1. Patchew
  2. linux
  3. [PATCH 0/6] riscv: add SBI FWFT misaligned exception delegation support
  4. View patch

[PATCH 3/6] RISC-V: KVM: add SBI extension init()/deinit() functions

Clément Léger posted 6 patches 1 year, 1 month ago
There is a newer version of this series
[PATCH 3/6] RISC-V: KVM: add SBI extension init()/deinit() functions
Posted by Clément Léger 1 year, 1 month ago 
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>
---
 arch/riscv/include/asm/kvm_vcpu_sbi.h |  9 ++++++++
 arch/riscv/kvm/vcpu.c                 |  2 ++
 arch/riscv/kvm/vcpu_sbi.c             | 31 ++++++++++++++++++++++++++-
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index b96705258cf9..8c465ce90e73 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 e048dcc6e65e..3420a4a62c94 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -180,6 +180,8 @@ 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 6e704ed86a83..d2dbb0762072 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -486,7 +486,7 @@ void kvm_riscv_vcpu_sbi_init(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;
+	int idx, i, ret;
 
 	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
 		entry = &sbi_ext[i];
@@ -501,8 +501,37 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
 			continue;
 		}
 
+		if (ext->init) {
+			ret = ext->init(vcpu);
+			if (ret)
+				scontext->ext_status[idx] =
+					KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
+		}
+
 		scontext->ext_status[idx] = ext->default_disabled ?
 					KVM_RISCV_SBI_EXT_STATUS_DISABLED :
 					KVM_RISCV_SBI_EXT_STATUS_ENABLED;
 	}
 }
+
+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_ENABLED || !ext->deinit)
+			continue;
+
+		ext->deinit(vcpu);
+	}
+}
-- 
2.47.1
Re: [PATCH 3/6] RISC-V: KVM: add SBI extension init()/deinit() functions
Posted by Samuel Holland 1 year ago 
Hi Clément,

On 2025-01-06 9:48 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>
> ---
>  arch/riscv/include/asm/kvm_vcpu_sbi.h |  9 ++++++++
>  arch/riscv/kvm/vcpu.c                 |  2 ++
>  arch/riscv/kvm/vcpu_sbi.c             | 31 ++++++++++++++++++++++++++-
>  3 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> index b96705258cf9..8c465ce90e73 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 e048dcc6e65e..3420a4a62c94 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -180,6 +180,8 @@ 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 6e704ed86a83..d2dbb0762072 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -486,7 +486,7 @@ void kvm_riscv_vcpu_sbi_init(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;
> +	int idx, i, ret;
>  
>  	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
>  		entry = &sbi_ext[i];
> @@ -501,8 +501,37 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
>  			continue;
>  		}
>  
> +		if (ext->init) {
> +			ret = ext->init(vcpu);
> +			if (ret)
> +				scontext->ext_status[idx] =
> +					KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
> +		}
> +
>  		scontext->ext_status[idx] = ext->default_disabled ?
>  					KVM_RISCV_SBI_EXT_STATUS_DISABLED :
>  					KVM_RISCV_SBI_EXT_STATUS_ENABLED;

This will overwrite the KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE set above.

>  	}
>  }
> +
> +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_ENABLED || !ext->deinit)

Given that an extension can be enabled/disabled after initialization, this
should only skip deinit if the status is UNAVAILABLE.

Regards,
Samuel

> +			continue;
> +
> +		ext->deinit(vcpu);
> +	}
> +}
Re: [PATCH 3/6] RISC-V: KVM: add SBI extension init()/deinit() functions
Posted by Clément Léger 1 year ago 

On 11/01/2025 00:42, Samuel Holland wrote:
> Hi Clément,
> 
> On 2025-01-06 9:48 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>
>> ---
>>  arch/riscv/include/asm/kvm_vcpu_sbi.h |  9 ++++++++
>>  arch/riscv/kvm/vcpu.c                 |  2 ++
>>  arch/riscv/kvm/vcpu_sbi.c             | 31 ++++++++++++++++++++++++++-
>>  3 files changed, 41 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
>> index b96705258cf9..8c465ce90e73 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 e048dcc6e65e..3420a4a62c94 100644
>> --- a/arch/riscv/kvm/vcpu.c
>> +++ b/arch/riscv/kvm/vcpu.c
>> @@ -180,6 +180,8 @@ 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 6e704ed86a83..d2dbb0762072 100644
>> --- a/arch/riscv/kvm/vcpu_sbi.c
>> +++ b/arch/riscv/kvm/vcpu_sbi.c
>> @@ -486,7 +486,7 @@ void kvm_riscv_vcpu_sbi_init(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;
>> +	int idx, i, ret;
>>  
>>  	for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
>>  		entry = &sbi_ext[i];
>> @@ -501,8 +501,37 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
>>  			continue;
>>  		}
>>  
>> +		if (ext->init) {
>> +			ret = ext->init(vcpu);
>> +			if (ret)
>> +				scontext->ext_status[idx] =
>> +					KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
>> +		}
>> +
>>  		scontext->ext_status[idx] = ext->default_disabled ?
>>  					KVM_RISCV_SBI_EXT_STATUS_DISABLED :
>>  					KVM_RISCV_SBI_EXT_STATUS_ENABLED;
> 
> This will overwrite the KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE set above.

Oh yes indeed, I should add a "continue" under the if above.

> 
>>  	}
>>  }
>> +
>> +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_ENABLED || !ext->deinit)
> 
> Given that an extension can be enabled/disabled after initialization, this
> should only skip deinit if the status is UNAVAILABLE.

yeah, make sense as well,

Thanks for the review,

Clément

> 
> Regards,
> Samuel
> 
>> +			continue;
>> +
>> +		ext->deinit(vcpu);
>> +	}
>> +}
>

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.