[PATCH v8 3/5] RISC-V: KVM: Add Svade and Svadu Extensions Support for Guest/VM

Yong-Xuan Wang
2024-07-26T08:49:55Z

We extend the KVM ISA extension ONE_REG interface to allow VMM tools to
detect and enable Svade and Svadu extensions for Guest/VM. Since the
henvcfg.ADUE is read-only zero if the menvcfg.ADUE is zero, the Svadu
extension is available for Guest/VM and the Svade extension is allowed
to disabledonly when arch_has_hw_pte_young() is true.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
---
arch/riscv/include/uapi/asm/kvm.h | 2 ++
arch/riscv/kvm/vcpu.c | 4 ++++
arch/riscv/kvm/vcpu_onereg.c | 15 +++++++++++++++
3 files changed, 21 insertions(+)

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index e97db3296456..85bbc472989d 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -175,6 +175,8 @@ enum KVM_RISCV_ISA_EXT_ID {
KVM_RISCV_ISA_EXT_ZCF,
KVM_RISCV_ISA_EXT_ZCMOP,
KVM_RISCV_ISA_EXT_ZAWRS,
+ KVM_RISCV_ISA_EXT_SVADE,
+ KVM_RISCV_ISA_EXT_SVADU,
KVM_RISCV_ISA_EXT_MAX,
};

diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 8d7d381737ee..c78061a6d68b 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -544,6 +544,10 @@ static void kvm_riscv_vcpu_setup_config(struct kvm_vcpu *vcpu)
if (riscv_isa_extension_available(isa, ZICBOZ))
cfg->henvcfg |= ENVCFG_CBZE;

+ if (riscv_isa_extension_available(isa, SVADU) &&
+ !riscv_isa_extension_available(isa, SVADE))
+ cfg->henvcfg |= ENVCFG_ADUE;
+
if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN)) {
cfg->hstateen0 |= SMSTATEEN0_HSENVCFG;
if (riscv_isa_extension_available(isa, SSAIA))
diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
index b319c4c13c54..b3f58908902a 100644
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
@@ -15,6 +15,7 @@
#include <asm/cacheflush.h>
#include <asm/cpufeature.h>
#include <asm/kvm_vcpu_vector.h>
+#include <asm/pgtable.h>
#include <asm/vector.h>

#define KVM_RISCV_BASE_ISA_MASK GENMASK(25, 0)
@@ -38,6 +39,8 @@ static const unsigned long kvm_isa_ext_arr[] = {
KVM_ISA_EXT_ARR(SSAIA),
KVM_ISA_EXT_ARR(SSCOFPMF),
KVM_ISA_EXT_ARR(SSTC),
+ KVM_ISA_EXT_ARR(SVADE),
+ KVM_ISA_EXT_ARR(SVADU),
KVM_ISA_EXT_ARR(SVINVAL),
KVM_ISA_EXT_ARR(SVNAPOT),
KVM_ISA_EXT_ARR(SVPBMT),
@@ -110,6 +113,12 @@ static bool kvm_riscv_vcpu_isa_enable_allowed(unsigned long ext)
case KVM_RISCV_ISA_EXT_SSCOFPMF:
/* Sscofpmf depends on interrupt filtering defined in ssaia */
return __riscv_isa_extension_available(NULL, RISCV_ISA_EXT_SSAIA);
+ case KVM_RISCV_ISA_EXT_SVADU:
+ /*
+ * The henvcfg.ADUE is read-only zero if menvcfg.ADUE is zero.
+ * Guest OS can use Svadu only when host OS enable Svadu.
+ */
+ return arch_has_hw_pte_young();
case KVM_RISCV_ISA_EXT_V:
return riscv_v_vstate_ctrl_user_allowed();
default:
@@ -181,6 +190,12 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
/* Extensions which can be disabled using Smstateen */
case KVM_RISCV_ISA_EXT_SSAIA:
return riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN);
+ case KVM_RISCV_ISA_EXT_SVADE:
+ /*
+ * The henvcfg.ADUE is read-only zero if menvcfg.ADUE is zero.
+ * Svade is not allowed to disable when the platform use Svade.
+ */
+ return arch_has_hw_pte_young();
default:
break;
}
--
2.17.1