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

[Anup Patel <apatel@xxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxxx>
---
 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