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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020-2023 Loongson Technology Corporation Limited
*/
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/preempt.h>
#include <linux/vmalloc.h>
#include <asm/fpu.h>
#include <asm/inst.h>
#include <asm/loongarch.h>
#include <asm/mmzone.h>
#include <asm/numa.h>
#include <asm/time.h>
#include <asm/tlb.h>
#include <asm/kvm_csr.h>
#include <asm/kvm_vcpu.h>
#include "trace.h"
static unsigned long kvm_emu_read_csr(struct kvm_vcpu *vcpu, int csrid)
{
unsigned long val = 0;
struct loongarch_csrs *csr = vcpu->arch.csr;
/*
* From LoongArch Reference Manual Volume 1 Chapter 4.2.1
* For undefined CSR id, return value is 0
*/
if (get_gcsr_flag(csrid) & SW_GCSR)
val = kvm_read_sw_gcsr(csr, csrid);
else
pr_warn_once("Unsupported csrrd 0x%x with pc %lx\n", csrid, vcpu->arch.pc);
return val;
}
static unsigned long kvm_emu_write_csr(struct kvm_vcpu *vcpu, int csrid, unsigned long val)
{
unsigned long old = 0;
struct loongarch_csrs *csr = vcpu->arch.csr;
if (get_gcsr_flag(csrid) & SW_GCSR) {
old = kvm_read_sw_gcsr(csr, csrid);
kvm_write_sw_gcsr(csr, csrid, val);
} else
pr_warn_once("Unsupported csrwr 0x%x with pc %lx\n", csrid, vcpu->arch.pc);
return old;
}
static unsigned long kvm_emu_xchg_csr(struct kvm_vcpu *vcpu, int csrid,
unsigned long csr_mask, unsigned long val)
{
unsigned long old = 0;
struct loongarch_csrs *csr = vcpu->arch.csr;
if (get_gcsr_flag(csrid) & SW_GCSR) {
old = kvm_read_sw_gcsr(csr, csrid);
val = (old & ~csr_mask) | (val & csr_mask);
kvm_write_sw_gcsr(csr, csrid, val);
old = old & csr_mask;
} else
pr_warn_once("Unsupported csrxchg 0x%x with pc %lx\n", csrid, vcpu->arch.pc);
return old;
}
static int kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst)
{
unsigned int rd, rj, csrid;
unsigned long csr_mask, val = 0;
/*
* CSR value mask imm
* rj = 0 means csrrd
* rj = 1 means csrwr
* rj != 0,1 means csrxchg
*/
rd = inst.reg2csr_format.rd;
rj = inst.reg2csr_format.rj;
csrid = inst.reg2csr_format.csr;
/* Process CSR ops */
switch (rj) {
case 0: /* process csrrd */
val = kvm_emu_read_csr(vcpu, csrid);
vcpu->arch.gprs[rd] = val;
break;
case 1: /* process csrwr */
val = vcpu->arch.gprs[rd];
val = kvm_emu_write_csr(vcpu, csrid, val);
vcpu->arch.gprs[rd] = val;
break;
default: /* process csrxchg */
val = vcpu->arch.gprs[rd];
csr_mask = vcpu->arch.gprs[rj];
val = kvm_emu_xchg_csr(vcpu, csrid, csr_mask, val);
vcpu->arch.gprs[rd] = val;
}
return EMULATE_DONE;
}
int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu)
{
int ret;
unsigned long val;
u32 addr, rd, rj, opcode;
/*
* Each IOCSR with different opcode
*/
rd = inst.reg2_format.rd;
rj = inst.reg2_format.rj;
opcode = inst.reg2_format.opcode;
addr = vcpu->arch.gprs[rj];
ret = EMULATE_DO_IOCSR;
run->iocsr_io.phys_addr = addr;
run->iocsr_io.is_write = 0;
/* LoongArch is Little endian */
switch (opcode) {
case iocsrrdb_op:
run->iocsr_io.len = 1;
break;
case iocsrrdh_op:
run->iocsr_io.len = 2;
break;
case iocsrrdw_op:
run->iocsr_io.len = 4;
break;
case iocsrrdd_op:
run->iocsr_io.len = 8;
break;
case iocsrwrb_op:
run->iocsr_io.len = 1;
run->iocsr_io.is_write = 1;
break;
case iocsrwrh_op:
run->iocsr_io.len = 2;
run->iocsr_io.is_write = 1;
break;
case iocsrwrw_op:
run->iocsr_io.len = 4;
run->iocsr_io.is_write = 1;
break;
case iocsrwrd_op:
run->iocsr_io.len = 8;
run->iocsr_io.is_write = 1;
break;
default:
ret = EMULATE_FAIL;
break;
}
if (ret == EMULATE_DO_IOCSR) {
if (run->iocsr_io.is_write) {
val = vcpu->arch.gprs[rd];
memcpy(run->iocsr_io.data, &val, run->iocsr_io.len);
}
vcpu->arch.io_gpr = rd;
}
return ret;
}
int kvm_complete_iocsr_read(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
enum emulation_result er = EMULATE_DONE;
unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
switch (run->iocsr_io.len) {
case 1:
*gpr = *(s8 *)run->iocsr_io.data;
break;
case 2:
*gpr = *(s16 *)run->iocsr_io.data;
break;
case 4:
*gpr = *(s32 *)run->iocsr_io.data;
break;
case 8:
*gpr = *(s64 *)run->iocsr_io.data;
break;
default:
kvm_err("Bad IOCSR length: %d, addr is 0x%lx\n",
run->iocsr_io.len, vcpu->arch.badv);
er = EMULATE_FAIL;
break;
}
return er;
}
int kvm_emu_idle(struct kvm_vcpu *vcpu)
{
++vcpu->stat.idle_exits;
trace_kvm_exit_idle(vcpu, KVM_TRACE_EXIT_IDLE);
if (!kvm_arch_vcpu_runnable(vcpu)) {
/*
* Switch to the software timer before halt-polling/blocking as
* the guest's timer may be a break event for the vCPU, and the
* hypervisor timer runs only when the CPU is in guest mode.
* Switch before halt-polling so that KVM recognizes an expired
* timer before blocking.
*/
kvm_save_timer(vcpu);
kvm_vcpu_block(vcpu);
}
return EMULATE_DONE;
}
static int kvm_trap_handle_gspr(struct kvm_vcpu *vcpu)
{
int rd, rj;
unsigned int index;
unsigned long curr_pc;
larch_inst inst;
enum emulation_result er = EMULATE_DONE;
struct kvm_run *run = vcpu->run;
/* Fetch the instruction */
inst.word = vcpu->arch.badi;
curr_pc = vcpu->arch.pc;
update_pc(&vcpu->arch);
trace_kvm_exit_gspr(vcpu, inst.word);
er = EMULATE_FAIL;
switch (((inst.word >> 24) & 0xff)) {
case 0x0: /* CPUCFG GSPR */
if (inst.reg2_format.opcode == 0x1B) {
rd = inst.reg2_format.rd;
rj = inst.reg2_format.rj;
++vcpu->stat.cpucfg_exits;
index = vcpu->arch.gprs[rj];
er = EMULATE_DONE;
/*
* By LoongArch Reference Manual 2.2.10.5
* return value is 0 for undefined cpucfg index
*/
if (index < KVM_MAX_CPUCFG_REGS)
vcpu->arch.gprs[rd] = vcpu->arch.cpucfg[index];
else
vcpu->arch.gprs[rd] = 0;
}
break;
case 0x4: /* CSR{RD,WR,XCHG} GSPR */
er = kvm_handle_csr(vcpu, inst);
break;
case 0x6: /* Cache, Idle and IOCSR GSPR */
switch (((inst.word >> 22) & 0x3ff)) {
case 0x18: /* Cache GSPR */
er = EMULATE_DONE;
trace_kvm_exit_cache(vcpu, KVM_TRACE_EXIT_CACHE);
break;
case 0x19: /* Idle/IOCSR GSPR */
switch (((inst.word >> 15) & 0x1ffff)) {
case 0xc90: /* IOCSR GSPR */
er = kvm_emu_iocsr(inst, run, vcpu);
break;
case 0xc91: /* Idle GSPR */
er = kvm_emu_idle(vcpu);
break;
default:
er = EMULATE_FAIL;
break;
}
break;
default:
er = EMULATE_FAIL;
break;
}
break;
default:
er = EMULATE_FAIL;
break;
}
/* Rollback PC only if emulation was unsuccessful */
if (er == EMULATE_FAIL) {
kvm_err("[%#lx]%s: unsupported gspr instruction 0x%08x\n",
curr_pc, __func__, inst.word);
kvm_arch_vcpu_dump_regs(vcpu);
vcpu->arch.pc = curr_pc;
}
return er;
}
/*
* Trigger GSPR:
* 1) Execute CPUCFG instruction;
* 2) Execute CACOP/IDLE instructions;
* 3) Access to unimplemented CSRs/IOCSRs.
*/
static int kvm_handle_gspr(struct kvm_vcpu *vcpu)
{
int ret = RESUME_GUEST;
enum emulation_result er = EMULATE_DONE;
er = kvm_trap_handle_gspr(vcpu);
if (er == EMULATE_DONE) {
ret = RESUME_GUEST;
} else if (er == EMULATE_DO_MMIO) {
vcpu->run->exit_reason = KVM_EXIT_MMIO;
ret = RESUME_HOST;
} else if (er == EMULATE_DO_IOCSR) {
vcpu->run->exit_reason = KVM_EXIT_LOONGARCH_IOCSR;
ret = RESUME_HOST;
} else {
kvm_queue_exception(vcpu, EXCCODE_INE, 0);
ret = RESUME_GUEST;
}
return ret;
}
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