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LoongArch: KVM: Implement handle csr exception

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Implement kvm handle LoongArch vcpu exit caused by reading, writing and
exchanging csr. Use kvm_vcpu_arch::csr structure to emulate the software
registers.

Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Tested-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Tianrui Zhao 2023-10-02 10:01:28 +08:00 committed by Huacai Chen
parent 752e2cd7b4
commit da50f5a693
1 changed files with 105 additions and 0 deletions
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105
arch/loongarch/kvm/exit.c Normal file
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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;
}