This patch implements VCPU create, init and destroy functions
required by generic KVM module. We don't have much dynamic
resources in struct kvm_vcpu_arch so thest functions are quite
simple for KVM RISC-V.

Signed-off-by: Anup Patel <anup.pa...@wdc.com>
---
 arch/riscv/include/asm/kvm_host.h | 70 ++++++++++++++++++++++++++
 arch/riscv/kvm/vcpu.c             | 83 +++++++++++++++++++++++++++++--
 2 files changed, 149 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h 
b/arch/riscv/include/asm/kvm_host.h
index 81acfb307d5c..244eabe62710 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -54,7 +54,77 @@ struct kvm_arch {
        phys_addr_t pgd_phys;
 };
 
+struct kvm_cpu_context {
+       unsigned long zero;
+       unsigned long ra;
+       unsigned long sp;
+       unsigned long gp;
+       unsigned long tp;
+       unsigned long t0;
+       unsigned long t1;
+       unsigned long t2;
+       unsigned long s0;
+       unsigned long s1;
+       unsigned long a0;
+       unsigned long a1;
+       unsigned long a2;
+       unsigned long a3;
+       unsigned long a4;
+       unsigned long a5;
+       unsigned long a6;
+       unsigned long a7;
+       unsigned long s2;
+       unsigned long s3;
+       unsigned long s4;
+       unsigned long s5;
+       unsigned long s6;
+       unsigned long s7;
+       unsigned long s8;
+       unsigned long s9;
+       unsigned long s10;
+       unsigned long s11;
+       unsigned long t3;
+       unsigned long t4;
+       unsigned long t5;
+       unsigned long t6;
+       unsigned long sepc;
+       unsigned long sstatus;
+       unsigned long hstatus;
+};
+
+struct kvm_vcpu_csr {
+       unsigned long hedeleg;
+       unsigned long hideleg;
+       unsigned long vsstatus;
+       unsigned long vsie;
+       unsigned long vstvec;
+       unsigned long vsscratch;
+       unsigned long vsepc;
+       unsigned long vscause;
+       unsigned long vstval;
+       unsigned long vsip;
+       unsigned long vsatp;
+};
+
 struct kvm_vcpu_arch {
+       /* VCPU ran atleast once */
+       bool ran_atleast_once;
+
+       /* ISA feature bits (similar to MISA) */
+       unsigned long isa;
+
+       /* CPU context of Guest VCPU */
+       struct kvm_cpu_context guest_context;
+
+       /* CPU CSR context of Guest VCPU */
+       struct kvm_vcpu_csr guest_csr;
+
+       /* CPU context upon Guest VCPU reset */
+       struct kvm_cpu_context guest_reset_context;
+
+       /* CPU CSR context upon Guest VCPU reset */
+       struct kvm_vcpu_csr guest_reset_csr;
+
        /* Don't run the VCPU (blocked) */
        bool pause;
 };
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 9fea9128d964..1ae806f28c0e 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -31,10 +31,48 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
        { NULL }
 };
 
+#define KVM_RISCV_ISA_ALLOWED  (RISCV_ISA_EXT_A | \
+                                RISCV_ISA_EXT_C | \
+                                RISCV_ISA_EXT_D | \
+                                RISCV_ISA_EXT_F | \
+                                RISCV_ISA_EXT_I | \
+                                RISCV_ISA_EXT_M | \
+                                RISCV_ISA_EXT_S | \
+                                RISCV_ISA_EXT_U)
+
+static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
+{
+       struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+       struct kvm_vcpu_csr *reset_csr = &vcpu->arch.guest_reset_csr;
+       struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+       struct kvm_cpu_context *reset_cntx = &vcpu->arch.guest_reset_context;
+
+       memcpy(csr, reset_csr, sizeof(*csr));
+
+       memcpy(cntx, reset_cntx, sizeof(*cntx));
+}
+
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 {
-       /* TODO: */
-       return NULL;
+       int err;
+       struct kvm_vcpu *vcpu;
+
+       vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+       if (!vcpu) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       err = kvm_vcpu_init(vcpu, kvm, id);
+       if (err)
+               goto free_vcpu;
+
+       return vcpu;
+
+free_vcpu:
+       kmem_cache_free(kvm_vcpu_cache, vcpu);
+out:
+       return ERR_PTR(err);
 }
 
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
@@ -48,13 +86,47 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 
 int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 {
-       /* TODO: */
+       struct kvm_cpu_context *cntx;
+       struct kvm_vcpu_csr *csr;
+
+       /* Mark this VCPU never ran */
+       vcpu->arch.ran_atleast_once = false;
+
+       /* Setup ISA features available to VCPU */
+       vcpu->arch.isa = riscv_isa & KVM_RISCV_ISA_ALLOWED;
+
+       /* Setup reset state of shadow SSTATUS and HSTATUS CSRs */
+       cntx = &vcpu->arch.guest_reset_context;
+       cntx->sstatus = SR_SPP | SR_SPIE;
+       cntx->hstatus = 0;
+       cntx->hstatus |= HSTATUS_SP2V;
+       cntx->hstatus |= HSTATUS_SP2P;
+       cntx->hstatus |= HSTATUS_SPV;
+
+       /* Setup reset state of HEDELEG and HIDELEG CSRs */
+       csr = &vcpu->arch.guest_reset_csr;
+       csr->hedeleg = 0;
+       csr->hedeleg |= (1UL << EXC_INST_MISALIGNED);
+       csr->hedeleg |= (1UL << EXC_BREAKPOINT);
+       csr->hedeleg |= (1UL << EXC_SYSCALL);
+       csr->hedeleg |= (1UL << EXC_INST_PAGE_FAULT);
+       csr->hedeleg |= (1UL << EXC_LOAD_PAGE_FAULT);
+       csr->hedeleg |= (1UL << EXC_STORE_PAGE_FAULT);
+       csr->hideleg = 0;
+       csr->hideleg |= SIE_SSIE;
+       csr->hideleg |= SIE_STIE;
+       csr->hideleg |= SIE_SEIE;
+
+       /* Reset VCPU */
+       kvm_riscv_reset_vcpu(vcpu);
+
        return 0;
 }
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
-       /* TODO: */
+       kvm_riscv_stage2_flush_cache(vcpu);
+       kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
@@ -207,6 +279,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct 
kvm_run *run)
        int ret;
        unsigned long scause, stval;
 
+       /* Mark this VCPU ran atleast once */
+       vcpu->arch.ran_atleast_once = true;
+
        /* Process MMIO value returned from user-space */
        if (run->exit_reason == KVM_EXIT_MMIO) {
                ret = kvm_riscv_vcpu_mmio_return(vcpu, vcpu->run);
-- 
2.17.1

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