RISC-V: KVM: Introduce feature specific reset for SBI FWFT

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>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Link: https://lore.kernel.org/r/20250823155947.1354229-3-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>

diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c
index 93bcc8fb45d66634dc6355f011d4d2891a105f06..252899f074827e1587addf07a482eba17fa1467e 100644 (file)
--- 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)
@@ -189,6 +208,7 @@ 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,
        },
@@ -196,6 +216,7 @@ 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,
        },
@@ -330,11 +351,16 @@ 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 = {