linux-stable/arch/riscv/kvm/vcpu_sbi.c
Anup Patel ef8949a986 RISC-V: KVM: Forward SBI experimental and vendor extensions
The SBI experimental extension space is for temporary (or experimental)
stuff whereas SBI vendor extension space is for hardware vendor specific
stuff. Both these SBI extension spaces won't be standardized by the SBI
specification so let's blindly forward such SBI calls to the userspace.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-and-tested-by: Atish Patra <atishp@rivosinc.com>
2022-01-06 15:14:33 +05:30

170 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
*
* Authors:
* Atish Patra <atish.patra@wdc.com>
*/
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <asm/sbi.h>
#include <asm/kvm_vcpu_sbi.h>
static int kvm_linux_err_map_sbi(int err)
{
switch (err) {
case 0:
return SBI_SUCCESS;
case -EPERM:
return SBI_ERR_DENIED;
case -EINVAL:
return SBI_ERR_INVALID_PARAM;
case -EFAULT:
return SBI_ERR_INVALID_ADDRESS;
case -EOPNOTSUPP:
return SBI_ERR_NOT_SUPPORTED;
case -EALREADY:
return SBI_ERR_ALREADY_AVAILABLE;
default:
return SBI_ERR_FAILURE;
};
}
#ifdef CONFIG_RISCV_SBI_V01
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01;
#else
static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
.extid_start = -1UL,
.extid_end = -1UL,
.handler = NULL,
};
#endif
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_time;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_ipi;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_rfence;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental;
extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor;
static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
&vcpu_sbi_ext_v01,
&vcpu_sbi_ext_base,
&vcpu_sbi_ext_time,
&vcpu_sbi_ext_ipi,
&vcpu_sbi_ext_rfence,
&vcpu_sbi_ext_hsm,
&vcpu_sbi_ext_experimental,
&vcpu_sbi_ext_vendor,
};
void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
vcpu->arch.sbi_context.return_handled = 0;
vcpu->stat.ecall_exit_stat++;
run->exit_reason = KVM_EXIT_RISCV_SBI;
run->riscv_sbi.extension_id = cp->a7;
run->riscv_sbi.function_id = cp->a6;
run->riscv_sbi.args[0] = cp->a0;
run->riscv_sbi.args[1] = cp->a1;
run->riscv_sbi.args[2] = cp->a2;
run->riscv_sbi.args[3] = cp->a3;
run->riscv_sbi.args[4] = cp->a4;
run->riscv_sbi.args[5] = cp->a5;
run->riscv_sbi.ret[0] = cp->a0;
run->riscv_sbi.ret[1] = cp->a1;
}
int kvm_riscv_vcpu_sbi_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
/* Handle SBI return only once */
if (vcpu->arch.sbi_context.return_handled)
return 0;
vcpu->arch.sbi_context.return_handled = 1;
/* Update return values */
cp->a0 = run->riscv_sbi.ret[0];
cp->a1 = run->riscv_sbi.ret[1];
/* Move to next instruction */
vcpu->arch.guest_context.sepc += 4;
return 0;
}
const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(unsigned long extid)
{
int i = 0;
for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
if (sbi_ext[i]->extid_start <= extid &&
sbi_ext[i]->extid_end >= extid)
return sbi_ext[i];
}
return NULL;
}
int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
int ret = 1;
bool next_sepc = true;
bool userspace_exit = false;
struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
const struct kvm_vcpu_sbi_extension *sbi_ext;
struct kvm_cpu_trap utrap = { 0 };
unsigned long out_val = 0;
bool ext_is_v01 = false;
sbi_ext = kvm_vcpu_sbi_find_ext(cp->a7);
if (sbi_ext && sbi_ext->handler) {
#ifdef CONFIG_RISCV_SBI_V01
if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
ext_is_v01 = true;
#endif
ret = sbi_ext->handler(vcpu, run, &out_val, &utrap, &userspace_exit);
} else {
/* Return error for unsupported SBI calls */
cp->a0 = SBI_ERR_NOT_SUPPORTED;
goto ecall_done;
}
/* Handle special error cases i.e trap, exit or userspace forward */
if (utrap.scause) {
/* No need to increment sepc or exit ioctl loop */
ret = 1;
utrap.sepc = cp->sepc;
kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
next_sepc = false;
goto ecall_done;
}
/* Exit ioctl loop or Propagate the error code the guest */
if (userspace_exit) {
next_sepc = false;
ret = 0;
} else {
/**
* SBI extension handler always returns an Linux error code. Convert
* it to the SBI specific error code that can be propagated the SBI
* caller.
*/
ret = kvm_linux_err_map_sbi(ret);
cp->a0 = ret;
ret = 1;
}
ecall_done:
if (next_sepc)
cp->sepc += 4;
if (!ext_is_v01)
cp->a1 = out_val;
return ret;
}