[PATCH v2 12/15] RISC-V: KVM: add SBI extension init()/deinit() functions

[Clément Léger]

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 <cle...@rivosinc.com>
---
 arch/riscv/include/asm/kvm_vcpu_sbi.h |  9 ++++++++
 arch/riscv/kvm/vcpu.c                 |  2 ++
 arch/riscv/kvm/vcpu_sbi.c             | 30 +++++++++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h 
b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index 4ed6203cdd30..bcb90757b149 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 60d684c76c58..877bcc85c067 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -185,6 +185,8 @@ 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 d1c83a77735e..44f551143498 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -505,8 +505,38 @@ void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
                        continue;
                }
 
+               if (!ext->default_disabled && ext->init &&
+                   ext->init(vcpu) != 0) {
+                           scontext->ext_status[idx] =
+                                   KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
+                           continue;
+               }
+
                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_UNAVAILABLE ||
+                   !ext->deinit)
+                       continue;
+
+               ext->deinit(vcpu);
+       }
+}
-- 
2.47.2