[PATCH v5 1/5] RISC-V: KVM: Mark the existing SBI implementation as v01
Atish Patra
atishp at rivosinc.com
Thu Nov 18 00:39:08 PST 2021
From: Atish Patra <atish.patra at wdc.com>
The existing SBI specification impelementation follows v0.1
specification. The latest specification allows more
scalability and performance improvements.
Rename the existing implementation as v01 and provide a way to allow
future extensions.
Reviewed-by: Anup Patel <anup.patel at wdc.com>
Signed-off-by: Atish Patra <atish.patra at wdc.com>
Signed-off-by: Atish Patra <atishp at rivosinc.com>
---
arch/riscv/include/asm/kvm_vcpu_sbi.h | 29 +++++
arch/riscv/kvm/vcpu_sbi.c | 149 ++++++++++++++++++++------
2 files changed, 145 insertions(+), 33 deletions(-)
create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi.h
diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
new file mode 100644
index 000000000000..1a4cb0db2d0b
--- /dev/null
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/**
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ * Atish Patra <atish.patra at wdc.com>
+ */
+
+#ifndef __RISCV_KVM_VCPU_SBI_H__
+#define __RISCV_KVM_VCPU_SBI_H__
+
+#define KVM_SBI_VERSION_MAJOR 0
+#define KVM_SBI_VERSION_MINOR 2
+
+struct kvm_vcpu_sbi_extension {
+ unsigned long extid_start;
+ unsigned long extid_end;
+ /**
+ * SBI extension handler. It can be defined for a given extension or group of
+ * extension. But it should always return linux error codes rather than SBI
+ * specific error codes.
+ */
+ int (*handler)(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ unsigned long *out_val, struct kvm_cpu_trap *utrap,
+ bool *exit);
+};
+
+const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(unsigned long extid);
+#endif /* __RISCV_KVM_VCPU_SBI_H__ */
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index eb3c045edf11..32376906ff20 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -1,5 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
-/**
+/*
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
*
* Authors:
@@ -12,9 +12,25 @@
#include <asm/csr.h>
#include <asm/sbi.h>
#include <asm/kvm_vcpu_timer.h>
+#include <asm/kvm_vcpu_sbi.h>
-#define SBI_VERSION_MAJOR 0
-#define SBI_VERSION_MINOR 1
+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;
+ default:
+ return SBI_ERR_FAILURE;
+ };
+}
static void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu,
struct kvm_run *run)
@@ -72,21 +88,19 @@ static void kvm_sbi_system_shutdown(struct kvm_vcpu *vcpu,
run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}
-int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_sbi_ext_v01_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ unsigned long *out_val,
+ struct kvm_cpu_trap *utrap,
+ bool *exit)
{
ulong hmask;
- int i, ret = 1;
+ int i, ret = 0;
u64 next_cycle;
struct kvm_vcpu *rvcpu;
- bool next_sepc = true;
struct cpumask cm, hm;
struct kvm *kvm = vcpu->kvm;
- struct kvm_cpu_trap utrap = { 0 };
struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
- if (!cp)
- return -EINVAL;
-
switch (cp->a7) {
case SBI_EXT_0_1_CONSOLE_GETCHAR:
case SBI_EXT_0_1_CONSOLE_PUTCHAR:
@@ -95,8 +109,7 @@ int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
* handled in kernel so we forward these to user-space
*/
kvm_riscv_vcpu_sbi_forward(vcpu, run);
- next_sepc = false;
- ret = 0;
+ *exit = true;
break;
case SBI_EXT_0_1_SET_TIMER:
#if __riscv_xlen == 32
@@ -104,47 +117,42 @@ int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
#else
next_cycle = (u64)cp->a0;
#endif
- kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
+ ret = kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
break;
case SBI_EXT_0_1_CLEAR_IPI:
- kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_SOFT);
+ ret = kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_SOFT);
break;
case SBI_EXT_0_1_SEND_IPI:
if (cp->a0)
hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
- &utrap);
+ utrap);
else
hmask = (1UL << atomic_read(&kvm->online_vcpus)) - 1;
- if (utrap.scause) {
- utrap.sepc = cp->sepc;
- kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
- next_sepc = false;
+ if (utrap->scause)
break;
- }
+
for_each_set_bit(i, &hmask, BITS_PER_LONG) {
rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
- kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_VS_SOFT);
+ ret = kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_VS_SOFT);
+ if (ret < 0)
+ break;
}
break;
case SBI_EXT_0_1_SHUTDOWN:
kvm_sbi_system_shutdown(vcpu, run, KVM_SYSTEM_EVENT_SHUTDOWN);
- next_sepc = false;
- ret = 0;
+ *exit = true;
break;
case SBI_EXT_0_1_REMOTE_FENCE_I:
case SBI_EXT_0_1_REMOTE_SFENCE_VMA:
case SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID:
if (cp->a0)
hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
- &utrap);
+ utrap);
else
hmask = (1UL << atomic_read(&kvm->online_vcpus)) - 1;
- if (utrap.scause) {
- utrap.sepc = cp->sepc;
- kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
- next_sepc = false;
+ if (utrap->scause)
break;
- }
+
cpumask_clear(&cm);
for_each_set_bit(i, &hmask, BITS_PER_LONG) {
rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
@@ -154,22 +162,97 @@ int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
}
riscv_cpuid_to_hartid_mask(&cm, &hm);
if (cp->a7 == SBI_EXT_0_1_REMOTE_FENCE_I)
- sbi_remote_fence_i(cpumask_bits(&hm));
+ ret = sbi_remote_fence_i(cpumask_bits(&hm));
else if (cp->a7 == SBI_EXT_0_1_REMOTE_SFENCE_VMA)
- sbi_remote_hfence_vvma(cpumask_bits(&hm),
+ ret = sbi_remote_hfence_vvma(cpumask_bits(&hm),
cp->a1, cp->a2);
else
- sbi_remote_hfence_vvma_asid(cpumask_bits(&hm),
+ ret = sbi_remote_hfence_vvma_asid(cpumask_bits(&hm),
cp->a1, cp->a2, cp->a3);
break;
default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
+ .extid_start = SBI_EXT_0_1_SET_TIMER,
+ .extid_end = SBI_EXT_0_1_SHUTDOWN,
+ .handler = kvm_sbi_ext_v01_handler,
+};
+
+static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
+ &vcpu_sbi_ext_v01,
+};
+
+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) {
+ if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
+ cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
+ ext_is_v01 = true;
+ ret = sbi_ext->handler(vcpu, run, &out_val, &utrap, &userspace_exit);
+ } else {
/* Return error for unsupported SBI calls */
cp->a0 = SBI_ERR_NOT_SUPPORTED;
- break;
+ 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;
}
--
2.33.1
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