SBI MPXY support for KVM Guest

[PATCH 1/4] RISC-V: KVM: Convert kvm_riscv_vcpu_sbi_forward() into extension handler

Posted by Anup Patel 3 months, 3 weeks ago

All uses of kvm_riscv_vcpu_sbi_forward() also updates retdata->uexit so
to further reduce code duplication move retdata->uexit assignment to
kvm_riscv_vcpu_sbi_forward() and convert it into SBI extension handler.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 arch/riscv/include/asm/kvm_vcpu_sbi.h |  4 +++-
 arch/riscv/kvm/vcpu_sbi.c             |  6 +++++-
 arch/riscv/kvm/vcpu_sbi_base.c        | 20 +++-----------------
 arch/riscv/kvm/vcpu_sbi_replace.c     | 27 +--------------------------
 arch/riscv/kvm/vcpu_sbi_system.c      |  4 +---
 arch/riscv/kvm/vcpu_sbi_v01.c         |  3 +--
 6 files changed, 14 insertions(+), 50 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index 3497489e04db..446f4a8eb3cd 100644
--- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -69,7 +69,9 @@ struct kvm_vcpu_sbi_extension {
 			     unsigned long reg_size, const void *reg_val);
 };
 
-void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_riscv_vcpu_sbi_forward_handler(struct kvm_vcpu *vcpu,
+				       struct kvm_run *run,
+				       struct kvm_vcpu_sbi_return *retdata);
 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
 				     struct kvm_run *run,
 				     u32 type, u64 flags);
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index 1b13623380e1..fd4106c276d8 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -120,7 +120,9 @@ static bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx)
 	return sext && scontext->ext_status[sext->ext_idx] != KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
 }
 
-void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
+int kvm_riscv_vcpu_sbi_forward_handler(struct kvm_vcpu *vcpu,
+				       struct kvm_run *run,
+				       struct kvm_vcpu_sbi_return *retdata)
 {
 	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 
@@ -137,6 +139,8 @@ void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	run->riscv_sbi.args[5] = cp->a5;
 	run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;
 	run->riscv_sbi.ret[1] = 0;
+	retdata->uexit = true;
+	return 0;
 }
 
 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
index 5bc570b984f4..ca489f2dfbdf 100644
--- a/arch/riscv/kvm/vcpu_sbi_base.c
+++ b/arch/riscv/kvm/vcpu_sbi_base.c
@@ -41,8 +41,7 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			 * For experimental/vendor extensions
 			 * forward it to the userspace
 			 */
-			kvm_riscv_vcpu_sbi_forward(vcpu, run);
-			retdata->uexit = true;
+			return kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
 		} else {
 			sbi_ext = kvm_vcpu_sbi_find_ext(vcpu, cp->a0);
 			*out_val = sbi_ext && sbi_ext->probe ?
@@ -72,27 +71,14 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
 	.handler = kvm_sbi_ext_base_handler,
 };
 
-static int kvm_sbi_ext_forward_handler(struct kvm_vcpu *vcpu,
-				       struct kvm_run *run,
-				       struct kvm_vcpu_sbi_return *retdata)
-{
-	/*
-	 * Both SBI experimental and vendor extensions are
-	 * unconditionally forwarded to userspace.
-	 */
-	kvm_riscv_vcpu_sbi_forward(vcpu, run);
-	retdata->uexit = true;
-	return 0;
-}
-
 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental = {
 	.extid_start = SBI_EXT_EXPERIMENTAL_START,
 	.extid_end = SBI_EXT_EXPERIMENTAL_END,
-	.handler = kvm_sbi_ext_forward_handler,
+	.handler = kvm_riscv_vcpu_sbi_forward_handler,
 };
 
 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor = {
 	.extid_start = SBI_EXT_VENDOR_START,
 	.extid_end = SBI_EXT_VENDOR_END,
-	.handler = kvm_sbi_ext_forward_handler,
+	.handler = kvm_riscv_vcpu_sbi_forward_handler,
 };
diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c
index b490ed1428a6..2c456e26f6ca 100644
--- a/arch/riscv/kvm/vcpu_sbi_replace.c
+++ b/arch/riscv/kvm/vcpu_sbi_replace.c
@@ -186,34 +186,9 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst = {
 	.handler = kvm_sbi_ext_srst_handler,
 };
 
-static int kvm_sbi_ext_dbcn_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;
-
-	switch (funcid) {
-	case SBI_EXT_DBCN_CONSOLE_WRITE:
-	case SBI_EXT_DBCN_CONSOLE_READ:
-	case SBI_EXT_DBCN_CONSOLE_WRITE_BYTE:
-		/*
-		 * The SBI debug console functions are unconditionally
-		 * forwarded to the userspace.
-		 */
-		kvm_riscv_vcpu_sbi_forward(vcpu, run);
-		retdata->uexit = true;
-		break;
-	default:
-		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
-	}
-
-	return 0;
-}
-
 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn = {
 	.extid_start = SBI_EXT_DBCN,
 	.extid_end = SBI_EXT_DBCN,
 	.default_disabled = true,
-	.handler = kvm_sbi_ext_dbcn_handler,
+	.handler = kvm_riscv_vcpu_sbi_forward_handler,
 };
diff --git a/arch/riscv/kvm/vcpu_sbi_system.c b/arch/riscv/kvm/vcpu_sbi_system.c
index 359be90b0fc5..c6f7e609ac79 100644
--- a/arch/riscv/kvm/vcpu_sbi_system.c
+++ b/arch/riscv/kvm/vcpu_sbi_system.c
@@ -47,9 +47,7 @@ static int kvm_sbi_ext_susp_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		kvm_riscv_vcpu_sbi_request_reset(vcpu, cp->a1, cp->a2);
 
 		/* userspace provides the suspend implementation */
-		kvm_riscv_vcpu_sbi_forward(vcpu, run);
-		retdata->uexit = true;
-		break;
+		return kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
 	default:
 		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
 		break;
diff --git a/arch/riscv/kvm/vcpu_sbi_v01.c b/arch/riscv/kvm/vcpu_sbi_v01.c
index 368dfddd23d9..188d5ea5b3b8 100644
--- a/arch/riscv/kvm/vcpu_sbi_v01.c
+++ b/arch/riscv/kvm/vcpu_sbi_v01.c
@@ -32,8 +32,7 @@ static int kvm_sbi_ext_v01_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		 * The CONSOLE_GETCHAR/CONSOLE_PUTCHAR SBI calls cannot be
 		 * handled in kernel so we forward these to user-space
 		 */
-		kvm_riscv_vcpu_sbi_forward(vcpu, run);
-		retdata->uexit = true;
+		ret = kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
 		break;
 	case SBI_EXT_0_1_SET_TIMER:
 #if __riscv_xlen == 32
-- 
2.43.0

Re: [PATCH 1/4] RISC-V: KVM: Convert kvm_riscv_vcpu_sbi_forward() into extension handler

Posted by Andrew Jones 3 months, 3 weeks ago

On Fri, Oct 17, 2025 at 09:29:22PM +0530, Anup Patel wrote:
> All uses of kvm_riscv_vcpu_sbi_forward() also updates retdata->uexit so
> to further reduce code duplication move retdata->uexit assignment to
> kvm_riscv_vcpu_sbi_forward() and convert it into SBI extension handler.
> 
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
>  arch/riscv/include/asm/kvm_vcpu_sbi.h |  4 +++-
>  arch/riscv/kvm/vcpu_sbi.c             |  6 +++++-
>  arch/riscv/kvm/vcpu_sbi_base.c        | 20 +++-----------------
>  arch/riscv/kvm/vcpu_sbi_replace.c     | 27 +--------------------------
>  arch/riscv/kvm/vcpu_sbi_system.c      |  4 +---
>  arch/riscv/kvm/vcpu_sbi_v01.c         |  3 +--
>  6 files changed, 14 insertions(+), 50 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> index 3497489e04db..446f4a8eb3cd 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> @@ -69,7 +69,9 @@ struct kvm_vcpu_sbi_extension {
>  			     unsigned long reg_size, const void *reg_val);
>  };
>  
> -void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run);
> +int kvm_riscv_vcpu_sbi_forward_handler(struct kvm_vcpu *vcpu,
> +				       struct kvm_run *run,
> +				       struct kvm_vcpu_sbi_return *retdata);
>  void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
>  				     struct kvm_run *run,
>  				     u32 type, u64 flags);
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> index 1b13623380e1..fd4106c276d8 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -120,7 +120,9 @@ static bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx)
>  	return sext && scontext->ext_status[sext->ext_idx] != KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
>  }
>  
> -void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
> +int kvm_riscv_vcpu_sbi_forward_handler(struct kvm_vcpu *vcpu,
> +				       struct kvm_run *run,
> +				       struct kvm_vcpu_sbi_return *retdata)
>  {
>  	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
>  
> @@ -137,6 +139,8 @@ void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  	run->riscv_sbi.args[5] = cp->a5;
>  	run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;
>  	run->riscv_sbi.ret[1] = 0;
> +	retdata->uexit = true;
> +	return 0;
>  }
>  
>  void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
> diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
> index 5bc570b984f4..ca489f2dfbdf 100644
> --- a/arch/riscv/kvm/vcpu_sbi_base.c
> +++ b/arch/riscv/kvm/vcpu_sbi_base.c
> @@ -41,8 +41,7 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
>  			 * For experimental/vendor extensions
>  			 * forward it to the userspace
>  			 */
> -			kvm_riscv_vcpu_sbi_forward(vcpu, run);
> -			retdata->uexit = true;
> +			return kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
>  		} else {
>  			sbi_ext = kvm_vcpu_sbi_find_ext(vcpu, cp->a0);
>  			*out_val = sbi_ext && sbi_ext->probe ?
> @@ -72,27 +71,14 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
>  	.handler = kvm_sbi_ext_base_handler,
>  };
>  
> -static int kvm_sbi_ext_forward_handler(struct kvm_vcpu *vcpu,
> -				       struct kvm_run *run,
> -				       struct kvm_vcpu_sbi_return *retdata)
> -{
> -	/*
> -	 * Both SBI experimental and vendor extensions are
> -	 * unconditionally forwarded to userspace.
> -	 */
> -	kvm_riscv_vcpu_sbi_forward(vcpu, run);
> -	retdata->uexit = true;
> -	return 0;
> -}
> -
>  const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental = {
>  	.extid_start = SBI_EXT_EXPERIMENTAL_START,
>  	.extid_end = SBI_EXT_EXPERIMENTAL_END,
> -	.handler = kvm_sbi_ext_forward_handler,
> +	.handler = kvm_riscv_vcpu_sbi_forward_handler,
>  };
>  
>  const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor = {
>  	.extid_start = SBI_EXT_VENDOR_START,
>  	.extid_end = SBI_EXT_VENDOR_END,
> -	.handler = kvm_sbi_ext_forward_handler,
> +	.handler = kvm_riscv_vcpu_sbi_forward_handler,
>  };
> diff --git a/arch/riscv/kvm/vcpu_sbi_replace.c b/arch/riscv/kvm/vcpu_sbi_replace.c
> index b490ed1428a6..2c456e26f6ca 100644
> --- a/arch/riscv/kvm/vcpu_sbi_replace.c
> +++ b/arch/riscv/kvm/vcpu_sbi_replace.c
> @@ -186,34 +186,9 @@ const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst = {
>  	.handler = kvm_sbi_ext_srst_handler,
>  };
>  
> -static int kvm_sbi_ext_dbcn_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;
> -
> -	switch (funcid) {
> -	case SBI_EXT_DBCN_CONSOLE_WRITE:
> -	case SBI_EXT_DBCN_CONSOLE_READ:
> -	case SBI_EXT_DBCN_CONSOLE_WRITE_BYTE:
> -		/*
> -		 * The SBI debug console functions are unconditionally
> -		 * forwarded to the userspace.
> -		 */
> -		kvm_riscv_vcpu_sbi_forward(vcpu, run);
> -		retdata->uexit = true;
> -		break;
> -	default:
> -		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
> -	}
> -
> -	return 0;
> -}
> -
>  const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn = {
>  	.extid_start = SBI_EXT_DBCN,
>  	.extid_end = SBI_EXT_DBCN,
>  	.default_disabled = true,
> -	.handler = kvm_sbi_ext_dbcn_handler,
> +	.handler = kvm_riscv_vcpu_sbi_forward_handler,
>  };
> diff --git a/arch/riscv/kvm/vcpu_sbi_system.c b/arch/riscv/kvm/vcpu_sbi_system.c
> index 359be90b0fc5..c6f7e609ac79 100644
> --- a/arch/riscv/kvm/vcpu_sbi_system.c
> +++ b/arch/riscv/kvm/vcpu_sbi_system.c
> @@ -47,9 +47,7 @@ static int kvm_sbi_ext_susp_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
>  		kvm_riscv_vcpu_sbi_request_reset(vcpu, cp->a1, cp->a2);
>  
>  		/* userspace provides the suspend implementation */
> -		kvm_riscv_vcpu_sbi_forward(vcpu, run);
> -		retdata->uexit = true;
> -		break;
> +		return kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
>  	default:
>  		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
>  		break;
> diff --git a/arch/riscv/kvm/vcpu_sbi_v01.c b/arch/riscv/kvm/vcpu_sbi_v01.c
> index 368dfddd23d9..188d5ea5b3b8 100644
> --- a/arch/riscv/kvm/vcpu_sbi_v01.c
> +++ b/arch/riscv/kvm/vcpu_sbi_v01.c
> @@ -32,8 +32,7 @@ static int kvm_sbi_ext_v01_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
>  		 * The CONSOLE_GETCHAR/CONSOLE_PUTCHAR SBI calls cannot be
>  		 * handled in kernel so we forward these to user-space
>  		 */
> -		kvm_riscv_vcpu_sbi_forward(vcpu, run);
> -		retdata->uexit = true;
> +		ret = kvm_riscv_vcpu_sbi_forward_handler(vcpu, run, retdata);
>  		break;
>  	case SBI_EXT_0_1_SET_TIMER:
>  #if __riscv_xlen == 32
> -- 
> 2.43.0
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

[PATCH 1/4] RISC-V: KVM: Convert kvm_riscv_vcpu_sbi_forward() into extension handler
[PATCH 2/4] RISC-V: KVM: Add separate source for forwarded SBI extensions
[PATCH 3/4] RISC-V: KVM: Add SBI MPXY extension support for Guest
[PATCH 4/4] KVM: riscv: selftests: Add SBI MPXY extension to get-reg-list