RISC-V: KVM: add SBI extension init()/deinit() functions

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>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20250523101932.1594077-12-cleger@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index 439ab2b3534f8ed1f5e0578b96e51ecda140fb58..8ee54f729b3b313179d6fae90081ed9e4402ede0 100644 (file)
--- 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);
@@ -72,6 +80,7 @@ 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 0462863206ca7e1b976094b2826ed89b1bf87413..549f14df8af8c47593f785a8bb261c7aaa550a9d 100644 (file)
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -187,6 +187,8 @@ 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 6e09b518a5d1a8515a4a3511bf7cfc93634d6d78..2737f42e720c5ff5ecccf929e9279a21636bae57 100644 (file)
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -536,5 +536,31 @@ 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);
        }
 }