Re: [PATCH 2/6] RISC-V: KVM: Introduce feature specific reset for SBI FWFT

On Thu, Aug 14, 2025 at 09:25:44PM +0530, Anup Patel wrote:

The SBI FWFT feature values must be reset upon VCPU reset so introduce feature specific reset callback for this purpose.

Signed-off-by: Anup Patel apatel@ventanamicro.com

arch/riscv/kvm/vcpu_sbi_fwft.c | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c index 164a01288b0a..5a3bad0f9330 100644 --- a/arch/riscv/kvm/vcpu_sbi_fwft.c +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c @@ -30,6 +30,13 @@ struct kvm_sbi_fwft_feature { */ bool (*supported)(struct kvm_vcpu *vcpu);

• /**

• * @reset: Reset the feature value irrespective whether feature is supported or not
  

• *
  

• * This callback is mandatory
  

• */
  

• void (*reset)(struct kvm_vcpu *vcpu);
• /**
  • @set: Set the feature value

@@ -75,6 +82,13 @@ static bool kvm_sbi_fwft_misaligned_delegation_supported(struct kvm_vcpu *vcpu) return misaligned_traps_can_delegate(); } +static void kvm_sbi_fwft_reset_misaligned_delegation(struct kvm_vcpu *vcpu) +{

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

+}

static long kvm_sbi_fwft_set_misaligned_delegation(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, unsigned long value) @@ -124,6 +138,11 @@ static bool kvm_sbi_fwft_pointer_masking_pmlen_supported(struct kvm_vcpu *vcpu) return fwft->have_vs_pmlen_7 || fwft->have_vs_pmlen_16; } +static void kvm_sbi_fwft_reset_pointer_masking_pmlen(struct kvm_vcpu *vcpu) +{

• vcpu->arch.cfg.henvcfg &= ~ENVCFG_PMM;

+}

static long kvm_sbi_fwft_set_pointer_masking_pmlen(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, unsigned long value) @@ -180,6 +199,7 @@ static const struct kvm_sbi_fwft_feature features[] = { { .id = SBI_FWFT_MISALIGNED_EXC_DELEG, .supported = kvm_sbi_fwft_misaligned_delegation_supported,

• .reset = kvm_sbi_fwft_reset_misaligned_delegation,
  

  .set = kvm_sbi_fwft_set_misaligned_delegation, .get = kvm_sbi_fwft_get_misaligned_delegation, },

@@ -187,6 +207,7 @@ static const struct kvm_sbi_fwft_feature features[] = { { .id = SBI_FWFT_POINTER_MASKING_PMLEN, .supported = kvm_sbi_fwft_pointer_masking_pmlen_supported,

• .reset = kvm_sbi_fwft_reset_pointer_masking_pmlen,
  

  .set = kvm_sbi_fwft_set_pointer_masking_pmlen, .get = kvm_sbi_fwft_get_pointer_masking_pmlen, },

@@ -321,11 +342,16 @@ static void kvm_sbi_ext_fwft_deinit(struct kvm_vcpu *vcpu) static void kvm_sbi_ext_fwft_reset(struct kvm_vcpu *vcpu) {

• int i; struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);

• const struct kvm_sbi_fwft_feature *feature;
• int i;

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

• for (i = 0; i < ARRAY_SIZE(features); i++) { fwft->configs[i].flags = 0;

• feature = &features[i];
  

• if (feature->reset)
  

• 	feature->reset(vcpu);
  

• }

} const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft = { -- 2.43.0

Reviewed-by: Andrew Jones ajones@ventanamicro.com