Commit da50f5a6 authored by Tianrui Zhao's avatar Tianrui Zhao Committed by Huacai Chen
Browse files

LoongArch: KVM: Implement handle csr exception 



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: default avatarBibo Mao <maobibo@loongson.cn>
Tested-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarTianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 752e2cd7

arch/loongarch/kvm/exit.c

0 → 100644
+105 −0
Original line number Diff line number Diff line 
// 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;

}