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kernel-ark/arch/arm64/kvm/sys_regs.c
Marc Zyngier 9d218a1fcf arm64: KVM: flush VM pages before letting the guest enable caches 
When the guest runs with caches disabled (like in an early boot
sequence, for example), all the writes are diectly going to RAM,
bypassing the caches altogether.

Once the MMU and caches are enabled, whatever sits in the cache
becomes suddenly visible, which isn't what the guest expects.

A way to avoid this potential disaster is to invalidate the cache
when the MMU is being turned on. For this, we hook into the SCTLR_EL1
trapping code, and scan the stage-2 page tables, invalidating the
pages/sections that have already been mapped in.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-03-03 01:15:22 +00:00

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/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* Derived from arch/arm/kvm/coproc.c:
* 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, see <http://www.gnu.org/licenses/>.
*/
#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 "sys_regs.h"
/*
* All of this file is extremly similar to the ARM coproc.c, but the
* types are different. My gut feeling is that it should be pretty
* easy to merge, but that would be an ABI breakage -- again. VFP
* would also need to be abstracted.
*
* For AArch32, we only take care of what is being trapped. Anything
* that has to do with init and userspace access has to go via the
* 64bit interface.
*/
/* 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
/* 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("msr csselr_el1, %x0" : : "r" (csselr));
isb();
/* Read result out of CCSIDR */
asm volatile("mrs %0, ccsidr_el1" : "=r" (ccsidr));
local_irq_enable();
return ccsidr;
}
static void do_dc_cisw(u32 val)
{
asm volatile("dc cisw, %x0" : : "r" (val));
dsb();
}
static void do_dc_csw(u32 val)
{
asm volatile("dc csw, %x0" : : "r" (val));
dsb();
}
/* See note at ARM ARM B1.14.4 */
static bool access_dcsw(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
unsigned long val;
int cpu;
if (!p->is_write)
return read_from_write_only(vcpu, p);
cpu = get_cpu();
cpumask_setall(&vcpu->arch.require_dcache_flush);
cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
/* If we were already preempted, take the long way around */
if (cpu != vcpu->arch.last_pcpu) {
flush_cache_all();
goto done;
}
val = *vcpu_reg(vcpu, p->Rt);
switch (p->CRm) {
case 6: /* Upgrade DCISW to DCCISW, as per HCR.SWIO */
case 14: /* DCCISW */
do_dc_cisw(val);
break;
case 10: /* DCCSW */
do_dc_csw(val);
break;
}
done:
put_cpu();
return true;
}
/*
* Generic accessor for VM registers. Only called as long as HCR_TVM
* is set.
*/
static bool access_vm_reg(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
unsigned long val;
BUG_ON(!p->is_write);
val = *vcpu_reg(vcpu, p->Rt);
if (!p->is_aarch32) {
vcpu_sys_reg(vcpu, r->reg) = val;
} else {
vcpu_cp15(vcpu, r->reg) = val & 0xffffffffUL;
if (!p->is_32bit)
vcpu_cp15(vcpu, r->reg + 1) = val >> 32;
}
return true;
}
/*
* SCTLR_EL1 accessor. 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.
*/
static bool access_sctlr(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
access_vm_reg(vcpu, p, r);
if (vcpu_has_cache_enabled(vcpu)) { /* MMU+Caches enabled? */
vcpu->arch.hcr_el2 &= ~HCR_TVM;
stage2_flush_vm(vcpu->kvm);
}
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 sys_reg_params *p,
const struct sys_reg_desc *r)
{
if (p->is_write)
return ignore_write(vcpu, p);
else
return read_zero(vcpu, p);
}
static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 amair;
asm volatile("mrs %0, amair_el1\n" : "=r" (amair));
vcpu_sys_reg(vcpu, AMAIR_EL1) = amair;
}
static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
/*
* Simply map the vcpu_id into the Aff0 field of the MPIDR.
*/
vcpu_sys_reg(vcpu, MPIDR_EL1) = (1UL << 31) | (vcpu->vcpu_id & 0xff);
}
/*
* Architected system registers.
* Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
*/
static const struct sys_reg_desc sys_reg_descs[] = {
/* DC ISW */
{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b0110), Op2(0b010),
access_dcsw },
/* DC CSW */
{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1010), Op2(0b010),
access_dcsw },
/* DC CISW */
{ Op0(0b01), Op1(0b000), CRn(0b0111), CRm(0b1110), Op2(0b010),
access_dcsw },
/* TEECR32_EL1 */
{ Op0(0b10), Op1(0b010), CRn(0b0000), CRm(0b0000), Op2(0b000),
NULL, reset_val, TEECR32_EL1, 0 },
/* TEEHBR32_EL1 */
{ Op0(0b10), Op1(0b010), CRn(0b0001), CRm(0b0000), Op2(0b000),
NULL, reset_val, TEEHBR32_EL1, 0 },
/* DBGVCR32_EL2 */
{ Op0(0b10), Op1(0b100), CRn(0b0000), CRm(0b0111), Op2(0b000),
NULL, reset_val, DBGVCR32_EL2, 0 },
/* MPIDR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b101),
NULL, reset_mpidr, MPIDR_EL1 },
/* SCTLR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b000),
access_sctlr, reset_val, SCTLR_EL1, 0x00C50078 },
/* CPACR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b010),
NULL, reset_val, CPACR_EL1, 0 },
/* TTBR0_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b000),
access_vm_reg, reset_unknown, TTBR0_EL1 },
/* TTBR1_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b001),
access_vm_reg, reset_unknown, TTBR1_EL1 },
/* TCR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0010), CRm(0b0000), Op2(0b010),
access_vm_reg, reset_val, TCR_EL1, 0 },
/* AFSR0_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b000),
access_vm_reg, reset_unknown, AFSR0_EL1 },
/* AFSR1_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0001), Op2(0b001),
access_vm_reg, reset_unknown, AFSR1_EL1 },
/* ESR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0101), CRm(0b0010), Op2(0b000),
access_vm_reg, reset_unknown, ESR_EL1 },
/* FAR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0110), CRm(0b0000), Op2(0b000),
access_vm_reg, reset_unknown, FAR_EL1 },
/* PAR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0111), CRm(0b0100), Op2(0b000),
NULL, reset_unknown, PAR_EL1 },
/* PMINTENSET_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b001),
pm_fake },
/* PMINTENCLR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1001), CRm(0b1110), Op2(0b010),
pm_fake },
/* MAIR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0010), Op2(0b000),
access_vm_reg, reset_unknown, MAIR_EL1 },
/* AMAIR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1010), CRm(0b0011), Op2(0b000),
access_vm_reg, reset_amair_el1, AMAIR_EL1 },
/* VBAR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000),
NULL, reset_val, VBAR_EL1, 0 },
/* CONTEXTIDR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b001),
access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
/* TPIDR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b100),
NULL, reset_unknown, TPIDR_EL1 },
/* CNTKCTL_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b1110), CRm(0b0001), Op2(0b000),
NULL, reset_val, CNTKCTL_EL1, 0},
/* CSSELR_EL1 */
{ Op0(0b11), Op1(0b010), CRn(0b0000), CRm(0b0000), Op2(0b000),
NULL, reset_unknown, CSSELR_EL1 },
/* PMCR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b000),
pm_fake },
/* PMCNTENSET_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b001),
pm_fake },
/* PMCNTENCLR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b010),
pm_fake },
/* PMOVSCLR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b011),
pm_fake },
/* PMSWINC_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b100),
pm_fake },
/* PMSELR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b101),
pm_fake },
/* PMCEID0_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
pm_fake },
/* PMCEID1_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
pm_fake },
/* PMCCNTR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
pm_fake },
/* PMXEVTYPER_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b001),
pm_fake },
/* PMXEVCNTR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b010),
pm_fake },
/* PMUSERENR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b000),
pm_fake },
/* PMOVSSET_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
pm_fake },
/* TPIDR_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b010),
NULL, reset_unknown, TPIDR_EL0 },
/* TPIDRRO_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
NULL, reset_unknown, TPIDRRO_EL0 },
/* DACR32_EL2 */
{ Op0(0b11), Op1(0b100), CRn(0b0011), CRm(0b0000), Op2(0b000),
NULL, reset_unknown, DACR32_EL2 },
/* IFSR32_EL2 */
{ Op0(0b11), Op1(0b100), CRn(0b0101), CRm(0b0000), Op2(0b001),
NULL, reset_unknown, IFSR32_EL2 },
/* FPEXC32_EL2 */
{ Op0(0b11), Op1(0b100), CRn(0b0101), CRm(0b0011), Op2(0b000),
NULL, reset_val, FPEXC32_EL2, 0x70 },
};
/*
* Trapped cp15 registers. TTBR0/TTBR1 get a double encoding,
* depending on the way they are accessed (as a 32bit or a 64bit
* register).
*/
static const struct sys_reg_desc cp15_regs[] = {
{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
{ Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_sctlr, NULL, c1_SCTLR },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 1), access_vm_reg, NULL, c2_TTBR1 },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 2), access_vm_reg, NULL, c2_TTBCR },
{ Op1( 0), CRn( 3), CRm( 0), Op2( 0), access_vm_reg, NULL, c3_DACR },
{ Op1( 0), CRn( 5), CRm( 0), Op2( 0), access_vm_reg, NULL, c5_DFSR },
{ Op1( 0), CRn( 5), CRm( 0), Op2( 1), access_vm_reg, NULL, c5_IFSR },
{ Op1( 0), CRn( 5), CRm( 1), Op2( 0), access_vm_reg, NULL, c5_ADFSR },
{ Op1( 0), CRn( 5), CRm( 1), Op2( 1), access_vm_reg, NULL, c5_AIFSR },
{ Op1( 0), CRn( 6), CRm( 0), Op2( 0), access_vm_reg, NULL, c6_DFAR },
{ Op1( 0), CRn( 6), CRm( 0), Op2( 2), access_vm_reg, NULL, c6_IFAR },
/*
* DC{C,I,CI}SW operations:
*/
{ Op1( 0), CRn( 7), CRm( 6), Op2( 2), access_dcsw },
{ Op1( 0), CRn( 7), CRm(10), Op2( 2), access_dcsw },
{ Op1( 0), CRn( 7), CRm(14), Op2( 2), access_dcsw },
{ Op1( 0), CRn( 9), CRm(12), Op2( 0), pm_fake },
{ Op1( 0), CRn( 9), CRm(12), Op2( 1), pm_fake },
{ Op1( 0), CRn( 9), CRm(12), Op2( 2), pm_fake },
{ Op1( 0), CRn( 9), CRm(12), Op2( 3), pm_fake },
{ Op1( 0), CRn( 9), CRm(12), Op2( 5), pm_fake },
{ Op1( 0), CRn( 9), CRm(12), Op2( 6), pm_fake },
{ Op1( 0), CRn( 9), CRm(12), Op2( 7), pm_fake },
{ Op1( 0), CRn( 9), CRm(13), Op2( 0), pm_fake },
{ Op1( 0), CRn( 9), CRm(13), Op2( 1), pm_fake },
{ Op1( 0), CRn( 9), CRm(13), Op2( 2), pm_fake },
{ Op1( 0), CRn( 9), CRm(14), Op2( 0), pm_fake },
{ Op1( 0), CRn( 9), CRm(14), Op2( 1), pm_fake },
{ Op1( 0), CRn( 9), CRm(14), Op2( 2), pm_fake },
{ Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, c10_PRRR },
{ Op1( 0), CRn(10), CRm( 2), Op2( 1), access_vm_reg, NULL, c10_NMRR },
{ Op1( 0), CRn(10), CRm( 3), Op2( 0), access_vm_reg, NULL, c10_AMAIR0 },
{ Op1( 0), CRn(10), CRm( 3), Op2( 1), access_vm_reg, NULL, c10_AMAIR1 },
{ Op1( 0), CRn(13), CRm( 0), Op2( 1), access_vm_reg, NULL, c13_CID },
{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, c2_TTBR1 },
};
/* Target specific emulation tables */
static struct kvm_sys_reg_target_table *target_tables[KVM_ARM_NUM_TARGETS];
void kvm_register_target_sys_reg_table(unsigned int target,
struct kvm_sys_reg_target_table *table)
{
target_tables[target] = table;
}
/* Get specific register table for this target. */
static const struct sys_reg_desc *get_target_table(unsigned target,
bool mode_is_64,
size_t *num)
{
struct kvm_sys_reg_target_table *table;
table = target_tables[target];
if (mode_is_64) {
*num = table->table64.num;
return table->table64.table;
} else {
*num = table->table32.num;
return table->table32.table;
}
}
static const struct sys_reg_desc *find_reg(const struct sys_reg_params *params,
const struct sys_reg_desc table[],
unsigned int num)
{
unsigned int i;
for (i = 0; i < num; i++) {
const struct sys_reg_desc *r = &table[i];
if (params->Op0 != r->Op0)
continue;
if (params->Op1 != r->Op1)
continue;
if (params->CRn != r->CRn)
continue;
if (params->CRm != r->CRm)
continue;
if (params->Op2 != r->Op2)
continue;
return r;
}
return NULL;
}
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 emulate_cp15(struct kvm_vcpu *vcpu,
const struct sys_reg_params *params)
{
size_t num;
const struct sys_reg_desc *table, *r;
table = get_target_table(vcpu->arch.target, false, &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)) {
/*
* Not having an accessor means that we have
* configured a trap that we don't know how to
* handle. This certainly qualifies as a gross bug
* that should be fixed right away.
*/
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));
return;
}
/* If access function fails, it should complain. */
}
kvm_err("Unsupported guest CP15 access at: %08lx\n", *vcpu_pc(vcpu));
print_sys_reg_instr(params);
kvm_inject_undefined(vcpu);
}
/**
* 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 sys_reg_params params;
u32 hsr = kvm_vcpu_get_hsr(vcpu);
int Rt2 = (hsr >> 10) & 0xf;
params.is_aarch32 = true;
params.is_32bit = false;
params.CRm = (hsr >> 1) & 0xf;
params.Rt = (hsr >> 5) & 0xf;
params.is_write = ((hsr & 1) == 0);
params.Op0 = 0;
params.Op1 = (hsr >> 16) & 0xf;
params.Op2 = 0;
params.CRn = 0;
/*
* Massive hack here. Store Rt2 in the top 32bits so we only
* have one register to deal with. As we use the same trap
* backends between AArch32 and AArch64, we get away with it.
*/
if (params.is_write) {
u64 val = *vcpu_reg(vcpu, params.Rt);
val &= 0xffffffff;
val |= *vcpu_reg(vcpu, Rt2) << 32;
*vcpu_reg(vcpu, params.Rt) = val;
}
emulate_cp15(vcpu, &params);
/* Do the opposite hack for the read side */
if (!params.is_write) {
u64 val = *vcpu_reg(vcpu, params.Rt);
val >>= 32;
*vcpu_reg(vcpu, Rt2) = val;
}
return 1;
}
/**
* 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 sys_reg_params params;
u32 hsr = kvm_vcpu_get_hsr(vcpu);
params.is_aarch32 = true;
params.is_32bit = true;
params.CRm = (hsr >> 1) & 0xf;
params.Rt = (hsr >> 5) & 0xf;
params.is_write = ((hsr & 1) == 0);
params.CRn = (hsr >> 10) & 0xf;
params.Op0 = 0;
params.Op1 = (hsr >> 14) & 0x7;
params.Op2 = (hsr >> 17) & 0x7;
emulate_cp15(vcpu, &params);
return 1;
}
static int emulate_sys_reg(struct kvm_vcpu *vcpu,
const struct sys_reg_params *params)
{
size_t num;
const struct sys_reg_desc *table, *r;
table = get_target_table(vcpu->arch.target, true, &num);
/* Search target-specific then generic table. */
r = find_reg(params, table, num);
if (!r)
r = find_reg(params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
if (likely(r)) {
/*
* Not having an accessor means that we have
* configured a trap that we don't know how to
* handle. This certainly qualifies as a gross bug
* that should be fixed right away.
*/
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));
return 1;
}
/* If access function fails, it should complain. */
} else {
kvm_err("Unsupported guest sys_reg access at: %lx\n",
*vcpu_pc(vcpu));
print_sys_reg_instr(params);
}
kvm_inject_undefined(vcpu);
return 1;
}
static void reset_sys_reg_descs(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *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_sys_reg -- handles a mrs/msr trap on a guest sys_reg access
* @vcpu: The VCPU pointer
* @run: The kvm_run struct
*/
int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
struct sys_reg_params params;
unsigned long esr = kvm_vcpu_get_hsr(vcpu);
params.is_aarch32 = false;
params.is_32bit = false;
params.Op0 = (esr >> 20) & 3;
params.Op1 = (esr >> 14) & 0x7;
params.CRn = (esr >> 10) & 0xf;
params.CRm = (esr >> 1) & 0xf;
params.Op2 = (esr >> 17) & 0x7;
params.Rt = (esr >> 5) & 0x1f;
params.is_write = !(esr & 1);
return emulate_sys_reg(vcpu, &params);
}
/******************************************************************************
* Userspace API
*****************************************************************************/
static bool index_to_params(u64 id, struct sys_reg_params *params)
{
switch (id & KVM_REG_SIZE_MASK) {
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_ARM64_SYSREG_OP0_MASK
| KVM_REG_ARM64_SYSREG_OP1_MASK
| KVM_REG_ARM64_SYSREG_CRN_MASK
| KVM_REG_ARM64_SYSREG_CRM_MASK
| KVM_REG_ARM64_SYSREG_OP2_MASK))
return false;
params->Op0 = ((id & KVM_REG_ARM64_SYSREG_OP0_MASK)
>> KVM_REG_ARM64_SYSREG_OP0_SHIFT);
params->Op1 = ((id & KVM_REG_ARM64_SYSREG_OP1_MASK)
>> KVM_REG_ARM64_SYSREG_OP1_SHIFT);
params->CRn = ((id & KVM_REG_ARM64_SYSREG_CRN_MASK)
>> KVM_REG_ARM64_SYSREG_CRN_SHIFT);
params->CRm = ((id & KVM_REG_ARM64_SYSREG_CRM_MASK)
>> KVM_REG_ARM64_SYSREG_CRM_SHIFT);
params->Op2 = ((id & KVM_REG_ARM64_SYSREG_OP2_MASK)
>> KVM_REG_ARM64_SYSREG_OP2_SHIFT);
return true;
default:
return false;
}
}
/* Decode an index value, and find the sys_reg_desc entry. */
static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
u64 id)
{
size_t num;
const struct sys_reg_desc *table, *r;
struct sys_reg_params params;
/* We only do sys_reg for now. */
if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
return NULL;
if (!index_to_params(id, &params))
return NULL;
table = get_target_table(vcpu->arch.target, true, &num);
r = find_reg(&params, table, num);
if (!r)
r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
/* Not saved in the sys_reg array? */
if (r && !r->reg)
r = NULL;
return r;
}
/*
* These are the invariant sys_reg 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.
*/
#define FUNCTION_INVARIANT(reg) \
static void get_##reg(struct kvm_vcpu *v, \
const struct sys_reg_desc *r) \
{ \
u64 val; \
\
asm volatile("mrs %0, " __stringify(reg) "\n" \
: "=r" (val)); \
((struct sys_reg_desc *)r)->val = val; \
}
FUNCTION_INVARIANT(midr_el1)
FUNCTION_INVARIANT(ctr_el0)
FUNCTION_INVARIANT(revidr_el1)
FUNCTION_INVARIANT(id_pfr0_el1)
FUNCTION_INVARIANT(id_pfr1_el1)
FUNCTION_INVARIANT(id_dfr0_el1)
FUNCTION_INVARIANT(id_afr0_el1)
FUNCTION_INVARIANT(id_mmfr0_el1)
FUNCTION_INVARIANT(id_mmfr1_el1)
FUNCTION_INVARIANT(id_mmfr2_el1)
FUNCTION_INVARIANT(id_mmfr3_el1)
FUNCTION_INVARIANT(id_isar0_el1)
FUNCTION_INVARIANT(id_isar1_el1)
FUNCTION_INVARIANT(id_isar2_el1)
FUNCTION_INVARIANT(id_isar3_el1)
FUNCTION_INVARIANT(id_isar4_el1)
FUNCTION_INVARIANT(id_isar5_el1)
FUNCTION_INVARIANT(clidr_el1)
FUNCTION_INVARIANT(aidr_el1)
/* ->val is filled in by kvm_sys_reg_table_init() */
static struct sys_reg_desc invariant_sys_regs[] = {
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b000),
NULL, get_midr_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0000), Op2(0b110),
NULL, get_revidr_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b000),
NULL, get_id_pfr0_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b001),
NULL, get_id_pfr1_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b010),
NULL, get_id_dfr0_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b011),
NULL, get_id_afr0_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b100),
NULL, get_id_mmfr0_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b101),
NULL, get_id_mmfr1_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b110),
NULL, get_id_mmfr2_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0001), Op2(0b111),
NULL, get_id_mmfr3_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b000),
NULL, get_id_isar0_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b001),
NULL, get_id_isar1_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b010),
NULL, get_id_isar2_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b011),
NULL, get_id_isar3_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b100),
NULL, get_id_isar4_el1 },
{ Op0(0b11), Op1(0b000), CRn(0b0000), CRm(0b0010), Op2(0b101),
NULL, get_id_isar5_el1 },
{ Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b001),
NULL, get_clidr_el1 },
{ Op0(0b11), Op1(0b001), CRn(0b0000), CRm(0b0000), Op2(0b111),
NULL, get_aidr_el1 },
{ Op0(0b11), Op1(0b011), CRn(0b0000), CRm(0b0000), Op2(0b001),
NULL, get_ctr_el0 },
};
static int reg_from_user(void *val, const void __user *uaddr, u64 id)
{
/* This Just Works because we are little endian. */
if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
return -EFAULT;
return 0;
}
static int reg_to_user(void __user *uaddr, const void *val, u64 id)
{
/* This Just Works because we are little endian. */
if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
return -EFAULT;
return 0;
}
static int get_invariant_sys_reg(u64 id, void __user *uaddr)
{
struct sys_reg_params params;
const struct sys_reg_desc *r;
if (!index_to_params(id, &params))
return -ENOENT;
r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
if (!r)
return -ENOENT;
return reg_to_user(uaddr, &r->val, id);
}
static int set_invariant_sys_reg(u64 id, void __user *uaddr)
{
struct sys_reg_params params;
const struct sys_reg_desc *r;
int err;
u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
if (!index_to_params(id, &params))
return -ENOENT;
r = find_reg(&params, invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs));
if (!r)
return -ENOENT;
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 -ENOENT;
/* 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;
}
}
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;
}
}
int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct sys_reg_desc *r;
void __user *uaddr = (void __user *)(unsigned long)reg->addr;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_get(reg->id, uaddr);
if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
return -ENOENT;
r = index_to_sys_reg_desc(vcpu, reg->id);
if (!r)
return get_invariant_sys_reg(reg->id, uaddr);
return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
}
int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct sys_reg_desc *r;
void __user *uaddr = (void __user *)(unsigned long)reg->addr;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_set(reg->id, uaddr);
if (KVM_REG_SIZE(reg->id) != sizeof(__u64))
return -ENOENT;
r = index_to_sys_reg_desc(vcpu, reg->id);
if (!r)
return set_invariant_sys_reg(reg->id, uaddr);
return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
}
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 sys_reg_to_index(const struct sys_reg_desc *reg)
{
return (KVM_REG_ARM64 | KVM_REG_SIZE_U64 |
KVM_REG_ARM64_SYSREG |
(reg->Op0 << KVM_REG_ARM64_SYSREG_OP0_SHIFT) |
(reg->Op1 << KVM_REG_ARM64_SYSREG_OP1_SHIFT) |
(reg->CRn << KVM_REG_ARM64_SYSREG_CRN_SHIFT) |
(reg->CRm << KVM_REG_ARM64_SYSREG_CRM_SHIFT) |
(reg->Op2 << KVM_REG_ARM64_SYSREG_OP2_SHIFT));
}
static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind)
{
if (!*uind)
return true;
if (put_user(sys_reg_to_index(reg), *uind))
return false;
(*uind)++;
return true;
}
/* Assumed ordered tables, see kvm_sys_reg_table_init. */
static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
{
const struct sys_reg_desc *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, true, &num);
end1 = i1 + num;
i2 = sys_reg_descs;
end2 = sys_reg_descs + ARRAY_SIZE(sys_reg_descs);
BUG_ON(i1 == end1 || i2 == end2);
/* Walk carefully, as both tables may refer to the same register. */
while (i1 || i2) {
int cmp = cmp_sys_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_sys_reg_descs(struct kvm_vcpu *vcpu)
{
return ARRAY_SIZE(invariant_sys_regs)
+ num_demux_regs()
+ walk_sys_regs(vcpu, (u64 __user *)NULL);
}
int kvm_arm_copy_sys_reg_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_sys_regs); i++) {
if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
return -EFAULT;
uindices++;
}
err = walk_sys_regs(vcpu, uindices);
if (err < 0)
return err;
uindices += err;
return write_demux_regids(uindices);
}
void kvm_sys_reg_table_init(void)
{
unsigned int i;
struct sys_reg_desc clidr;
/* Make sure tables are unique and in order. */
for (i = 1; i < ARRAY_SIZE(sys_reg_descs); i++)
BUG_ON(cmp_sys_reg(&sys_reg_descs[i-1], &sys_reg_descs[i]) >= 0);
/* We abuse the reset function to overwrite the table itself. */
for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++)
invariant_sys_regs[i].reset(NULL, &invariant_sys_regs[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.
*/
get_clidr_el1(NULL, &clidr); /* Ugly... */
cache_levels = clidr.val;
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_sys_regs - sets system 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_sys_regs(struct kvm_vcpu *vcpu)
{
size_t num;
const struct sys_reg_desc *table;
/* Catch someone adding a register without putting in reset entry. */
memset(&vcpu->arch.ctxt.sys_regs, 0x42, sizeof(vcpu->arch.ctxt.sys_regs));
/* Generic chip reset first (so target could override). */
reset_sys_reg_descs(vcpu, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
table = get_target_table(vcpu->arch.target, true, &num);
reset_sys_reg_descs(vcpu, table, num);
for (num = 1; num < NR_SYS_REGS; num++)
if (vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
panic("Didn't reset vcpu_sys_reg(%zi)", num);
}
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