[PATCH v1 05/14] RISC-V: KVM: Add SBI STA extension skeleton

Andrew Jones
2023-12-05T18:11:42Z

Add the files and functions needed to support the SBI STA
(steal-time accounting) extension. In the next patches we'll
complete the functions to fully enable SBI STA support.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 +
arch/riscv/include/uapi/asm/kvm.h | 1 +
arch/riscv/kvm/Makefile | 1 +
arch/riscv/kvm/vcpu_sbi.c | 4 +++
arch/riscv/kvm/vcpu_sbi_sta.c | 47 +++++++++++++++++++++++++++
5 files changed, 54 insertions(+)
create mode 100644 arch/riscv/kvm/vcpu_sbi_sta.c

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index bffda0ac59b6..99c23bb37a37 100644
--- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -76,6 +76,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn;
+extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor;

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 909bd98220ee..85b979f7d2bd 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -184,6 +184,7 @@ enum KVM_RISCV_SBI_EXT_ID {
KVM_RISCV_SBI_EXT_EXPERIMENTAL,
KVM_RISCV_SBI_EXT_VENDOR,
KVM_RISCV_SBI_EXT_DBCN,
+ KVM_RISCV_SBI_EXT_STA,
KVM_RISCV_SBI_EXT_MAX,
};

diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 4c2067fc59fc..c9646521f113 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -26,6 +26,7 @@ kvm-$(CONFIG_RISCV_SBI_V01) += vcpu_sbi_v01.o
kvm-y += vcpu_sbi_base.o
kvm-y += vcpu_sbi_replace.o
kvm-y += vcpu_sbi_hsm.o
+kvm-y += vcpu_sbi_sta.o
kvm-y += vcpu_timer.o
kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
kvm-y += aia.o
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index dcdff4458190..088daaa23dd8 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -70,6 +70,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = {
.ext_idx = KVM_RISCV_SBI_EXT_DBCN,
.ext_ptr = &vcpu_sbi_ext_dbcn,
},
+ {
+ .ext_idx = KVM_RISCV_SBI_EXT_STA,
+ .ext_ptr = &vcpu_sbi_ext_sta,
+ },
{
.ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL,
.ext_ptr = &vcpu_sbi_ext_experimental,
diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c
new file mode 100644
index 000000000000..839911dcd837
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_sbi_sta.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ */
+
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_vcpu_sbi.h>
+#include <asm/sbi.h>
+
+static int kvm_sbi_sta_steal_time_set_shmem(struct kvm_vcpu *vcpu)
+{
+ return SBI_ERR_FAILURE;
+}
+
+static int kvm_sbi_ext_sta_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ struct kvm_vcpu_sbi_return *retdata)
+{
+ struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+ unsigned long funcid = cp->a6;
+ int ret;
+
+ switch (funcid) {
+ case SBI_EXT_STA_STEAL_TIME_SET_SHMEM:
+ ret = kvm_sbi_sta_steal_time_set_shmem(vcpu);
+ break;
+ default:
+ ret = SBI_ERR_NOT_SUPPORTED;
+ break;
+ }
+
+ retdata->err_val = ret;
+
+ return 0;
+}
+
+static unsigned long kvm_sbi_ext_sta_probe(struct kvm_vcpu *vcpu)
+{
+ return 0;
+}
+
+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta = {
+ .extid_start = SBI_EXT_STA,
+ .extid_end = SBI_EXT_STA,
+ .handler = kvm_sbi_ext_sta_handler,
+ .probe = kvm_sbi_ext_sta_probe,
+};