[PATCH v4 4/7] RISC-V: KVM: Enable Smstateen accesses

[Mayuresh Chitale <mchitale@xxxxxxxxxxxxxxxx>]

Configure hstateen0 register so that the AIA state and envcfg are
accessible to the vcpus. This includes registers such as siselect,
sireg, siph, sieh and all the IMISC registers.

Signed-off-by: Mayuresh Chitale <mchitale@xxxxxxxxxxxxxxxx>
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
---
 arch/riscv/include/asm/csr.h      | 16 ++++++++++++++++
 arch/riscv/include/asm/kvm_host.h |  1 +
 arch/riscv/include/uapi/asm/kvm.h |  1 +
 arch/riscv/kvm/vcpu.c             | 15 +++++++++++++++
 4 files changed, 33 insertions(+)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index 7bac43a3176e..38730677dcd5 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -201,6 +201,18 @@
 #define ENVCFG_CBIE_INV			_AC(0x3, UL)
 #define ENVCFG_FIOM			_AC(0x1, UL)
 
+/* Smstateen bits */
+#define SMSTATEEN0_AIA_IMSIC_SHIFT	58
+#define SMSTATEEN0_AIA_IMSIC		(_ULL(1) << SMSTATEEN0_AIA_IMSIC_SHIFT)
+#define SMSTATEEN0_AIA_SHIFT		59
+#define SMSTATEEN0_AIA			(_ULL(1) << SMSTATEEN0_AIA_SHIFT)
+#define SMSTATEEN0_AIA_ISEL_SHIFT	60
+#define SMSTATEEN0_AIA_ISEL		(_ULL(1) << SMSTATEEN0_AIA_ISEL_SHIFT)
+#define SMSTATEEN0_HSENVCFG_SHIFT	62
+#define SMSTATEEN0_HSENVCFG		(_ULL(1) << SMSTATEEN0_HSENVCFG_SHIFT)
+#define SMSTATEEN0_SSTATEEN0_SHIFT	63
+#define SMSTATEEN0_SSTATEEN0		(_ULL(1) << SMSTATEEN0_SSTATEEN0_SHIFT)
+
 /* symbolic CSR names: */
 #define CSR_CYCLE		0xc00
 #define CSR_TIME		0xc01
@@ -347,6 +359,10 @@
 #define CSR_VSIEH		0x214
 #define CSR_VSIPH		0x254
 
+/* Hypervisor stateen CSRs */
+#define CSR_HSTATEEN0		0x60c
+#define CSR_HSTATEEN0H		0x61c
+
 #define CSR_MSTATUS		0x300
 #define CSR_MISA		0x301
 #define CSR_MIDELEG		0x303
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index c0fb54d164c7..d00b61620f54 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -166,6 +166,7 @@ struct kvm_vcpu_csr {
 
 struct kvm_vcpu_config {
 	u64 henvcfg;
+	u64 hstateen0;
 };
 
 struct kvm_vcpu_arch {
diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 9c35e1427f73..dc185e7875ce 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -130,6 +130,7 @@ enum KVM_RISCV_ISA_EXT_ID {
 	KVM_RISCV_ISA_EXT_ZICSR,
 	KVM_RISCV_ISA_EXT_ZIFENCEI,
 	KVM_RISCV_ISA_EXT_ZIHPM,
+	KVM_RISCV_ISA_EXT_SMSTATEEN,
 	KVM_RISCV_ISA_EXT_MAX,
 };
 
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 43d955eca286..7ce250087aed 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -469,6 +469,16 @@ static void kvm_riscv_vcpu_setup_config(struct kvm_vcpu *vcpu)
 
 	if (riscv_isa_extension_available(isa, ZICBOZ))
 		cfg->henvcfg |= ENVCFG_CBZE;
+
+	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN)) {
+		cfg->hstateen0 |= SMSTATEEN0_HSENVCFG;
+		if (riscv_isa_extension_available(isa, SSAIA))
+			cfg->hstateen0 |= SMSTATEEN0_AIA_IMSIC |
+					  SMSTATEEN0_AIA |
+					  SMSTATEEN0_AIA_ISEL;
+		if (riscv_isa_extension_available(isa, SMSTATEEN))
+			cfg->hstateen0 |= SMSTATEEN0_SSTATEEN0;
+	}
 }
 
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
@@ -488,6 +498,11 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	csr_write(CSR_HENVCFG, cfg->henvcfg);
 	if (IS_ENABLED(CONFIG_32BIT))
 		csr_write(CSR_HENVCFGH, cfg->henvcfg >> 32);
+	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN)) {
+		csr_write(CSR_HSTATEEN0, cfg->hstateen0);
+		if (IS_ENABLED(CONFIG_32BIT))
+			csr_write(CSR_HSTATEEN0H, cfg->hstateen0 >> 32);
+	}
 
 	kvm_riscv_gstage_update_hgatp(vcpu);
 
-- 
2.34.1