On 4/24/25 10:31 AM, Clément Léger wrote:

The Firmware Features extension (FWFT) was added as part of the SBI 3.0 specification. Add SBI definitions to use this extension.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Samuel Holland samuel.holland@sifive.com Tested-by: Samuel Holland samuel.holland@sifive.com Reviewed-by: Deepak Gupta debug@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/sbi.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 3d250824178b..bb077d0c912f 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -35,6 +35,7 @@ enum sbi_ext_id { SBI_EXT_DBCN = 0x4442434E, SBI_EXT_STA = 0x535441, SBI_EXT_NACL = 0x4E41434C,

• SBI_EXT_FWFT = 0x46574654,

/* Experimentals extensions must lie within this range */ SBI_EXT_EXPERIMENTAL_START = 0x08000000, @@ -402,6 +403,33 @@ enum sbi_ext_nacl_feature { #define SBI_NACL_SHMEM_SRET_X(__i) ((__riscv_xlen / 8) * (__i)) #define SBI_NACL_SHMEM_SRET_X_LAST 31 +/* SBI function IDs for FW feature extension */ +#define SBI_EXT_FWFT_SET 0x0 +#define SBI_EXT_FWFT_GET 0x1

+enum sbi_fwft_feature_t {

• SBI_FWFT_MISALIGNED_EXC_DELEG = 0x0,
• SBI_FWFT_LANDING_PAD = 0x1,
• SBI_FWFT_SHADOW_STACK = 0x2,
• SBI_FWFT_DOUBLE_TRAP = 0x3,
• SBI_FWFT_PTE_AD_HW_UPDATING = 0x4,
• SBI_FWFT_POINTER_MASKING_PMLEN = 0x5,
• SBI_FWFT_LOCAL_RESERVED_START = 0x6,
• SBI_FWFT_LOCAL_RESERVED_END = 0x3fffffff,
• SBI_FWFT_LOCAL_PLATFORM_START = 0x40000000,
• SBI_FWFT_LOCAL_PLATFORM_END = 0x7fffffff,
• SBI_FWFT_GLOBAL_RESERVED_START = 0x80000000,
• SBI_FWFT_GLOBAL_RESERVED_END = 0xbfffffff,
• SBI_FWFT_GLOBAL_PLATFORM_START = 0xc0000000,
• SBI_FWFT_GLOBAL_PLATFORM_END = 0xffffffff,

+};

+#define SBI_FWFT_PLATFORM_FEATURE_BIT BIT(30) +#define SBI_FWFT_GLOBAL_FEATURE_BIT BIT(31)

+#define SBI_FWFT_SET_FLAG_LOCK BIT(0)

• /* SBI spec version fields */ #define SBI_SPEC_VERSION_DEFAULT 0x1 #define SBI_SPEC_VERSION_MAJOR_SHIFT 24

@@ -419,6 +447,11 @@ enum sbi_ext_nacl_feature { #define SBI_ERR_ALREADY_STARTED -7 #define SBI_ERR_ALREADY_STOPPED -8 #define SBI_ERR_NO_SHMEM -9 +#define SBI_ERR_INVALID_STATE -10 +#define SBI_ERR_BAD_RANGE -11 +#define SBI_ERR_TIMEOUT -12 +#define SBI_ERR_IO -13 +#define SBI_ERR_DENIED_LOCKED -14 extern unsigned long sbi_spec_version; struct sbiret {

Reviewed-by: Atish Patra atishp@rivosinc.com

On Thu, Apr 24, 2025 at 07:31:49PM +0200, Clément Léger wrote:

A few parenthesis in check for SBI version/extension were useless, remove them.

Signed-off-by: Clément Léger cleger@rivosinc.com

arch/riscv/kernel/sbi.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 1989b8cade1b..1d44c35305a9 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -609,7 +609,7 @@ void __init sbi_init(void) } else { __sbi_rfence = __sbi_rfence_v01; }

• if ((sbi_spec_version >= sbi_mk_version(0, 3)) &&
  

• if (sbi_spec_version >= sbi_mk_version(0, 3) &&
  

  sbi_probe_extension(SBI_EXT_SRST)) { pr_info("SBI SRST extension detected\n"); pm_power_off = sbi_srst_power_off;

@@ -617,8 +617,8 @@ void __init sbi_init(void) sbi_srst_reboot_nb.priority = 192; register_restart_handler(&sbi_srst_reboot_nb); }

• if ((sbi_spec_version >= sbi_mk_version(2, 0)) &&
  

•     (sbi_probe_extension(SBI_EXT_DBCN) > 0)) {
  

• if (sbi_spec_version >= sbi_mk_version(2, 0) &&
  

•     sbi_probe_extension(SBI_EXT_DBCN) > 0) {
  pr_info("SBI DBCN extension detected\n");
  sbi_debug_console_available = true;
  

  }

-- 2.49.0

Reviewed-by: Andrew Jones ajones@ventanamicro.com

On 4/24/25 10:31 AM, Clément Léger wrote:

This SBI extensions enables supervisor mode to control feature that are under M-mode control (For instance, Svadu menvcfg ADUE bit, Ssdbltrp DTE, etc). Add an interface to set local features for a specific cpu mask as well as for the online cpu mask.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/sbi.h | 17 +++++++++++ arch/riscv/kernel/sbi.c | 57 ++++++++++++++++++++++++++++++++++++ 2 files changed, 74 insertions(+)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 7ec249fea880..3bbef56bcefc 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -503,6 +503,23 @@ int sbi_remote_hfence_vvma_asid(const struct cpumask *cpu_mask, unsigned long asid); long sbi_probe_extension(int ext); +int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags); +int sbi_fwft_set_cpumask(const cpumask_t *mask, u32 feature,

• 	 unsigned long value, unsigned long flags);
  

+/**

• • sbi_fwft_set_online_cpus() - Set a feature on all online cpus
• • @feature: The feature to be set
• • @value: The feature value to be set
• • @flags: FWFT feature set flags
• • Return: 0 on success, appropriate linux error code otherwise.
• */

+static inline int sbi_fwft_set_online_cpus(u32 feature, unsigned long value,

• 			   unsigned long flags)
  

+{

• return sbi_fwft_set_cpumask(cpu_online_mask, feature, value, flags);

+}

• /* Check if current SBI specification version is 0.1 or not */ static inline int sbi_spec_is_0_1(void) {

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 1d44c35305a9..d57e4dae7dac 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -299,6 +299,63 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, return 0; } +/**

• • sbi_fwft_set() - Set a feature on the local hart
• • @feature: The feature ID to be set
• • @value: The feature value to be set
• • @flags: FWFT feature set flags
• • Return: 0 on success, appropriate linux error code otherwise.
• */

+int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags) +{

• return -EOPNOTSUPP;

+}

+struct fwft_set_req {

• u32 feature;
• unsigned long value;
• unsigned long flags;
• atomic_t error;

+};

+static void cpu_sbi_fwft_set(void *arg) +{

• struct fwft_set_req *req = arg;
• int ret;
• ret = sbi_fwft_set(req->feature, req->value, req->flags);
• if (ret)

• atomic_set(&req->error, ret);
  

What happens when cpuX executed first reported an error but cpuY executed this function later and report success.

The error will be masked in that case.

+}

+/**

• • sbi_fwft_set_cpumask() - Set a feature for the specified cpumask
• • @mask: CPU mask of cpus that need the feature to be set
• • @feature: The feature ID to be set
• • @value: The feature value to be set
• • @flags: FWFT feature set flags
• • Return: 0 on success, appropriate linux error code otherwise.
• */

+int sbi_fwft_set_cpumask(const cpumask_t *mask, u32 feature,

• 	       unsigned long value, unsigned long flags)
  

+{

• struct fwft_set_req req = {

• .feature = feature,
  

• .value = value,
  

• .flags = flags,
  

• .error = ATOMIC_INIT(0),
  

• };
• if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT)

• return -EINVAL;
  

• on_each_cpu_mask(mask, cpu_sbi_fwft_set, &req, 1);
• return atomic_read(&req.error);

+}

• /**
  • sbi_set_timer() - Program the timer for next timer event.
  • @stime_value: The value after which next timer event should fire.

On 5/12/25 1:14 AM, Clément Léger wrote:

On 09/05/2025 02:18, Atish Patra wrote:

...

On 4/24/25 10:31 AM, Clément Léger wrote:

...

This SBI extensions enables supervisor mode to control feature that are under M-mode control (For instance, Svadu menvcfg ADUE bit, Ssdbltrp DTE, etc). Add an interface to set local features for a specific cpu mask as well as for the online cpu mask.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/sbi.h | 17 +++++++++++   arch/riscv/kernel/sbi.c      | 57 ++++++++++++++++++++++++++++++++++++   2 files changed, 74 insertions(+)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 7ec249fea880..3bbef56bcefc 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -503,6 +503,23 @@ int sbi_remote_hfence_vvma_asid(const struct cpumask *cpu_mask,                   unsigned long asid);   long sbi_probe_extension(int ext);   +int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags); +int sbi_fwft_set_cpumask(const cpumask_t *mask, u32 feature, +             unsigned long value, unsigned long flags); +/**

• • sbi_fwft_set_online_cpus() - Set a feature on all online cpus
• • @feature: The feature to be set
• • @value: The feature value to be set
• • @flags: FWFT feature set flags
• • Return: 0 on success, appropriate linux error code otherwise.
• */

+static inline int sbi_fwft_set_online_cpus(u32 feature, unsigned long value, +                       unsigned long flags) +{ +    return sbi_fwft_set_cpumask(cpu_online_mask, feature, value, flags); +}

/* Check if current SBI specification version is 0.1 or not */   static inline int sbi_spec_is_0_1(void)   { diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 1d44c35305a9..d57e4dae7dac 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -299,6 +299,63 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask,       return 0;   }   +/**

• • sbi_fwft_set() - Set a feature on the local hart
• • @feature: The feature ID to be set
• • @value: The feature value to be set
• • @flags: FWFT feature set flags
• • Return: 0 on success, appropriate linux error code otherwise.
• */

+int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags) +{ +    return -EOPNOTSUPP; +}

+struct fwft_set_req { +    u32 feature; +    unsigned long value; +    unsigned long flags; +    atomic_t error; +};

+static void cpu_sbi_fwft_set(void *arg) +{ +    struct fwft_set_req *req = arg; +    int ret;

+    ret = sbi_fwft_set(req->feature, req->value, req->flags); +    if (ret) +        atomic_set(&req->error, ret);

What happens when cpuX executed first reported an error but cpuY executed this function later and report success.

The error will be masked in that case.

We actually only set the bit if an error happened (consider it as a sticky error bit). So if CPUy reports success, it won't clear the bit.

Ahh yes. I missed that.

Thanks,

Clément

...

...

+}

+/**

• • sbi_fwft_set_cpumask() - Set a feature for the specified cpumask
• • @mask: CPU mask of cpus that need the feature to be set
• • @feature: The feature ID to be set
• • @value: The feature value to be set
• • @flags: FWFT feature set flags
• • Return: 0 on success, appropriate linux error code otherwise.
• */

+int sbi_fwft_set_cpumask(const cpumask_t *mask, u32 feature, +                   unsigned long value, unsigned long flags) +{ +    struct fwft_set_req req = { +        .feature = feature, +        .value = value, +        .flags = flags, +        .error = ATOMIC_INIT(0), +    };

+    if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT) +        return -EINVAL;

+    on_each_cpu_mask(mask, cpu_sbi_fwft_set, &req, 1);

+    return atomic_read(&req.error); +}

/**    * sbi_set_timer() - Program the timer for next timer event.    * @stime_value: The value after which next timer event should fire.

On 4/24/25 10:31 AM, Clément Léger wrote:

Add FWFT extension calls. This will be ratified in SBI V3.0 hence, it is provided as a separate commit that can be left out if needed.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/kernel/sbi.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index d57e4dae7dac..070014ff35d4 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -299,6 +299,8 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, return 0; } +static bool sbi_fwft_supported;

super nit: Can declare this along with struct fwft_set_req so that they are together ? You can move the sbi_fwft_set to below the struct fwft_set_req.

/**

• sbi_fwft_set() - Set a feature on the local hart
• @feature: The feature ID to be set

@@ -309,7 +311,15 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, */ int sbi_fwft_set(u32 feature, unsigned long value, unsigned long flags) {

• return -EOPNOTSUPP;

• struct sbiret ret;
• if (!sbi_fwft_supported)

• return -EOPNOTSUPP;
  

• ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET,

• 	feature, value, flags, 0, 0, 0);
  

• return sbi_err_map_linux_errno(ret.error); }

struct fwft_set_req { @@ -348,6 +358,9 @@ int sbi_fwft_set_cpumask(const cpumask_t *mask, u32 feature, .error = ATOMIC_INIT(0), };

• if (!sbi_fwft_supported)

• return -EOPNOTSUPP;
  

• if (feature & SBI_FWFT_GLOBAL_FEATURE_BIT) return -EINVAL;

@@ -679,6 +692,11 @@ void __init sbi_init(void) pr_info("SBI DBCN extension detected\n"); sbi_debug_console_available = true; }

• if (sbi_spec_version >= sbi_mk_version(3, 0) &&
  

•     sbi_probe_extension(SBI_EXT_FWFT)) {
  

• 	pr_info("SBI FWFT extension detected\n");
  

• 	sbi_fwft_supported = true;
  

• }
  

  } else { __sbi_set_timer = __sbi_set_timer_v01; __sbi_send_ipi = __sbi_send_ipi_v01;

Otherwise, LGTM.

Reviewed-by: Atish Patra atishp@rivosinc.com

On Thu, 24 Apr 2025 10:31:58 PDT (-0700), cleger@rivosinc.com wrote:

The FWFT SBI extension will need to dynamically allocate memory and do init time specific initialization. Add an init/deinit callbacks that allows to do so.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/kvm_vcpu_sbi.h | 9 +++++++++ arch/riscv/kvm/vcpu.c | 2 ++ arch/riscv/kvm/vcpu_sbi.c | 26 ++++++++++++++++++++++++++ 3 files changed, 37 insertions(+)

There's 4 KVM patches in here without an Ack from Atish or Anup. They're all tied up in the SBIv3 stuff, so just LMK if you want me to take them into that staging branch or if you want me to wait.

For now I'm going to go look at other stuff, no rush on my end.

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index 4ed6203cdd30..bcb90757b149 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -49,6 +49,14 @@ struct kvm_vcpu_sbi_extension {

/* Extension specific probe function */ unsigned long (*probe)(struct kvm_vcpu *vcpu);

• /*

• * Init/deinit function called once during VCPU init/destroy. These
  

• * might be use if the SBI extensions need to allocate or do specific
  

• * init time only configuration.
  

• */
  

• int (*init)(struct kvm_vcpu *vcpu);
• void (*deinit)(struct kvm_vcpu *vcpu);

};

void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run); @@ -69,6 +77,7 @@ const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext( bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx); int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run); void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu); +void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu);

int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu, unsigned long reg_num, unsigned long *reg_val); diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 60d684c76c58..877bcc85c067 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -185,6 +185,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) {

• kvm_riscv_vcpu_sbi_deinit(vcpu);
• /* Cleanup VCPU AIA context */ kvm_riscv_vcpu_aia_deinit(vcpu);

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index d1c83a77735e..3139f171c20f 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -508,5 +508,31 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu) scontext->ext_status[idx] = ext->default_disabled ? KVM_RISCV_SBI_EXT_STATUS_DISABLED : KVM_RISCV_SBI_EXT_STATUS_ENABLED;

• if (ext->init && ext->init(vcpu) != 0)
  

• 	scontext->ext_status[idx] = KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
  

• }

+}

+void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu) +{

• struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
• const struct kvm_riscv_sbi_extension_entry *entry;
• const struct kvm_vcpu_sbi_extension *ext;
• int idx, i;
• for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {

• entry = &sbi_ext[i];
  

• ext = entry->ext_ptr;
  

• idx = entry->ext_idx;
  

• if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status))
  

• 	continue;
  

• if (scontext->ext_status[idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE ||
  

•     !ext->deinit)
  

• 	continue;
  

• ext->deinit(vcpu);
  

  }

}

On 4/24/25 10:31 AM, Clément Léger wrote:

The FWFT SBI extension will need to dynamically allocate memory and do init time specific initialization. Add an init/deinit callbacks that allows to do so.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/kvm_vcpu_sbi.h | 9 +++++++++ arch/riscv/kvm/vcpu.c | 2 ++ arch/riscv/kvm/vcpu_sbi.c | 26 ++++++++++++++++++++++++++ 3 files changed, 37 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index 4ed6203cdd30..bcb90757b149 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -49,6 +49,14 @@ struct kvm_vcpu_sbi_extension { /* Extension specific probe function */ unsigned long (*probe)(struct kvm_vcpu *vcpu);

• /*

• * Init/deinit function called once during VCPU init/destroy. These
  

• * might be use if the SBI extensions need to allocate or do specific
  

• * init time only configuration.
  

• */
  

• int (*init)(struct kvm_vcpu *vcpu);
• void (*deinit)(struct kvm_vcpu *vcpu); };

void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run); @@ -69,6 +77,7 @@ const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext( bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx); int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run); void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu); +void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu); int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu, unsigned long reg_num, unsigned long *reg_val); diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 60d684c76c58..877bcc85c067 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -185,6 +185,8 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) {

• kvm_riscv_vcpu_sbi_deinit(vcpu);
• /* Cleanup VCPU AIA context */ kvm_riscv_vcpu_aia_deinit(vcpu);

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index d1c83a77735e..3139f171c20f 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -508,5 +508,31 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu) scontext->ext_status[idx] = ext->default_disabled ? KVM_RISCV_SBI_EXT_STATUS_DISABLED : KVM_RISCV_SBI_EXT_STATUS_ENABLED;

• if (ext->init && ext->init(vcpu) != 0)
  

• 	scontext->ext_status[idx] = KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
  

• }

+}

+void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu) +{

• struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
• const struct kvm_riscv_sbi_extension_entry *entry;
• const struct kvm_vcpu_sbi_extension *ext;
• int idx, i;
• for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {

• entry = &sbi_ext[i];
  

• ext = entry->ext_ptr;
  

• idx = entry->ext_idx;
  

• if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status))
  

• 	continue;
  

• if (scontext->ext_status[idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE ||
  

•     !ext->deinit)
  

• 	continue;
  

• ext->deinit(vcpu);
  

  } }

LGTM. Reviewed-by: Atish Patra atishp@rivosinc.com

On 4/24/25 10:31 AM, Clément Léger wrote:

Currently, only the STA extension needed a reset function but that's going to be the case for FWFT as well. Add a reset callback that can be implemented by SBI extensions.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/kvm_host.h | 1 - arch/riscv/include/asm/kvm_vcpu_sbi.h | 2 ++ arch/riscv/kvm/vcpu.c | 2 +- arch/riscv/kvm/vcpu_sbi.c | 24 ++++++++++++++++++++++++ arch/riscv/kvm/vcpu_sbi_sta.c | 3 ++- 5 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 0e9c2fab6378..4fa02e082142 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -407,7 +407,6 @@ void __kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu); bool kvm_riscv_vcpu_stopped(struct kvm_vcpu *vcpu); -void kvm_riscv_vcpu_sbi_sta_reset(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu); #endif /* __RISCV_KVM_HOST_H__ */ diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index bcb90757b149..cb68b3a57c8f 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -57,6 +57,7 @@ struct kvm_vcpu_sbi_extension { */ int (*init)(struct kvm_vcpu *vcpu); void (*deinit)(struct kvm_vcpu *vcpu);

• void (*reset)(struct kvm_vcpu *vcpu); };

void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run); @@ -78,6 +79,7 @@ bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx); int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run); void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu); void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu); +void kvm_riscv_vcpu_sbi_reset(struct kvm_vcpu *vcpu); int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu, unsigned long reg_num, unsigned long *reg_val); diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 877bcc85c067..542747e2c7f5 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -94,7 +94,7 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu) vcpu->arch.hfence_tail = 0; memset(vcpu->arch.hfence_queue, 0, sizeof(vcpu->arch.hfence_queue));

• kvm_riscv_vcpu_sbi_sta_reset(vcpu);

• kvm_riscv_vcpu_sbi_reset(vcpu);

/* Reset the guest CSRs for hotplug usecase */ if (loaded) diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 3139f171c20f..50be079b5528 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -536,3 +536,27 @@ void kvm_riscv_vcpu_sbi_deinit(struct kvm_vcpu *vcpu) ext->deinit(vcpu); } }

+void kvm_riscv_vcpu_sbi_reset(struct kvm_vcpu *vcpu) +{

• struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
• const struct kvm_riscv_sbi_extension_entry *entry;
• const struct kvm_vcpu_sbi_extension *ext;
• int idx, i;
• for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {

• entry = &sbi_ext[i];
  

• ext = entry->ext_ptr;
  

• idx = entry->ext_idx;
  

• if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status))
  

• 	continue;
  

• if (scontext->ext_status[idx] != KVM_RISCV_SBI_EXT_STATUS_ENABLED ||
  

•     !ext->reset)
  

• 	continue;
  

• ext->reset(vcpu);
  

• }

+}

diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c index 5f35427114c1..cc6cb7c8f0e4 100644 --- a/arch/riscv/kvm/vcpu_sbi_sta.c +++ b/arch/riscv/kvm/vcpu_sbi_sta.c @@ -16,7 +16,7 @@ #include <asm/sbi.h> #include <asm/uaccess.h> -void kvm_riscv_vcpu_sbi_sta_reset(struct kvm_vcpu *vcpu) +static void kvm_riscv_vcpu_sbi_sta_reset(struct kvm_vcpu *vcpu) { vcpu->arch.sta.shmem = INVALID_GPA; vcpu->arch.sta.last_steal = 0; @@ -156,6 +156,7 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta = { .extid_end = SBI_EXT_STA, .handler = kvm_sbi_ext_sta_handler, .probe = kvm_sbi_ext_sta_probe,

• .reset = kvm_riscv_vcpu_sbi_sta_reset, };

int kvm_riscv_vcpu_get_reg_sbi_sta(struct kvm_vcpu *vcpu,

LGTM. Reviewed-by: Atish Patra atishp@rivosinc.com

On 4/24/25 10:32 AM, Clément Léger wrote:

Add basic infrastructure to support the FWFT extension in KVM.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/include/asm/kvm_host.h | 4 + arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 + arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 29 +++ 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_fwft.c | 216 +++++++++++++++++++++ 7 files changed, 256 insertions(+) create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 4fa02e082142..c3f880763b9a 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -19,6 +19,7 @@ #include <asm/kvm_vcpu_fp.h> #include <asm/kvm_vcpu_insn.h> #include <asm/kvm_vcpu_sbi.h> +#include <asm/kvm_vcpu_sbi_fwft.h> #include <asm/kvm_vcpu_timer.h> #include <asm/kvm_vcpu_pmu.h> @@ -281,6 +282,9 @@ struct kvm_vcpu_arch { /* Performance monitoring context */ struct kvm_pmu pmu_context;

• /* Firmware feature SBI extension context */
• struct kvm_sbi_fwft fwft_context;
• /* 'static' configurations which are set only once */ struct kvm_vcpu_config cfg;

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h index cb68b3a57c8f..ffd03fed0c06 100644 --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h @@ -98,6 +98,7 @@ 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_susp; extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta; +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft; 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/asm/kvm_vcpu_sbi_fwft.h b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h new file mode 100644 index 000000000000..9ba841355758 --- /dev/null +++ b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/*

• • Copyright (c) 2025 Rivos Inc.
• • Authors:

• • Clément Léger <cleger@rivosinc.com>
    

• */

+#ifndef __KVM_VCPU_RISCV_FWFT_H +#define __KVM_VCPU_RISCV_FWFT_H

+#include <asm/sbi.h>

+struct kvm_sbi_fwft_feature;

+struct kvm_sbi_fwft_config {

• const struct kvm_sbi_fwft_feature *feature;
• bool supported;
• unsigned long flags;

+};

+/* FWFT data structure per vcpu */ +struct kvm_sbi_fwft {

• struct kvm_sbi_fwft_config *configs;

+};

+#define vcpu_to_fwft(vcpu) (&(vcpu)->arch.fwft_context)

+#endif /* !__KVM_VCPU_RISCV_FWFT_H */ diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index 5f59fd226cc5..5ba77a3d9f6e 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -204,6 +204,7 @@ enum KVM_RISCV_SBI_EXT_ID { KVM_RISCV_SBI_EXT_DBCN, KVM_RISCV_SBI_EXT_STA, KVM_RISCV_SBI_EXT_SUSP,

• KVM_RISCV_SBI_EXT_FWFT, KVM_RISCV_SBI_EXT_MAX, };

diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile index 4e0bba91d284..06e2d52a9b88 100644 --- a/arch/riscv/kvm/Makefile +++ b/arch/riscv/kvm/Makefile @@ -26,6 +26,7 @@ kvm-y += vcpu_onereg.o kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o kvm-y += vcpu_sbi.o kvm-y += vcpu_sbi_base.o +kvm-y += vcpu_sbi_fwft.o kvm-y += vcpu_sbi_hsm.o kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_sbi_pmu.o kvm-y += vcpu_sbi_replace.o diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 50be079b5528..0748810c0252 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -78,6 +78,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = { .ext_idx = KVM_RISCV_SBI_EXT_STA, .ext_ptr = &vcpu_sbi_ext_sta, },

• {

• .ext_idx = KVM_RISCV_SBI_EXT_FWFT,
  

• .ext_ptr = &vcpu_sbi_ext_fwft,
  

• }, { .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL, .ext_ptr = &vcpu_sbi_ext_experimental,

diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c new file mode 100644 index 000000000000..b0f66c7bf010 --- /dev/null +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0 +/*

• • Copyright (c) 2025 Rivos Inc.
• • Authors:

• • Clément Léger <cleger@rivosinc.com>
    

• */

+#include <linux/errno.h> +#include <linux/err.h> +#include <linux/kvm_host.h> +#include <asm/cpufeature.h> +#include <asm/sbi.h> +#include <asm/kvm_vcpu_sbi.h> +#include <asm/kvm_vcpu_sbi_fwft.h>

+struct kvm_sbi_fwft_feature {

• /**

• * @id: Feature ID
  

• */
  

• enum sbi_fwft_feature_t id;
• /**

• * @supported: Check if the feature is supported on the vcpu
  

• *
  

• * This callback is optional, if not provided the feature is assumed to
  

• * be supported
  

• */
  

• bool (*supported)(struct kvm_vcpu *vcpu);
• /**

• * @set: Set the feature value
  

• *
  

• * Return SBI_SUCCESS on success or an SBI error (SBI_ERR_*)
  

• *
  

• * This callback is mandatory
  

• */
  

• long (*set)(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, unsigned long value);
• /**

• * @get: Get the feature current value
  

• *
  

• * Return SBI_SUCCESS on success or an SBI error (SBI_ERR_*)
  

• *
  

• * This callback is mandatory
  

• */
  

• long (*get)(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, unsigned long *value);

+};

+static const enum sbi_fwft_feature_t kvm_fwft_defined_features[] = {

• SBI_FWFT_MISALIGNED_EXC_DELEG,
• SBI_FWFT_LANDING_PAD,
• SBI_FWFT_SHADOW_STACK,
• SBI_FWFT_DOUBLE_TRAP,
• SBI_FWFT_PTE_AD_HW_UPDATING,
• SBI_FWFT_POINTER_MASKING_PMLEN,

+};

+static bool kvm_fwft_is_defined_feature(enum sbi_fwft_feature_t feature) +{

• int i;
• for (i = 0; i < ARRAY_SIZE(kvm_fwft_defined_features); i++) {

• if (kvm_fwft_defined_features[i] == feature)
  

• 	return true;
  

• }
• return false;

+}

+static const struct kvm_sbi_fwft_feature features[] = { +};

+static struct kvm_sbi_fwft_config * +kvm_sbi_fwft_get_config(struct kvm_vcpu *vcpu, enum sbi_fwft_feature_t feature) +{

• int i;
• struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
• for (i = 0; i < ARRAY_SIZE(features); i++) {

• if (fwft->configs[i].feature->id == feature)
  

• 	return &fwft->configs[i];
  

• }
• return NULL;

+}

+static int kvm_fwft_get_feature(struct kvm_vcpu *vcpu, u32 feature,

• 		struct kvm_sbi_fwft_config **conf)
  

+{

• struct kvm_sbi_fwft_config *tconf;
• tconf = kvm_sbi_fwft_get_config(vcpu, feature);
• if (!tconf) {

• if (kvm_fwft_is_defined_feature(feature))
  

• 	return SBI_ERR_NOT_SUPPORTED;
  

• return SBI_ERR_DENIED;
  

• }
• if (!tconf->supported)

• return SBI_ERR_NOT_SUPPORTED;
  

• *conf = tconf;
• return SBI_SUCCESS;

+}

+static int kvm_sbi_fwft_set(struct kvm_vcpu *vcpu, u32 feature,

• 	    unsigned long value, unsigned long flags)
  

+{

• int ret;
• struct kvm_sbi_fwft_config *conf;
• ret = kvm_fwft_get_feature(vcpu, feature, &conf);
• if (ret)

• return ret;
  

• if ((flags & ~SBI_FWFT_SET_FLAG_LOCK) != 0)

• return SBI_ERR_INVALID_PARAM;
  

• if (conf->flags & SBI_FWFT_SET_FLAG_LOCK)

• return SBI_ERR_DENIED_LOCKED;
  

• conf->flags = flags;
• return conf->feature->set(vcpu, conf, value);

+}

+static int kvm_sbi_fwft_get(struct kvm_vcpu *vcpu, unsigned long feature,

• 	    unsigned long *value)
  

+{

• int ret;
• struct kvm_sbi_fwft_config *conf;
• ret = kvm_fwft_get_feature(vcpu, feature, &conf);
• if (ret)

• return ret;
  

• return conf->feature->get(vcpu, conf, value);

+}

+static int kvm_sbi_ext_fwft_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,

• 		    struct kvm_vcpu_sbi_return *retdata)
  

+{

• int ret;
• struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
• unsigned long funcid = cp->a6;
• switch (funcid) {
• case SBI_EXT_FWFT_SET:

• ret = kvm_sbi_fwft_set(vcpu, cp->a0, cp->a1, cp->a2);
  

• break;
  

• case SBI_EXT_FWFT_GET:

• ret = kvm_sbi_fwft_get(vcpu, cp->a0, &retdata->out_val);
  

• break;
  

• default:

• ret = SBI_ERR_NOT_SUPPORTED;
  

• break;
  

• }
• retdata->err_val = ret;
• return 0;

+}

+static int kvm_sbi_ext_fwft_init(struct kvm_vcpu *vcpu) +{

• struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
• const struct kvm_sbi_fwft_feature *feature;
• struct kvm_sbi_fwft_config *conf;
• int i;
• fwft->configs = kcalloc(ARRAY_SIZE(features), sizeof(struct kvm_sbi_fwft_config),

• 		GFP_KERNEL);
  

• if (!fwft->configs)

• return -ENOMEM;
  

• for (i = 0; i < ARRAY_SIZE(features); i++) {

• feature = &features[i];
  

• conf = &fwft->configs[i];
  

• if (feature->supported)
  

• 	conf->supported = feature->supported(vcpu);
  

• else
  

• 	conf->supported = true;
  

• conf->feature = feature;
  

• }
• return 0;

+}

+static void kvm_sbi_ext_fwft_deinit(struct kvm_vcpu *vcpu) +{

• struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
• kfree(fwft->configs);

+}

+static void kvm_sbi_ext_fwft_reset(struct kvm_vcpu *vcpu) +{

• int i;
• struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
• for (i = 0; i < ARRAY_SIZE(features); i++)

• fwft->configs[i].flags = 0;
  

+}

+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft = {

• .extid_start = SBI_EXT_FWFT,
• .extid_end = SBI_EXT_FWFT,
• .handler = kvm_sbi_ext_fwft_handler,
• .init = kvm_sbi_ext_fwft_init,
• .deinit = kvm_sbi_ext_fwft_deinit,
• .reset = kvm_sbi_ext_fwft_reset,

+};

LGTM. Reviewed-by: Atish Patra atishp@rivosinc.com

On 4/24/25 10:32 AM, Clément Léger wrote:

SBI_FWFT_MISALIGNED_DELEG needs hedeleg to be modified to delegate misaligned load/store exceptions. Save and restore it during CPU load/put.

Signed-off-by: Clément Léger cleger@rivosinc.com Reviewed-by: Deepak Gupta debug@rivosinc.com Reviewed-by: Andrew Jones ajones@ventanamicro.com

---

arch/riscv/kvm/vcpu.c | 3 +++ arch/riscv/kvm/vcpu_sbi_fwft.c | 36 ++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+)

diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 542747e2c7f5..d98e379945c3 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -646,6 +646,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { void *nsh; struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

• struct kvm_vcpu_config *cfg = &vcpu->arch.cfg;

vcpu->cpu = -1; @@ -671,6 +672,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) csr->vstval = nacl_csr_read(nsh, CSR_VSTVAL); csr->hvip = nacl_csr_read(nsh, CSR_HVIP); csr->vsatp = nacl_csr_read(nsh, CSR_VSATP);

• cfg->hedeleg = nacl_csr_read(nsh, CSR_HEDELEG);
  

  } else { csr->vsstatus = csr_read(CSR_VSSTATUS); csr->vsie = csr_read(CSR_VSIE);

@@ -681,6 +683,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) csr->vstval = csr_read(CSR_VSTVAL); csr->hvip = csr_read(CSR_HVIP); csr->vsatp = csr_read(CSR_VSATP);

• cfg->hedeleg = csr_read(CSR_HEDELEG);
  

Can we avoid saving hedeleg in vcpu_put path by updating the cfg->hedeleg in kvm_sbi_fwft_set_misaligned_delegation.

We already update the hedeleg in vcpu_load path from cfg->hedeleg. If the next vcpu did not enable delegation it will get the correct config written to hedeleg.

This will save us a csr read cost in each VM exit path for something that is probably configured once in guest life time.

} } diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c index b0f66c7bf010..d16ee477042f 100644 --- a/arch/riscv/kvm/vcpu_sbi_fwft.c +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c @@ -14,6 +14,8 @@ #include <asm/kvm_vcpu_sbi.h> #include <asm/kvm_vcpu_sbi_fwft.h> +#define MIS_DELEG (BIT_ULL(EXC_LOAD_MISALIGNED) | BIT_ULL(EXC_STORE_MISALIGNED))

• struct kvm_sbi_fwft_feature { /**
  • @id: Feature ID

@@ -68,7 +70,41 @@ static bool kvm_fwft_is_defined_feature(enum sbi_fwft_feature_t feature) return false; } +static bool kvm_sbi_fwft_misaligned_delegation_supported(struct kvm_vcpu *vcpu) +{

• return misaligned_traps_can_delegate();

+}

+static long kvm_sbi_fwft_set_misaligned_delegation(struct kvm_vcpu *vcpu,

• 			struct kvm_sbi_fwft_config *conf,
  

• 			unsigned long value)
  

+{

• if (value == 1)

• csr_set(CSR_HEDELEG, MIS_DELEG);
  

• else if (value == 0)

• csr_clear(CSR_HEDELEG, MIS_DELEG);
  

• else

• return SBI_ERR_INVALID_PARAM;
  

• return SBI_SUCCESS;

+}

+static long kvm_sbi_fwft_get_misaligned_delegation(struct kvm_vcpu *vcpu,

• 			struct kvm_sbi_fwft_config *conf,
  

• 			unsigned long *value)
  

+{

• *value = (csr_read(CSR_HEDELEG) & MIS_DELEG) == MIS_DELEG;
• return SBI_SUCCESS;

+}

• static const struct kvm_sbi_fwft_feature features[] = {
• {

• .id = SBI_FWFT_MISALIGNED_EXC_DELEG,
  

• .supported = kvm_sbi_fwft_misaligned_delegation_supported,
  

• .set = kvm_sbi_fwft_set_misaligned_delegation,
  

• .get = kvm_sbi_fwft_get_misaligned_delegation,
  

• }, };

static struct kvm_sbi_fwft_config *