[PATCH v2 21/29] LoongArch: KVM: Implement handle iocsr exception

From: Tianrui Zhao
Date: Mon Feb 20 2023 - 01:58:51 EST


Implement kvm handle vcpu iocsr exception, setting the iocsr info into
vcpu_run and return to user space to handle it.

Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
arch/loongarch/include/asm/inst.h | 16 ++++++
arch/loongarch/kvm/exit.c | 92 +++++++++++++++++++++++++++++++
2 files changed, 108 insertions(+)

diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h
index 7eedd83fd..8ed137814 100644
--- a/arch/loongarch/include/asm/inst.h
+++ b/arch/loongarch/include/asm/inst.h
@@ -50,6 +50,14 @@ enum reg2_op {
revbd_op = 0x0f,
revh2w_op = 0x10,
revhd_op = 0x11,
+ iocsrrdb_op = 0x19200,
+ iocsrrdh_op = 0x19201,
+ iocsrrdw_op = 0x19202,
+ iocsrrdd_op = 0x19203,
+ iocsrwrb_op = 0x19204,
+ iocsrwrh_op = 0x19205,
+ iocsrwrw_op = 0x19206,
+ iocsrwrd_op = 0x19207,
};

enum reg2i5_op {
@@ -261,6 +269,13 @@ struct reg3sa2_format {
unsigned int opcode : 15;
};

+struct reg2csr_format {
+ unsigned int rd : 5;
+ unsigned int rj : 5;
+ unsigned int csr : 14;
+ unsigned int opcode : 8;
+};
+
union loongarch_instruction {
unsigned int word;
struct reg0i26_format reg0i26_format;
@@ -275,6 +290,7 @@ union loongarch_instruction {
struct reg2bstrd_format reg2bstrd_format;
struct reg3_format reg3_format;
struct reg3sa2_format reg3sa2_format;
+ struct reg2csr_format reg2csr_format;
};

#define LOONGARCH_INSN_SIZE sizeof(union loongarch_instruction)
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index dc37827d9..f02e2b940 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -99,3 +99,95 @@ static int _kvm_handle_csr(struct kvm_vcpu *vcpu, larch_inst inst)

return EMULATE_DONE;
}
+
+int _kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+ u32 rd, rj, opcode;
+ u32 addr;
+ unsigned long val;
+ int ret;
+
+ /*
+ * 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)
+{
+ unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
+ enum emulation_result er = EMULATE_DONE;
+
+ switch (run->iocsr_io.len) {
+ case 8:
+ *gpr = *(s64 *)run->iocsr_io.data;
+ break;
+ case 4:
+ *gpr = *(int *)run->iocsr_io.data;
+ break;
+ case 2:
+ *gpr = *(short *)run->iocsr_io.data;
+ break;
+ case 1:
+ *gpr = *(char *) run->iocsr_io.data;
+ break;
+ default:
+ kvm_err("Bad IOCSR length: %d,addr is 0x%lx",
+ run->iocsr_io.len, vcpu->arch.badv);
+ er = EMULATE_FAIL;
+ break;
+ }
+
+ return er;
+}
--
2.31.1