RISC-V: KVM: Add SBI v0.2 base extension

SBI v0.2 base extension defined to allow backward compatibility and
probing of future extensions. This is also the only mandatory SBI
extension that must be implemented by SBI implementors.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>

diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
index 704151969ceb1be6330bf81a46d1ba0a2e633db2..76e4e17a3e00232f8b8c95f886600166485b4cf8 100644 (file)
--- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
+++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
@@ -9,6 +9,8 @@
 #ifndef __RISCV_KVM_VCPU_SBI_H__
 #define __RISCV_KVM_VCPU_SBI_H__
 
+#define KVM_SBI_IMPID 3
+
 #define KVM_SBI_VERSION_MAJOR 0
 #define KVM_SBI_VERSION_MINOR 2
 

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 0d42693cb65e9c50b3a3548f4ec931ae6dc8a66b..9e4c79fd49d74ea2e6411798f93e75ef2a4cde6e 100644 (file)
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -27,6 +27,14 @@ enum sbi_ext_id {
        SBI_EXT_IPI = 0x735049,
        SBI_EXT_RFENCE = 0x52464E43,
        SBI_EXT_HSM = 0x48534D,
+
+       /* Experimentals extensions must lie within this range */
+       SBI_EXT_EXPERIMENTAL_START = 0x08000000,
+       SBI_EXT_EXPERIMENTAL_END = 0x08FFFFFF,
+
+       /* Vendor extensions must lie within this range */
+       SBI_EXT_VENDOR_START = 0x09000000,
+       SBI_EXT_VENDOR_END = 0x09FFFFFF,
 };
 
 enum sbi_ext_base_fid {

diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 892c60b07823da4aa846f236d26c67d023f4d67f..c90b3802ee6d91bff8f2bd1f2cb288d36ea61204 100644 (file)
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -20,4 +20,5 @@ kvm-y += vcpu_fp.o
 kvm-y += vcpu_switch.o
 kvm-y += vcpu_sbi.o
 kvm-$(CONFIG_RISCV_SBI_V01) += vcpu_sbi_v01.o
+kvm-y += vcpu_sbi_base.o
 kvm-y += vcpu_timer.o

diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index a8e0191cd9fcc484d1e5c3844e6f577b32254288..915a044a0b4f8e918027cee8a295ebc8459bebdd 100644 (file)
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -39,9 +39,10 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
        .handler = NULL,
 };
 #endif
-
+extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base;
 static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
        &vcpu_sbi_ext_v01,
+       &vcpu_sbi_ext_base,
 };
 
 void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)

diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
new file mode 100644 (file)
index 0000000..d1ec08f
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_sbi_base.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 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/csr.h>
+#include <asm/sbi.h>
+#include <asm/kvm_vcpu_timer.h>
+#include <asm/kvm_vcpu_sbi.h>
+
+static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
+                                   unsigned long *out_val,
+                                   struct kvm_cpu_trap *trap, bool *exit)
+{
+       int ret = 0;
+       struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+       struct sbiret ecall_ret;
+
+       switch (cp->a6) {
+       case SBI_EXT_BASE_GET_SPEC_VERSION:
+               *out_val = (KVM_SBI_VERSION_MAJOR <<
+                           SBI_SPEC_VERSION_MAJOR_SHIFT) |
+                           KVM_SBI_VERSION_MINOR;
+               break;
+       case SBI_EXT_BASE_GET_IMP_ID:
+               *out_val = KVM_SBI_IMPID;
+               break;
+       case SBI_EXT_BASE_GET_IMP_VERSION:
+               *out_val = 0;
+               break;
+       case SBI_EXT_BASE_PROBE_EXT:
+               if ((cp->a0 >= SBI_EXT_EXPERIMENTAL_START &&
+                    cp->a0 <= SBI_EXT_EXPERIMENTAL_END) ||
+                   (cp->a0 >= SBI_EXT_VENDOR_START &&
+                    cp->a0 <= SBI_EXT_VENDOR_END)) {
+                       /*
+                        * For experimental/vendor extensions
+                        * forward it to the userspace
+                        */
+                       kvm_riscv_vcpu_sbi_forward(vcpu, run);
+                       *exit = true;
+               } else
+                       *out_val = kvm_vcpu_sbi_find_ext(cp->a0) ? 1 : 0;
+               break;
+       case SBI_EXT_BASE_GET_MVENDORID:
+       case SBI_EXT_BASE_GET_MARCHID:
+       case SBI_EXT_BASE_GET_MIMPID:
+               ecall_ret = sbi_ecall(SBI_EXT_BASE, cp->a6, 0, 0, 0, 0, 0, 0);
+               if (!ecall_ret.error)
+                       *out_val = ecall_ret.value;
+               /*TODO: We are unnecessarily converting the error twice */
+               ret = sbi_err_map_linux_errno(ecall_ret.error);
+               break;
+       default:
+               ret = -EOPNOTSUPP;
+               break;
+       }
+
+       return ret;
+}
+
+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_base = {
+       .extid_start = SBI_EXT_BASE,
+       .extid_end = SBI_EXT_BASE,
+       .handler = kvm_sbi_ext_base_handler,
+};