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f82393426afb7c82f7618b3b4e440d8dd2b40c08
android_kernel_xiaomi_sm8450/arch/mips/kvm/kvm_trap_emul.c
James Hogan f82393426a MIPS: KVM: Add master disable count interface 
Expose two new virtual registers to userland via the
KVM_{GET,SET}_ONE_REG ioctls.

KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just
contains a master disable count bit. This can be used by userland to
freeze the timer in order to read a consistent state from the timer
count value and timer interrupt pending bit. This cannot be done with
the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is
also in CP0_Cause so it would be impossible to stop the timer without
also risking a race with an hrtimer interrupt and having to explicitly
check whether an interrupt should have occurred.

When the timer is re-enabled it resumes without losing time, i.e. the
CP0_Count value jumps to what it would have been had the timer not been
disabled, which would also be impossible to do from userland with
CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer
interrupt would have occurred had the timer not been disabled it is
queued when the timer is re-enabled.

This works by storing the nanosecond monotonic time when the master
disable is set, and using it for various operations instead of the
current monotonic time (e.g. when recalculating the bias when the
CP0_Count is set), until the master disable is cleared again, i.e. the
timer state is read/written as it would have been at that time. This
state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME
virtual register so that userland can determine the exact time the
master disable took effect.

This should allow userland to atomically save the state of the timer,
and later restore it.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: kvm@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: David Daney <david.daney@cavium.com>
Cc: Sanjay Lal <sanjayl@kymasys.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-30 13:02:45 +02:00

501 lines
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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* KVM/MIPS: Deliver/Emulate exceptions to the guest kernel
*
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
* Authors: Sanjay Lal <sanjayl@kymasys.com>
*/
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/kvm_host.h>
#include "kvm_mips_opcode.h"
#include "kvm_mips_int.h"
static gpa_t kvm_trap_emul_gva_to_gpa_cb(gva_t gva)
{
gpa_t gpa;
uint32_t kseg = KSEGX(gva);
if ((kseg == CKSEG0) || (kseg == CKSEG1))
gpa = CPHYSADDR(gva);
else {
printk("%s: cannot find GPA for GVA: %#lx\n", __func__, gva);
kvm_mips_dump_host_tlbs();
gpa = KVM_INVALID_ADDR;
}
#ifdef DEBUG
kvm_debug("%s: gva %#lx, gpa: %#llx\n", __func__, gva, gpa);
#endif
return gpa;
}
static int kvm_trap_emul_handle_cop_unusable(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 1) {
er = kvm_mips_emulate_fpu_exc(cause, opc, run, vcpu);
} else
er = kvm_mips_emulate_inst(cause, opc, run, vcpu);
switch (er) {
case EMULATE_DONE:
ret = RESUME_GUEST;
break;
case EMULATE_FAIL:
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
break;
case EMULATE_WAIT:
run->exit_reason = KVM_EXIT_INTR;
ret = RESUME_HOST;
break;
default:
BUG();
}
return ret;
}
static int kvm_trap_emul_handle_tlb_mod(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
if (KVM_GUEST_KSEGX(badvaddr) < KVM_GUEST_KSEG0
|| KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG23) {
#ifdef DEBUG
kvm_debug
("USER/KSEG23 ADDR TLB MOD fault: cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
#endif
er = kvm_mips_handle_tlbmod(cause, opc, run, vcpu);
if (er == EMULATE_DONE)
ret = RESUME_GUEST;
else {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else if (KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG0) {
/* XXXKYMA: The guest kernel does not expect to get this fault when we are not
* using HIGHMEM. Need to address this in a HIGHMEM kernel
*/
printk
("TLB MOD fault not handled, cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
kvm_mips_dump_host_tlbs();
kvm_arch_vcpu_dump_regs(vcpu);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
} else {
printk
("Illegal TLB Mod fault address , cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
kvm_mips_dump_host_tlbs();
kvm_arch_vcpu_dump_regs(vcpu);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_handle_tlb_st_miss(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
if (((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR)
&& KVM_GUEST_KERNEL_MODE(vcpu)) {
if (kvm_mips_handle_commpage_tlb_fault(badvaddr, vcpu) < 0) {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else if (KVM_GUEST_KSEGX(badvaddr) < KVM_GUEST_KSEG0
|| KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG23) {
#ifdef DEBUG
kvm_debug
("USER ADDR TLB LD fault: cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
#endif
er = kvm_mips_handle_tlbmiss(cause, opc, run, vcpu);
if (er == EMULATE_DONE)
ret = RESUME_GUEST;
else {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else if (KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG0) {
/* All KSEG0 faults are handled by KVM, as the guest kernel does not
* expect to ever get them
*/
if (kvm_mips_handle_kseg0_tlb_fault
(vcpu->arch.host_cp0_badvaddr, vcpu) < 0) {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else {
kvm_err
("Illegal TLB LD fault address , cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
kvm_mips_dump_host_tlbs();
kvm_arch_vcpu_dump_regs(vcpu);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_handle_tlb_ld_miss(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
if (((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR)
&& KVM_GUEST_KERNEL_MODE(vcpu)) {
if (kvm_mips_handle_commpage_tlb_fault(badvaddr, vcpu) < 0) {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else if (KVM_GUEST_KSEGX(badvaddr) < KVM_GUEST_KSEG0
|| KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG23) {
#ifdef DEBUG
kvm_debug("USER ADDR TLB ST fault: PC: %#lx, BadVaddr: %#lx\n",
vcpu->arch.pc, badvaddr);
#endif
/* User Address (UA) fault, this could happen if
* (1) TLB entry not present/valid in both Guest and shadow host TLBs, in this
* case we pass on the fault to the guest kernel and let it handle it.
* (2) TLB entry is present in the Guest TLB but not in the shadow, in this
* case we inject the TLB from the Guest TLB into the shadow host TLB
*/
er = kvm_mips_handle_tlbmiss(cause, opc, run, vcpu);
if (er == EMULATE_DONE)
ret = RESUME_GUEST;
else {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else if (KVM_GUEST_KSEGX(badvaddr) == KVM_GUEST_KSEG0) {
if (kvm_mips_handle_kseg0_tlb_fault
(vcpu->arch.host_cp0_badvaddr, vcpu) < 0) {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
} else {
printk
("Illegal TLB ST fault address , cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
kvm_mips_dump_host_tlbs();
kvm_arch_vcpu_dump_regs(vcpu);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_handle_addr_err_st(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
if (KVM_GUEST_KERNEL_MODE(vcpu)
&& (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1)) {
#ifdef DEBUG
kvm_debug("Emulate Store to MMIO space\n");
#endif
er = kvm_mips_emulate_inst(cause, opc, run, vcpu);
if (er == EMULATE_FAIL) {
printk("Emulate Store to MMIO space failed\n");
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
} else {
run->exit_reason = KVM_EXIT_MMIO;
ret = RESUME_HOST;
}
} else {
printk
("Address Error (STORE): cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_handle_addr_err_ld(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
if (KSEGX(badvaddr) == CKSEG0 || KSEGX(badvaddr) == CKSEG1) {
#ifdef DEBUG
kvm_debug("Emulate Load from MMIO space @ %#lx\n", badvaddr);
#endif
er = kvm_mips_emulate_inst(cause, opc, run, vcpu);
if (er == EMULATE_FAIL) {
printk("Emulate Load from MMIO space failed\n");
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
} else {
run->exit_reason = KVM_EXIT_MMIO;
ret = RESUME_HOST;
}
} else {
printk
("Address Error (LOAD): cause %#lx, PC: %p, BadVaddr: %#lx\n",
cause, opc, badvaddr);
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
er = EMULATE_FAIL;
}
return ret;
}
static int kvm_trap_emul_handle_syscall(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
er = kvm_mips_emulate_syscall(cause, opc, run, vcpu);
if (er == EMULATE_DONE)
ret = RESUME_GUEST;
else {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_handle_res_inst(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
er = kvm_mips_handle_ri(cause, opc, run, vcpu);
if (er == EMULATE_DONE)
ret = RESUME_GUEST;
else {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_handle_break(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
unsigned long cause = vcpu->arch.host_cp0_cause;
enum emulation_result er = EMULATE_DONE;
int ret = RESUME_GUEST;
er = kvm_mips_emulate_bp_exc(cause, opc, run, vcpu);
if (er == EMULATE_DONE)
ret = RESUME_GUEST;
else {
run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
ret = RESUME_HOST;
}
return ret;
}
static int kvm_trap_emul_vm_init(struct kvm *kvm)
{
return 0;
}
static int kvm_trap_emul_vcpu_init(struct kvm_vcpu *vcpu)
{
return 0;
}
static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
uint32_t config1;
int vcpu_id = vcpu->vcpu_id;
/* Arch specific stuff, set up config registers properly so that the
* guest will come up as expected, for now we simulate a
* MIPS 24kc
*/
kvm_write_c0_guest_prid(cop0, 0x00019300);
kvm_write_c0_guest_config(cop0,
MIPS_CONFIG0 | (0x1 << CP0C0_AR) |
(MMU_TYPE_R4000 << CP0C0_MT));
/* Read the cache characteristics from the host Config1 Register */
config1 = (read_c0_config1() & ~0x7f);
/* Set up MMU size */
config1 &= ~(0x3f << 25);
config1 |= ((KVM_MIPS_GUEST_TLB_SIZE - 1) << 25);
/* We unset some bits that we aren't emulating */
config1 &=
~((1 << CP0C1_C2) | (1 << CP0C1_MD) | (1 << CP0C1_PC) |
(1 << CP0C1_WR) | (1 << CP0C1_CA));
kvm_write_c0_guest_config1(cop0, config1);
kvm_write_c0_guest_config2(cop0, MIPS_CONFIG2);
/* MIPS_CONFIG2 | (read_c0_config2() & 0xfff) */
kvm_write_c0_guest_config3(cop0,
MIPS_CONFIG3 | (0 << CP0C3_VInt) | (1 <<
CP0C3_ULRI));
/* Set Wait IE/IXMT Ignore in Config7, IAR, AR */
kvm_write_c0_guest_config7(cop0, (MIPS_CONF7_WII) | (1 << 10));
/* Setup IntCtl defaults, compatibilty mode for timer interrupts (HW5) */
kvm_write_c0_guest_intctl(cop0, 0xFC000000);
/* Put in vcpu id as CPUNum into Ebase Reg to handle SMP Guests */
kvm_write_c0_guest_ebase(cop0, KVM_GUEST_KSEG0 | (vcpu_id & 0xFF));
return 0;
}
static int kvm_trap_emul_get_one_reg(struct kvm_vcpu *vcpu,
const struct kvm_one_reg *reg,
s64 *v)
{
switch (reg->id) {
case KVM_REG_MIPS_CP0_COUNT:
*v = kvm_mips_read_count(vcpu);
break;
case KVM_REG_MIPS_COUNT_CTL:
*v = vcpu->arch.count_ctl;
break;
case KVM_REG_MIPS_COUNT_RESUME:
*v = ktime_to_ns(vcpu->arch.count_resume);
break;
default:
return -EINVAL;
}
return 0;
}
static int kvm_trap_emul_set_one_reg(struct kvm_vcpu *vcpu,
const struct kvm_one_reg *reg,
s64 v)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
int ret = 0;
switch (reg->id) {
case KVM_REG_MIPS_CP0_COUNT:
kvm_mips_write_count(vcpu, v);
break;
case KVM_REG_MIPS_CP0_COMPARE:
kvm_mips_write_compare(vcpu, v);
break;
case KVM_REG_MIPS_CP0_CAUSE:
/*
* If the timer is stopped or started (DC bit) it must look
* atomic with changes to the interrupt pending bits (TI, IRQ5).
* A timer interrupt should not happen in between.
*/
if ((kvm_read_c0_guest_cause(cop0) ^ v) & CAUSEF_DC) {
if (v & CAUSEF_DC) {
/* disable timer first */
kvm_mips_count_disable_cause(vcpu);
kvm_change_c0_guest_cause(cop0, ~CAUSEF_DC, v);
} else {
/* enable timer last */
kvm_change_c0_guest_cause(cop0, ~CAUSEF_DC, v);
kvm_mips_count_enable_cause(vcpu);
}
} else {
kvm_write_c0_guest_cause(cop0, v);
}
break;
case KVM_REG_MIPS_COUNT_CTL:
ret = kvm_mips_set_count_ctl(vcpu, v);
break;
case KVM_REG_MIPS_COUNT_RESUME:
ret = kvm_mips_set_count_resume(vcpu, v);
break;
default:
return -EINVAL;
}
return ret;
}
static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
/* exit handlers */
.handle_cop_unusable = kvm_trap_emul_handle_cop_unusable,
.handle_tlb_mod = kvm_trap_emul_handle_tlb_mod,
.handle_tlb_st_miss = kvm_trap_emul_handle_tlb_st_miss,
.handle_tlb_ld_miss = kvm_trap_emul_handle_tlb_ld_miss,
.handle_addr_err_st = kvm_trap_emul_handle_addr_err_st,
.handle_addr_err_ld = kvm_trap_emul_handle_addr_err_ld,
.handle_syscall = kvm_trap_emul_handle_syscall,
.handle_res_inst = kvm_trap_emul_handle_res_inst,
.handle_break = kvm_trap_emul_handle_break,
.vm_init = kvm_trap_emul_vm_init,
.vcpu_init = kvm_trap_emul_vcpu_init,
.vcpu_setup = kvm_trap_emul_vcpu_setup,
.gva_to_gpa = kvm_trap_emul_gva_to_gpa_cb,
.queue_timer_int = kvm_mips_queue_timer_int_cb,
.dequeue_timer_int = kvm_mips_dequeue_timer_int_cb,
.queue_io_int = kvm_mips_queue_io_int_cb,
.dequeue_io_int = kvm_mips_dequeue_io_int_cb,
.irq_deliver = kvm_mips_irq_deliver_cb,
.irq_clear = kvm_mips_irq_clear_cb,
.get_one_reg = kvm_trap_emul_get_one_reg,
.set_one_reg = kvm_trap_emul_set_one_reg,
};
int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks)
{
*install_callbacks = &kvm_trap_emul_callbacks;
return 0;
}
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