[PATCH 7/9] RISC-V: KVM: Save mvendorid, marchid, and mimpid when creating VCPU

Anup Patel
2022-11-28T16:15:28Z

We should save VCPU mvendorid, marchid, and mimpid at the time
of creating VCPU so that we don't have to do host SBI call every
time Guest/VM ask for these details.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/include/asm/kvm_host.h | 5 +++++
arch/riscv/kvm/vcpu.c | 6 ++++++
arch/riscv/kvm/vcpu_sbi_base.c | 11 +++++------
3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 91c74b09a970..93f43a3e7886 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -165,6 +165,11 @@ struct kvm_vcpu_arch {
/* ISA feature bits (similar to MISA) */
DECLARE_BITMAP(isa, RISCV_ISA_EXT_MAX);

+ /* Vendor, Arch, and Implementation details */
+ unsigned long mvendorid;
+ unsigned long marchid;
+ unsigned long mimpid;
+
/* SSCRATCH, STVEC, and SCOUNTEREN of Host */
unsigned long host_sscratch;
unsigned long host_stvec;
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 68c86f632d37..312a8a926867 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -21,6 +21,7 @@
#include <asm/csr.h>
#include <asm/cacheflush.h>
#include <asm/hwcap.h>
+#include <asm/sbi.h>

const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
KVM_GENERIC_VCPU_STATS(),
@@ -171,6 +172,11 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
set_bit(host_isa, vcpu->arch.isa);
}

+ /* Setup vendor, arch, and implementation details */
+ vcpu->arch.mvendorid = sbi_get_mvendorid();
+ vcpu->arch.marchid = sbi_get_marchid();
+ vcpu->arch.mimpid = sbi_get_mimpid();
+
/* Setup VCPU hfence queue */
spin_lock_init(&vcpu->arch.hfence_lock);

diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
index 0c806f61c629..5d65c634d301 100644
--- a/arch/riscv/kvm/vcpu_sbi_base.c
+++ b/arch/riscv/kvm/vcpu_sbi_base.c
@@ -19,7 +19,6 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
{
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:
@@ -48,13 +47,13 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
*out_val = kvm_vcpu_sbi_find_ext(cp->a0) ? 1 : 0;
break;
case SBI_EXT_BASE_GET_MVENDORID:
+ *out_val = vcpu->arch.mvendorid;
+ break;
case SBI_EXT_BASE_GET_MARCHID:
+ *out_val = vcpu->arch.marchid;
+ break;
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);
+ *out_val = vcpu->arch.mimpid;
break;
default:
ret = -EOPNOTSUPP;
--
2.34.1