2022-11-28 16:20:09

by Anup Patel

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

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 <[email protected]>
---
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

2022-11-28 21:28:50

by Atish Patra

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

On Mon, Nov 28, 2022 at 8:15 AM Anup Patel <[email protected]> wrote:
>
> 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 <[email protected]>
> ---
> 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
>

Reviewed-by: Atish Patra <[email protected]>

--
Regards,
Atish

2022-11-29 05:55:29

by Andrew Jones

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

On Mon, Nov 28, 2022 at 09:44:22PM +0530, Anup Patel wrote:
> 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 <[email protected]>
> ---
> 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(-)
>

Reviewed-by: Andrew Jones <[email protected]>