Add support in KVM SBI FWFT extension to allow VS-mode to request double
trap enabling. Double traps can then be generated by VS-mode, allowing
M-mode to redirect them to S-mode.
Signed-off-by: Clément Léger <cleger@xxxxxxxxxxxx>
---
arch/riscv/include/asm/csr.h | 1 +
arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 2 +-
arch/riscv/kvm/vcpu_sbi_fwft.c | 41 ++++++++++++++++++++++
3 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 905cdf894a57..ee1b73655bec 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -196,6 +196,7 @@
/* xENVCFG flags */
#define ENVCFG_STCE (_AC(1, ULL) << 63)
#define ENVCFG_PBMTE (_AC(1, ULL) << 62)
+#define ENVCFG_DTE (_AC(1, ULL) << 59)
#define ENVCFG_CBZE (_AC(1, UL) << 7)
#define ENVCFG_CBCFE (_AC(1, UL) << 6)
#define ENVCFG_CBIE_SHIFT 4
diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
index 7dc1b80c7e6c..a9e20d655126 100644
--- a/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
@@ -11,7 +11,7 @@
#include <asm/sbi.h>
-#define KVM_SBI_FWFT_FEATURE_COUNT 1
+#define KVM_SBI_FWFT_FEATURE_COUNT 2
struct kvm_sbi_fwft_config;
struct kvm_vcpu;
diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c
index b9b7f8fa6d22..9e8e397eb02f 100644
--- a/arch/riscv/kvm/vcpu_sbi_fwft.c
+++ b/arch/riscv/kvm/vcpu_sbi_fwft.c
@@ -9,10 +9,19 @@
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
+#include <linux/riscv_dbltrp.h>
#include <asm/sbi.h>
#include <asm/kvm_vcpu_sbi.h>
#include <asm/kvm_vcpu_sbi_fwft.h>
+#ifdef CONFIG_32BIT
+# define CSR_HENVCFG_DBLTRP CSR_HENVCFGH
+# define DBLTRP_DTE (ENVCFG_DTE >> 32)
+#else
+# define CSR_HENVCFG_DBLTRP CSR_HENVCFG
+# define DBLTRP_DTE ENVCFG_DTE
+#endif
+
#define MIS_DELEG (1UL << EXC_LOAD_MISALIGNED | 1UL << EXC_STORE_MISALIGNED)
static int kvm_sbi_fwft_set_misaligned_delegation(struct kvm_vcpu *vcpu,
@@ -36,6 +45,33 @@ static int kvm_sbi_fwft_get_misaligned_delegation(struct kvm_vcpu *vcpu,
return SBI_SUCCESS;
}
+static int kvm_sbi_fwft_set_double_trap(struct kvm_vcpu *vcpu,
+ struct kvm_sbi_fwft_config *conf,
+ unsigned long value)
+{
+ if (!riscv_double_trap_enabled())
+ return SBI_ERR_NOT_SUPPORTED;
+
+ if (value)
+ csr_set(CSR_HENVCFG_DBLTRP, DBLTRP_DTE);
+ else
+ csr_clear(CSR_HENVCFG_DBLTRP, DBLTRP_DTE);
+
+ return SBI_SUCCESS;
+}
+
+static int kvm_sbi_fwft_get_double_trap(struct kvm_vcpu *vcpu,
+ struct kvm_sbi_fwft_config *conf,
+ unsigned long *value)
+{
+ if (!riscv_double_trap_enabled())
+ return SBI_ERR_NOT_SUPPORTED;
+
+ *value = (csr_read(CSR_HENVCFG_DBLTRP) & DBLTRP_DTE) != 0;
+
+ return SBI_SUCCESS;
+}
+
static struct kvm_sbi_fwft_config *
kvm_sbi_fwft_get_config(struct kvm_vcpu *vcpu, enum sbi_fwft_feature_t feature)
{
@@ -111,6 +147,11 @@ static const struct kvm_sbi_fwft_feature features[] = {
.id = SBI_FWFT_MISALIGNED_DELEG,
.set = kvm_sbi_fwft_set_misaligned_delegation,
.get = kvm_sbi_fwft_get_misaligned_delegation,
+ },
+ {
+ .id = SBI_FWFT_DOUBLE_TRAP_ENABLE,
+ .set = kvm_sbi_fwft_set_double_trap,
+ .get = kvm_sbi_fwft_get_double_trap,
}
};
--
2.43.0
