diff options
Diffstat (limited to 'arch/riscv/kvm/vcpu_exit.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_exit.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c new file mode 100644 index 000000000000..2415722c01b8 --- /dev/null +++ b/arch/riscv/kvm/vcpu_exit.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Anup Patel <anup.patel@wdc.com> + */ + +#include <linux/kvm_host.h> +#include <asm/csr.h> +#include <asm/insn-def.h> + +static int gstage_page_fault(struct kvm_vcpu *vcpu, struct kvm_run *run, + struct kvm_cpu_trap *trap) +{ + struct kvm_memory_slot *memslot; + unsigned long hva, fault_addr; + bool writable; + gfn_t gfn; + int ret; + + fault_addr = (trap->htval << 2) | (trap->stval & 0x3); + gfn = fault_addr >> PAGE_SHIFT; + memslot = gfn_to_memslot(vcpu->kvm, gfn); + hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable); + + if (kvm_is_error_hva(hva) || + (trap->scause == EXC_STORE_GUEST_PAGE_FAULT && !writable)) { + switch (trap->scause) { + case EXC_LOAD_GUEST_PAGE_FAULT: + return kvm_riscv_vcpu_mmio_load(vcpu, run, + fault_addr, + trap->htinst); + case EXC_STORE_GUEST_PAGE_FAULT: + return kvm_riscv_vcpu_mmio_store(vcpu, run, + fault_addr, + trap->htinst); + default: + return -EOPNOTSUPP; + }; + } + + ret = kvm_riscv_gstage_map(vcpu, memslot, fault_addr, hva, + (trap->scause == EXC_STORE_GUEST_PAGE_FAULT) ? true : false); + if (ret < 0) + return ret; + + return 1; +} + +/** + * kvm_riscv_vcpu_unpriv_read -- Read machine word from Guest memory + * + * @vcpu: The VCPU pointer + * @read_insn: Flag representing whether we are reading instruction + * @guest_addr: Guest address to read + * @trap: Output pointer to trap details + */ +unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu, + bool read_insn, + unsigned long guest_addr, + struct kvm_cpu_trap *trap) +{ + register unsigned long taddr asm("a0") = (unsigned long)trap; + register unsigned long ttmp asm("a1"); + unsigned long flags, val, tmp, old_stvec, old_hstatus; + + local_irq_save(flags); + + old_hstatus = csr_swap(CSR_HSTATUS, vcpu->arch.guest_context.hstatus); + old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap); + + if (read_insn) { + /* + * HLVX.HU instruction + * 0110010 00011 rs1 100 rd 1110011 + */ + asm volatile ("\n" + ".option push\n" + ".option norvc\n" + "add %[ttmp], %[taddr], 0\n" + HLVX_HU(%[val], %[addr]) + "andi %[tmp], %[val], 3\n" + "addi %[tmp], %[tmp], -3\n" + "bne %[tmp], zero, 2f\n" + "addi %[addr], %[addr], 2\n" + HLVX_HU(%[tmp], %[addr]) + "sll %[tmp], %[tmp], 16\n" + "add %[val], %[val], %[tmp]\n" + "2:\n" + ".option pop" + : [val] "=&r" (val), [tmp] "=&r" (tmp), + [taddr] "+&r" (taddr), [ttmp] "+&r" (ttmp), + [addr] "+&r" (guest_addr) : : "memory"); + + if (trap->scause == EXC_LOAD_PAGE_FAULT) + trap->scause = EXC_INST_PAGE_FAULT; + } else { + /* + * HLV.D instruction + * 0110110 00000 rs1 100 rd 1110011 + * + * HLV.W instruction + * 0110100 00000 rs1 100 rd 1110011 + */ + asm volatile ("\n" + ".option push\n" + ".option norvc\n" + "add %[ttmp], %[taddr], 0\n" +#ifdef CONFIG_64BIT + HLV_D(%[val], %[addr]) +#else + HLV_W(%[val], %[addr]) +#endif + ".option pop" + : [val] "=&r" (val), + [taddr] "+&r" (taddr), [ttmp] "+&r" (ttmp) + : [addr] "r" (guest_addr) : "memory"); + } + + csr_write(CSR_STVEC, old_stvec); + csr_write(CSR_HSTATUS, old_hstatus); + + local_irq_restore(flags); + + return val; +} + +/** + * kvm_riscv_vcpu_trap_redirect -- Redirect trap to Guest + * + * @vcpu: The VCPU pointer + * @trap: Trap details + */ +void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu, + struct kvm_cpu_trap *trap) +{ + unsigned long vsstatus = csr_read(CSR_VSSTATUS); + + /* Change Guest SSTATUS.SPP bit */ + vsstatus &= ~SR_SPP; + if (vcpu->arch.guest_context.sstatus & SR_SPP) + vsstatus |= SR_SPP; + + /* Change Guest SSTATUS.SPIE bit */ + vsstatus &= ~SR_SPIE; + if (vsstatus & SR_SIE) + vsstatus |= SR_SPIE; + + /* Clear Guest SSTATUS.SIE bit */ + vsstatus &= ~SR_SIE; + + /* Update Guest SSTATUS */ + csr_write(CSR_VSSTATUS, vsstatus); + + /* Update Guest SCAUSE, STVAL, and SEPC */ + csr_write(CSR_VSCAUSE, trap->scause); + csr_write(CSR_VSTVAL, trap->stval); + csr_write(CSR_VSEPC, trap->sepc); + + /* Set Guest PC to Guest exception vector */ + vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC); + + /* Set Guest privilege mode to supervisor */ + vcpu->arch.guest_context.sstatus |= SR_SPP; +} + +/* + * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on + * proper exit to userspace. + */ +int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, + struct kvm_cpu_trap *trap) +{ + int ret; + + /* If we got host interrupt then do nothing */ + if (trap->scause & CAUSE_IRQ_FLAG) + return 1; + + /* Handle guest traps */ + ret = -EFAULT; + run->exit_reason = KVM_EXIT_UNKNOWN; + switch (trap->scause) { + case EXC_INST_ILLEGAL: + case EXC_LOAD_MISALIGNED: + case EXC_STORE_MISALIGNED: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) { + kvm_riscv_vcpu_trap_redirect(vcpu, trap); + ret = 1; + } + break; + case EXC_VIRTUAL_INST_FAULT: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) + ret = kvm_riscv_vcpu_virtual_insn(vcpu, run, trap); + break; + case EXC_INST_GUEST_PAGE_FAULT: + case EXC_LOAD_GUEST_PAGE_FAULT: + case EXC_STORE_GUEST_PAGE_FAULT: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) + ret = gstage_page_fault(vcpu, run, trap); + break; + case EXC_SUPERVISOR_SYSCALL: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) + ret = kvm_riscv_vcpu_sbi_ecall(vcpu, run); + break; + default: + break; + } + + /* Print details in-case of error */ + if (ret < 0) { + kvm_err("VCPU exit error %d\n", ret); + kvm_err("SEPC=0x%lx SSTATUS=0x%lx HSTATUS=0x%lx\n", + vcpu->arch.guest_context.sepc, + vcpu->arch.guest_context.sstatus, + vcpu->arch.guest_context.hstatus); + kvm_err("SCAUSE=0x%lx STVAL=0x%lx HTVAL=0x%lx HTINST=0x%lx\n", + trap->scause, trap->stval, trap->htval, trap->htinst); + } + + return ret; +} |