaddr, const void *val, u64 id)
{
if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
return -EFAULT;
return 0;
}
static int get_invariant_cp15(u64 id, void __user *uaddr)
{
struct coproc_params params;
const struct coproc_reg *r;
int ret;
if (!index_to_params(id, &params))
return -ENOENT;
r = find_reg(&params, invariant_cp15, ARRAY_SIZE(invariant_cp15));
if (!r)
return -ENOENT;
ret = -ENOENT;
if (KVM_REG_SIZE(id) == 4) {
u32 val = r->val;
ret = reg_to_user(uaddr, &val, id);
} else if (KVM_REG_SIZE(id) == 8) {
ret = reg_to_user(uaddr, &r->val, id);
}
return ret;
}
static int set_invariant_cp15(u64 id, void __user *uaddr)
{
struct coproc_params params;
const struct coproc_reg *r;
int err;
u64 val;
if (!index_to_params(id, &params))
return -ENOENT;
r = find_reg(&params, invariant_cp15, ARRAY_SIZE(invariant_cp15));
if (!r)
return -ENOENT;
err = -ENOENT;
if (KVM_REG_SIZE(id) == 4) {
u32 val32;
err = reg_from_user(&val32, uaddr, id);
if (!err)
val = val32;
} else if (KVM_REG_SIZE(id) == 8) {
err = reg_from_user(&val, uaddr, id);
}
if (err)
return err;
/* This is what we mean by invariant: you can't change it. */
if (r->val != val)
return -EINVAL;
return 0;
}
static bool is_valid_cache(u32 val)
{
u32 level, ctype;
if (val >= CSSELR_MAX)
return false;
/* Bottom bit is Instruction or Data bit. Next 3 bits are level. */
level = (val >> 1);
ctype = (cache_levels >> (level * 3)) & 7;
switch (ctype) {
case 0: /* No cache */
return false;
case 1: /* Instruction cache only */
return (val & 1);
case 2: /* Data cache only */
case 4: /* Unified cache */
return !(val & 1);
case 3: /* Separate instruction and data caches */
return true;
default: /* Reserved: we can't know instruction or data. */
return false;
}
}
/* Which cache CCSIDR represents depends on CSSELR value. */
static u32 get_ccsidr(u32 csselr)
{
u32 ccsidr;
/* Make sure noone else changes CSSELR during this! */
local_irq_disable();
/* Put value into CSSELR */
asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (csselr));
isb();
/* Read result out of CCSIDR */
asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (ccsidr));
local_irq_enable();
return ccsidr;
}
static int demux_c15_get(u64 id, void __user *uaddr)
{
u32 val;
u32 __user *uval = uaddr;
/* Fail if we have unknown bits set. */
if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
| ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
return -ENOENT;
switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
case KVM_REG_ARM_DEMUX_ID_CCSIDR:
if (KVM_REG_SIZE(id) != 4)
return -ENOENT;
val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
>> KVM_REG_ARM_DEMUX_VAL_SHIFT;
if (!is_valid_cache(val))
return -ENOENT;
return put_user(get_ccsidr(val), uval);
default:
return -ENOENT;
}
}
static int demux_c15_set(u64 id, void __user *uaddr)
{
u32 val, newval;
u32 __user *uval = uaddr;
/* Fail if we have unknown bits set. */
if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
| ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
return -ENOENT;
switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
case KVM_REG_ARM_DEMUX_ID_CCSIDR:
if (KVM_REG_SIZE(id) != 4)
return -ENOENT;
val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
>> KVM_REG_ARM_DEMUX_VAL_SHIFT;
if (!is_valid_cache(val))
return -ENOENT;
if (get_user(newval, uval))
return -EFAULT;
/* This is also invariant: you can't change it. */
if (newval != get_ccsidr(val))
return -EINVAL;
return 0;
default:
return -ENOENT;
}
}
#ifdef CONFIG_VFPv3
static const int vfp_sysregs[] = { KVM_REG_ARM_VFP_FPEXC,
KVM_REG_ARM_VFP_FPSCR,
KVM_REG_ARM_VFP_FPINST,
KVM_REG_ARM_VFP_FPINST2,
KVM_REG_ARM_VFP_MVFR0,
KVM_REG_ARM_VFP_MVFR1,
KVM_REG_ARM_VFP_FPSID };
static unsigned int num_fp_regs(void)
{
if (((fmrx(MVFR0) & MVFR0_A_SIMD_MASK) >> MVFR0_A_SIMD_BIT) == 2)
return 32;
else
return 16;
}
static unsigned int num_vfp_regs(void)
{
/* Normal FP regs + control regs. */
return num_fp_regs() + ARRAY_SIZE(vfp_sysregs);
}
static int copy_vfp_regids(u64 __user *uindices)
{
unsigned int i;
const u64 u32reg = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP;
const u64 u64reg = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;
for (i = 0; i < num_fp_regs(); i++) {
if (put_user((u64reg | KVM_REG_ARM_VFP_BASE_REG) + i,
uindices))
return -EFAULT;
uindices++;
}
for (i = 0; i < ARRAY_SIZE(vfp_sysregs); i++) {
if (put_user(u32reg | vfp_sysregs[i], uindices))
return -EFAULT;
uindices++;
}
return num_vfp_regs();
}
static int vfp_get_reg(const struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
u32 vfpid = (id & KVM_REG_ARM_VFP_MASK);
u32 val;
/* Fail if we have unknown bits set. */
if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
| ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
return -ENOENT;
if (vfpid < num_fp_regs()) {
if (KVM_REG_SIZE(id) != 8)
return -ENOENT;
return reg_to_user(uaddr, &vcpu->arch.ctxt.vfp.fpregs[vfpid],
id);
}
/* FP control registers are all 32 bit. */
if (KVM_REG_SIZE(id) != 4)
return -ENOENT;
switch (vfpid) {
case KVM_REG_ARM_VFP_FPEXC:
return reg_to_user(uaddr, &vcpu->arch.ctxt.vfp.fpexc, id);
case KVM_REG_ARM_VFP_FPSCR:
return reg_to_user(uaddr, &vcpu->arch.ctxt.vfp.fpscr, id);
case KVM_REG_ARM_VFP_FPINST:
return reg_to_user(uaddr, &vcpu->arch.ctxt.vfp.fpinst, id);
case KVM_REG_ARM_VFP_FPINST2:
return reg_to_user(uaddr, &vcpu->arch.ctxt.vfp.fpinst2, id);
case KVM_REG_ARM_VFP_MVFR0:
val = fmrx(MVFR0);
return reg_to_user(uaddr, &val, id);
case KVM_REG_ARM_VFP_MVFR1:
val = fmrx(MVFR1);
return reg_to_user(uaddr, &val, id);
case KVM_REG_ARM_VFP_FPSID:
val = fmrx(FPSID);
return reg_to_user(uaddr, &val, id);
default:
return -ENOENT;
}
}
static int vfp_set_reg(struct kvm_vcpu *vcpu, u64 id, const void __user *uaddr)
{
u32 vfpid = (id & KVM_REG_ARM_VFP_MASK);
u32 val;
/* Fail if we have unknown bits set. */
if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
| ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
return -ENOENT;
if (vfpid < num_fp_regs()) {
if (KVM_REG_SIZE(id) != 8)
return -ENOENT;
return reg_from_user(&vcpu->arch.ctxt.vfp.fpregs[vfpid],
uaddr, id);
}
/* FP control registers are all 32 bit. */
if (KVM_REG_SIZE(id) != 4)
return -ENOENT;
switch (vfpid) {
case KVM_REG_ARM_VFP_FPEXC:
return reg_from_user(&vcpu->arch.ctxt.vfp.fpexc, uaddr, id);
case KVM_REG_ARM_VFP_FPSCR:
return reg_from_user(&vcpu->arch.ctxt.vfp.fpscr, uaddr, id);
case KVM_REG_ARM_VFP_FPINST:
return reg_from_user(&vcpu->arch.ctxt.vfp.fpinst, uaddr, id);
case KVM_REG_ARM_VFP_FPINST2:
return reg_from_user(&vcpu->arch.ctxt.vfp.fpinst2, uaddr, id);
/* These are invariant. */
case KVM_REG_ARM_VFP_MVFR0:
if (reg_from_user(&val, uaddr, id))
return -EFAULT;
if (val != fmrx(MVFR0))
return -EINVAL;
return 0;
case KVM_REG_ARM_VFP_MVFR1:
if (reg_from_user(&val, uaddr, id))
return -EFAULT;
if (val != fmrx(MVFR1))
return -EINVAL;
return 0;
case KVM_REG_ARM_VFP_FPSID:
if (reg_from_user(&val, uaddr, id))
return -EFAULT;
if (val != fmrx(FPSID))
return -EINVAL;
return 0;
default:
return -ENOENT;
}
}
#else /* !CONFIG_VFPv3 */
static unsigned int num_vfp_regs(void)
{
return 0;
}
static int copy_vfp_regids(u64 __user *uindices)
{
return 0;
}
static int vfp_get_reg(const struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
return -ENOENT;
}
static int vfp_set_reg(struct kvm_vcpu *vcpu, u64 id, const void __user *uaddr)
{
return -ENOENT;
}
#endif /* !CONFIG_VFPv3 */
int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct coproc_reg *r;
void __user *uaddr = (void __user *)(long)reg->addr;
int ret;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_get(reg->id, uaddr);
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_VFP)
return vfp_get_reg(vcpu, reg->id, uaddr);
r = index_to_coproc_reg(vcpu, reg->id);
if (!r)
return get_invariant_cp15(reg->id, uaddr);
ret = -ENOENT;
if (KVM_REG_SIZE(reg->id) == 8) {
u64 val;
val = vcpu_cp15_reg64_get(vcpu, r);
ret = reg_to_user(uaddr, &val, reg->id);
} else if (KVM_REG_SIZE(reg->id) == 4) {
ret = reg_to_user(uaddr, &vcpu_cp15(vcpu, r->reg), reg->id);
}
return ret;
}
int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct coproc_reg *r;
void __user *uaddr = (void __user *)(long)reg->addr;
int ret;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_set(reg->id, uaddr);
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_VFP)
return vfp_set_reg(vcpu, reg->id, uaddr);
r = index_to_coproc_reg(vcpu, reg->id);
if (!r)
return set_invariant_cp15(reg->id, uaddr);
ret = -ENOENT;
if (KVM_REG_SIZE(reg->id) == 8) {
u64 val;
ret = reg_from_user(&val, uaddr, reg->id);
if (!ret)
vcpu_cp15_reg64_set(vcpu, r, val);
} else if (KVM_REG_SIZE(reg->id) == 4) {
ret = reg_from_user(&vcpu_cp15(vcpu, r->reg), uaddr, reg->id);
}
return ret;
}
static unsigned int num_demux_regs(void)
{
unsigned int i, count = 0;
for (i = 0; i < CSSELR_MAX; i++)
if (is_valid_cache(i))
count++;
return count;
}
static int write_demux_regids(u64 __user *uindices)
{
u64 val = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX;
unsigned int i;
val |= KVM_REG_ARM_DEMUX_ID_CCSIDR;
for (i = 0; i < CSSELR_MAX; i++) {
if (!is_valid_cache(i))
continue;
if (put_user(val | i, uindices))
return -EFAULT;
uindices++;
}
return 0;
}
static u64 cp15_to_index(const struct coproc_reg *reg)
{
u64 val = KVM_REG_ARM | (15 << KVM_REG_ARM_COPROC_SHIFT);
if (reg->is_64bit) {
val |= KVM_REG_SIZE_U64;
val |= (reg->Op1 << KVM_REG_ARM_OPC1_SHIFT);
/*
* CRn always denotes the primary coproc. reg. nr. for the
* in-kernel representation, but the user space API uses the
* CRm for the encoding, because it is modelled after the
* MRRC/MCRR instructions: see the ARM ARM rev. c page
* B3-1445
*/
val |= (reg->CRn << KVM_REG_ARM_CRM_SHIFT);
} else {
val |= KVM_REG_SIZE_U32;
val |= (reg->Op1 << KVM_REG_ARM_OPC1_SHIFT);
val |= (reg->Op2 << KVM_REG_ARM_32_OPC2_SHIFT);
val |= (reg->CRm << KVM_REG_ARM_CRM_SHIFT);
val |= (reg->CRn << KVM_REG_ARM_32_CRN_SHIFT);
}
return val;
}
static bool copy_reg_to_user(const struct coproc_reg *reg, u64 __user **uind)
{
if (!*uind)
return true;
if (put_user(cp15_to_index(reg), *uind))
return false;
(*uind)++;
return true;
}
/* Assumed ordered tables, see kvm_coproc_table_init. */
static int walk_cp15(struct kvm_vcpu *vcpu, u64 __user *uind)
{
const struct coproc_reg *i1, *i2, *end1, *end2;
unsigned int total = 0;
size_t num;
/* We check for duplicates here, to allow arch-specific overrides. */
i1 = get_target_table(vcpu->arch.target, &num);
end1 = i1 + num;
i2 = cp15_regs;
end2 = cp15_regs + ARRAY_SIZE(cp15_regs);
BUG_ON(i1 == end1 || i2 == end2);
/* Walk carefully, as both tables may refer to the same register. */
while (i1 || i2) {
int cmp = cmp_reg(i1, i2);
/* target-specific overrides generic entry. */
if (cmp <= 0) {
/* Ignore registers we trap but don't save. */
if (i1->reg) {
if (!copy_reg_to_user(i1, &uind))
return -EFAULT;
total++;
}
} else {
/* Ignore registers we trap but don't save. */
if (i2->reg) {
if (!copy_reg_to_user(i2, &uind))
return -EFAULT;
total++;
}
}
if (cmp <= 0 && ++i1 == end1)
i1 = NULL;
if (cmp >= 0 && ++i2 == end2)
i2 = NULL;
}
return total;
}
unsigned long kvm_arm_num_coproc_regs(struct kvm_vcpu *vcpu)
{
return ARRAY_SIZE(invariant_cp15)
+ num_demux_regs()
+ num_vfp_regs()
+ walk_cp15(vcpu, (u64 __user *)NULL);
}
int kvm_arm_copy_coproc_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
unsigned int i;
int err;
/* Then give them all the invariant registers' indices. */
for (i = 0; i < ARRAY_SIZE(invariant_cp15); i++) {
if (put_user(cp15_to_index(&invariant_cp15[i]), uindices))
return -EFAULT;
uindices++;
}
err = walk_cp15(vcpu, uindices);
if (err < 0)
return err;
uindices += err;
err = copy_vfp_regids(uindices);
if (err < 0)
return err;
uindices += err;
return write_demux_regids(uindices);
}
void kvm_coproc_table_init(void)
{
unsigned int i;
/* Make sure tables are unique and in order. */
BUG_ON(check_reg_table(cp15_regs, ARRAY_SIZE(cp15_regs)));
BUG_ON(check_reg_table(invariant_cp15, ARRAY_SIZE(invariant_cp15)));
/* We abuse the reset function to overwrite the table itself. */
for (i = 0; i < ARRAY_SIZE(invariant_cp15); i++)
invariant_cp15[i].reset(NULL, &invariant_cp15[i]);
/*
* CLIDR format is awkward, so clean it up. See ARM B4.1.20:
*
* If software reads the Cache Type fields from Ctype1
* upwards, once it has seen a value of 0b000, no caches
* exist at further-out levels of the hierarchy. So, for
* example, if Ctype3 is the first Cache Type field with a
* value of 0b000, the values of Ctype4 to Ctype7 must be
* ignored.
*/
asm volatile("mrc p15, 1, %0, c0, c0, 1" : "=r" (cache_levels));
for (i = 0; i < 7; i++)
if (((cache_levels >> (i*3)) & 7) == 0)
break;
/* Clear all higher bits. */
cache_levels &= (1 << (i*3))-1;
}
/**
* kvm_reset_coprocs - sets cp15 registers to reset value
* @vcpu: The VCPU pointer
*
* This function finds the right table above and sets the registers on the
* virtual CPU struct to their architecturally defined reset values.
*/
void kvm_reset_coprocs(struct kvm_vcpu *vcpu)
{
size_t num;
const struct coproc_reg *table;
/* Catch someone adding a register without putting in reset entry. */
memset(vcpu->arch.ctxt.cp15, 0x42, sizeof(vcpu->arch.ctxt.cp15));
/* Generic chip reset first (so target could override). */
reset_coproc_regs(vcpu, cp15_regs, ARRAY_SIZE(cp15_regs));
table = get_target_table(vcpu->arch.target, &num);
reset_coproc_regs(vcpu, table, num);
for (num = 1; num < NR_CP15_REGS; num++)
if (vcpu_cp15(vcpu, num) == 0x42424242)
panic("Didn't reset vcpu_cp15(vcpu, %zi)", num);
}