Commit a9f6765d authored by Bibo Mao's avatar Bibo Mao Committed by Xianglai Li
Browse files

LoongArch: KVM: Add cpucfg area for kvm hypervisor 

mainline inclusion
from mainline-v6.10-rc1
commit 9753d3037964fffa5c57de8c57168dc1a4832dd4
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IAZJDO


CVE: NA

--------------------------------

Instruction cpucfg can be used to get processor features. And there
is a trap exception when it is executed in VM mode, and also it can be
used to provide cpu features to VM. On real hardware cpucfg area 0 - 20
is used by now. Here one specified area 0x40000000 -- 0x400000ff is used
for KVM hypervisor to provide PV features, and the area can be extended
for other hypervisors in future. This area will never be used for real
HW, it is only used by software.

Signed-off-by: default avatarBibo Mao <maobibo@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
Signed-off-by: default avatarXianglai Li <lixianglai@loongson.cn>
parent 914e5adc

arch/loongarch/kvm/exit.c

+42 −48
Original line number Diff line number Diff line
@@ -21,6 +21,47 @@ 
#include <asm/kvm_vcpu.h>

#include "trace.h"



static int kvm_emu_cpucfg(struct kvm_vcpu *vcpu, larch_inst inst)

{

	int rd, rj;

	unsigned int index, ret;



	if (inst.reg2_format.opcode != cpucfg_op)

		return EMULATE_FAIL;



	rd = inst.reg2_format.rd;

	rj = inst.reg2_format.rj;

	++vcpu->stat.cpucfg_exits;

	index = vcpu->arch.gprs[rj];



	/*

	 * By LoongArch Reference Manual 2.2.10.5

	 * Return value is 0 for undefined CPUCFG index

	 *

	 * Disable preemption since hw gcsr is accessed

	 */

	preempt_disable();

	switch (index) {

	case 0 ... (KVM_MAX_CPUCFG_REGS - 1):

		vcpu->arch.gprs[rd] = vcpu->arch.cpucfg[index];

		break;

	case CPUCFG_KVM_SIG:

		/* CPUCFG emulation between 0x40000000 -- 0x400000ff */

		vcpu->arch.gprs[rd] = *(unsigned int *)KVM_SIGNATURE;

		break;

	case CPUCFG_KVM_FEATURE:

		ret = vcpu->kvm->arch.pv_features & LOONGARCH_PV_FEAT_MASK;

		vcpu->arch.gprs[rd] = ret;

		break;

	default:

		vcpu->arch.gprs[rd] = 0;

		break;

	}

	preempt_enable();



	return EMULATE_DONE;

}



static unsigned long kvm_emu_read_csr(struct kvm_vcpu *vcpu, int csrid)

{

	unsigned long val = 0;
@@ -225,52 +266,6 @@ int kvm_emu_idle(struct kvm_vcpu *vcpu) 
	return EMULATE_DONE;

}



static int kvm_emu_cpucfg(struct kvm_vcpu *vcpu, larch_inst inst)

{

	int rd, rj;

	unsigned int index, ret;

	unsigned long plv;



	rd = inst.reg2_format.rd;

	rj = inst.reg2_format.rj;

	++vcpu->stat.cpucfg_exits;

	index = vcpu->arch.gprs[rj];



	/*

	 * By LoongArch Reference Manual 2.2.10.5

	 * Return value is 0 for undefined cpucfg index

	 *

	 * Disable preemption since hw gcsr is accessed

	 */

	preempt_disable();

	plv = kvm_read_hw_gcsr(LOONGARCH_CSR_CRMD) >> CSR_CRMD_PLV_SHIFT;

	switch (index) {

	case 0 ... (KVM_MAX_CPUCFG_REGS - 1):

		vcpu->arch.gprs[rd] = vcpu->arch.cpucfg[index];

		break;

	case CPUCFG_KVM_SIG:

		/*

		 * Cpucfg emulation between 0x40000000 -- 0x400000ff

		 * Return value with 0 if executed in user mode

		 */

		if ((plv & CSR_CRMD_PLV) == PLV_KERN)

			vcpu->arch.gprs[rd] = *(unsigned int *)KVM_SIGNATURE;

		else

			vcpu->arch.gprs[rd] = 0;

		break;

	case CPUCFG_KVM_FEATURE:

		ret = vcpu->kvm->arch.pv_features & LOONGARCH_PV_FEAT_MASK;

		vcpu->arch.gprs[rd] = ret;

		break;

	default:

		vcpu->arch.gprs[rd] = 0;

		break;

	}



	preempt_enable();

	return EMULATE_DONE;

}



static int kvm_trap_handle_gspr(struct kvm_vcpu *vcpu)

{

	unsigned long curr_pc;
@@ -287,7 +282,6 @@ static int kvm_trap_handle_gspr(struct kvm_vcpu *vcpu) 
	er = EMULATE_FAIL;

	switch (((inst.word >> 24) & 0xff)) {

	case 0x0: /* CPUCFG GSPR */

		if (inst.reg2_format.opcode == cpucfg_op)

		er = kvm_emu_cpucfg(vcpu, inst);

		break;

	case 0x4: /* CSR{RD,WR,XCHG} GSPR */