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@xxxxxxxxxxx>
Tested-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
---
arch/loongarch/kvm/exit.c | 105 ++++++++++++++++++++++++++++++++++++++
1 file changed, 105 insertions(+)
create mode 100644 arch/loongarch/kvm/exit.c
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
new file mode 100644
index 0000000000..37bc8a4209
--- /dev/null
+++ b/arch/loongarch/kvm/exit.c
@@ -0,0 +1,105 @@
+// 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;
+}
--
2.39.3
