Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2025-01-17 18:56:24 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

LoongArch: KVM: Add cpucfg area for kvm hypervisor

Browse Source 
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: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Bibo Mao 2024-05-06 22:00:47 +08:00 committed by Huacai Chen
parent 372631bb62
commit 9753d30379
3 changed files with 50 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/loongarch/include/asm/inst.h
View File

@ -67,6 +67,7 @@ enum reg2_op {
revhd_op = 0x11,
extwh_op = 0x16,
extwb_op = 0x17,
cpucfg_op = 0x1b,
iocsrrdb_op = 0x19200,
iocsrrdh_op = 0x19201,
iocsrrdw_op = 0x19202,

11
arch/loongarch/include/asm/loongarch.h
View File

@ -158,6 +158,17 @@
#define CPUCFG48_VFPU_CG BIT(2)
#define CPUCFG48_RAM_CG BIT(3)
/*
* CPUCFG index area: 0x40000000 -- 0x400000ff
* SW emulation for KVM hypervirsor
*/
#define CPUCFG_KVM_BASE 0x40000000
#define CPUCFG_KVM_SIZE 0x100
#define CPUCFG_KVM_SIG (CPUCFG_KVM_BASE + 0)
#define KVM_SIGNATURE "KVM\0"
#define CPUCFG_KVM_FEATURE (CPUCFG_KVM_BASE + 4)
#ifndef __ASSEMBLY__
/* CSR */

55
arch/loongarch/kvm/exit.c
View File

@ -20,6 +20,43 @@
#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;
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;
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;
@ -208,8 +245,6 @@ int kvm_emu_idle(struct kvm_vcpu *vcpu)
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;
@ -224,21 +259,7 @@ 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 == 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;
}
er = kvm_emu_cpucfg(vcpu, inst);
break;
case 0x4: /* CSR{RD,WR,XCHG} GSPR */
er = kvm_handle_csr(vcpu, inst);