SBI PMU extension allows KVM guests to configure/start/stop/query about
the PMU counters in virtualized enviornment as well.

In order to allow that, KVM implements the entire SBI PMU extension.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 arch/riscv/kvm/Makefile       |  2 +-
 arch/riscv/kvm/vcpu_sbi.c     | 11 +++++
 arch/riscv/kvm/vcpu_sbi_pmu.c | 87 +++++++++++++++++++++++++++++++++++
 3 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/kvm/vcpu_sbi_pmu.c

diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 5de1053..278e97c 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -25,4 +25,4 @@ kvm-y += vcpu_sbi_base.o
 kvm-y += vcpu_sbi_replace.o
 kvm-y += vcpu_sbi_hsm.o
 kvm-y += vcpu_timer.o
-kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o
+kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index fe2897e..15fde15 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -20,6 +20,16 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
 };
 #endif
 
+#ifdef CONFIG_RISCV_PMU_SBI
+extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
+#else
+static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
+	.extid_start = -1UL,
+	.extid_end = -1UL,
+	.handler = NULL,
+};
+#endif
+
 static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
 	&vcpu_sbi_ext_v01,
 	&vcpu_sbi_ext_base,
@@ -28,6 +38,7 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
 	&vcpu_sbi_ext_rfence,
 	&vcpu_sbi_ext_srst,
 	&vcpu_sbi_ext_hsm,
+	&vcpu_sbi_ext_pmu,
 	&vcpu_sbi_ext_experimental,
 	&vcpu_sbi_ext_vendor,
 };
diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c
new file mode 100644
index 0000000..9fdc1e1
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Rivos Inc
+ *
+ * Authors:
+ *     Atish Patra <atishp@rivosinc.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_sbi.h>
+
+static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
+				   struct kvm_vcpu_sbi_return *retdata)
+{
+	int ret = 0;
+	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
+	unsigned long funcid = cp->a6;
+	u64 temp;
+
+	/* Return not supported if PMU is not initialized */
+	if (!kvpmu->init_done) {
+		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
+		return 0;
+	}
+
+	switch (funcid) {
+	case SBI_EXT_PMU_NUM_COUNTERS:
+		ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
+		break;
+	case SBI_EXT_PMU_COUNTER_GET_INFO:
+		ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
+		break;
+	case SBI_EXT_PMU_COUNTER_CFG_MATCH:
+#if defined(CONFIG_32BIT)
+		temp = ((uint64_t)cp->a5 << 32) | cp->a4;
+#else
+		temp = cp->a4;
+#endif
+		/*
+		 * This can fail if perf core framework fails to create an event.
+		 * Forward the error to userspace because it's an error happened
+		 * within the host kernel. The other option would be to convert
+		 * this an SBI error and forward to the guest.
+		 */
+		ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
+						       cp->a2, cp->a3, temp, retdata);
+		break;
+	case SBI_EXT_PMU_COUNTER_START:
+#if defined(CONFIG_32BIT)
+		temp = ((uint64_t)cp->a4 << 32) | cp->a3;
+#else
+		temp = cp->a3;
+#endif
+		ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
+						   temp, retdata);
+		break;
+	case SBI_EXT_PMU_COUNTER_STOP:
+		ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
+		break;
+	case SBI_EXT_PMU_COUNTER_FW_READ:
+		ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata);
+		break;
+	default:
+		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
+	}
+
+	return ret;
+}
+
+static unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
+
+	return kvpmu->init_done;
+}
+
+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
+	.extid_start = SBI_EXT_PMU,
+	.extid_end = SBI_EXT_PMU,
+	.handler = kvm_sbi_ext_pmu_handler,
+	.probe = kvm_sbi_ext_pmu_probe,
+};
-- 
2.25.1

On Sat, Feb 04, 2023 at 05:15:09PM -0800, Atish Patra wrote:
> SBI PMU extension allows KVM guests to configure/start/stop/query about
> the PMU counters in virtualized enviornment as well.
> 
> In order to allow that, KVM implements the entire SBI PMU extension.
> 
> Reviewed-by: Anup Patel <anup@brainfault.org>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
>  arch/riscv/kvm/Makefile       |  2 +-
>  arch/riscv/kvm/vcpu_sbi.c     | 11 +++++
>  arch/riscv/kvm/vcpu_sbi_pmu.c | 87 +++++++++++++++++++++++++++++++++++
>  3 files changed, 99 insertions(+), 1 deletion(-)
>  create mode 100644 arch/riscv/kvm/vcpu_sbi_pmu.c
> 
> diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> index 5de1053..278e97c 100644
> --- a/arch/riscv/kvm/Makefile
> +++ b/arch/riscv/kvm/Makefile
> @@ -25,4 +25,4 @@ kvm-y += vcpu_sbi_base.o
>  kvm-y += vcpu_sbi_replace.o
>  kvm-y += vcpu_sbi_hsm.o
>  kvm-y += vcpu_timer.o
> -kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o
> +kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> index fe2897e..15fde15 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -20,6 +20,16 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
>  };
>  #endif
>  
> +#ifdef CONFIG_RISCV_PMU_SBI
> +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
> +#else
> +static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
> +	.extid_start = -1UL,
> +	.extid_end = -1UL,
> +	.handler = NULL,
> +};
> +#endif
> +
>  static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
>  	&vcpu_sbi_ext_v01,
>  	&vcpu_sbi_ext_base,
> @@ -28,6 +38,7 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
>  	&vcpu_sbi_ext_rfence,
>  	&vcpu_sbi_ext_srst,
>  	&vcpu_sbi_ext_hsm,
> +	&vcpu_sbi_ext_pmu,
>  	&vcpu_sbi_ext_experimental,
>  	&vcpu_sbi_ext_vendor,
>  };
> diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c
> new file mode 100644
> index 0000000..9fdc1e1
> --- /dev/null
> +++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
> @@ -0,0 +1,87 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2023 Rivos Inc
> + *
> + * Authors:
> + *     Atish Patra <atishp@rivosinc.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_sbi.h>
> +
> +static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> +				   struct kvm_vcpu_sbi_return *retdata)
> +{
> +	int ret = 0;
> +	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
> +	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> +	unsigned long funcid = cp->a6;
> +	u64 temp;
> +
> +	/* Return not supported if PMU is not initialized */

This comment isn't necessary, it's just stating what the code
clearly states.

> +	if (!kvpmu->init_done) {
> +		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
> +		return 0;
> +	}
> +
> +	switch (funcid) {
> +	case SBI_EXT_PMU_NUM_COUNTERS:
> +		ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
> +		break;
> +	case SBI_EXT_PMU_COUNTER_GET_INFO:
> +		ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
> +		break;
> +	case SBI_EXT_PMU_COUNTER_CFG_MATCH:
> +#if defined(CONFIG_32BIT)
> +		temp = ((uint64_t)cp->a5 << 32) | cp->a4;
> +#else
> +		temp = cp->a4;
> +#endif
> +		/*
> +		 * This can fail if perf core framework fails to create an event.
> +		 * Forward the error to userspace because it's an error happened
                                                                       ^ which

> +		 * within the host kernel. The other option would be to convert
> +		 * this an SBI error and forward to the guest.
                       ^ to

> +		 */
> +		ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
> +						       cp->a2, cp->a3, temp, retdata);
> +		break;
> +	case SBI_EXT_PMU_COUNTER_START:
> +#if defined(CONFIG_32BIT)
> +		temp = ((uint64_t)cp->a4 << 32) | cp->a3;
> +#else
> +		temp = cp->a3;
> +#endif
> +		ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
> +						   temp, retdata);
> +		break;
> +	case SBI_EXT_PMU_COUNTER_STOP:
> +		ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
> +		break;
> +	case SBI_EXT_PMU_COUNTER_FW_READ:
> +		ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata);
> +		break;
> +	default:
> +		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
> +	}
> +
> +	return ret;
> +}
> +
> +static unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> +
> +	return kvpmu->init_done;
> +}
> +
> +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
> +	.extid_start = SBI_EXT_PMU,
> +	.extid_end = SBI_EXT_PMU,
> +	.handler = kvm_sbi_ext_pmu_handler,
> +	.probe = kvm_sbi_ext_pmu_probe,
> +};
> -- 
> 2.25.1
>

Otherwise,

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

Thanks,
drew

On 5 February 2023 02:15:09 GMT+01:00, Atish Patra <atishp@rivosinc.com> wrote:
>SBI PMU extension allows KVM guests to configure/start/stop/query about
>the PMU counters in virtualized enviornment as well.
>
>In order to allow that, KVM implements the entire SBI PMU extension.
>
>Reviewed-by: Anup Patel <anup@brainfault.org>
>Signed-off-by: Atish Patra <atishp@rivosinc.com>

Hey Atish,
CI is still complaining about something in this patch:
https://gist.github.com/conor-pwbot/8f8d6a60a65b0b44d96c9c3b220e3efd

I'm without a laptop this weekend, so apologies for
the lack of investigation as to whether there's a
reason for it.

Cheers,
Conor.


>---
> arch/riscv/kvm/Makefile       |  2 +-
> arch/riscv/kvm/vcpu_sbi.c     | 11 +++++
> arch/riscv/kvm/vcpu_sbi_pmu.c | 87 +++++++++++++++++++++++++++++++++++
> 3 files changed, 99 insertions(+), 1 deletion(-)
> create mode 100644 arch/riscv/kvm/vcpu_sbi_pmu.c
>
>diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
>index 5de1053..278e97c 100644
>--- a/arch/riscv/kvm/Makefile
>+++ b/arch/riscv/kvm/Makefile
>@@ -25,4 +25,4 @@ kvm-y += vcpu_sbi_base.o
> kvm-y += vcpu_sbi_replace.o
> kvm-y += vcpu_sbi_hsm.o
> kvm-y += vcpu_timer.o
>-kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o
>+kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
>diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
>index fe2897e..15fde15 100644
>--- a/arch/riscv/kvm/vcpu_sbi.c
>+++ b/arch/riscv/kvm/vcpu_sbi.c
>@@ -20,6 +20,16 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
> };
> #endif
> 
>+#ifdef CONFIG_RISCV_PMU_SBI
>+extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
>+#else
>+static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
>+	.extid_start = -1UL,
>+	.extid_end = -1UL,
>+	.handler = NULL,
>+};
>+#endif
>+
> static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
> 	&vcpu_sbi_ext_v01,
> 	&vcpu_sbi_ext_base,
>@@ -28,6 +38,7 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
> 	&vcpu_sbi_ext_rfence,
> 	&vcpu_sbi_ext_srst,
> 	&vcpu_sbi_ext_hsm,
>+	&vcpu_sbi_ext_pmu,
> 	&vcpu_sbi_ext_experimental,
> 	&vcpu_sbi_ext_vendor,
> };
>diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c
>new file mode 100644
>index 0000000..9fdc1e1
>--- /dev/null
>+++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
>@@ -0,0 +1,87 @@
>+// SPDX-License-Identifier: GPL-2.0
>+/*
>+ * Copyright (c) 2023 Rivos Inc
>+ *
>+ * Authors:
>+ *     Atish Patra <atishp@rivosinc.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_sbi.h>
>+
>+static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
>+				   struct kvm_vcpu_sbi_return *retdata)
>+{
>+	int ret = 0;
>+	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
>+	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
>+	unsigned long funcid = cp->a6;
>+	u64 temp;
>+
>+	/* Return not supported if PMU is not initialized */
>+	if (!kvpmu->init_done) {
>+		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
>+		return 0;
>+	}
>+
>+	switch (funcid) {
>+	case SBI_EXT_PMU_NUM_COUNTERS:
>+		ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
>+		break;
>+	case SBI_EXT_PMU_COUNTER_GET_INFO:
>+		ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
>+		break;
>+	case SBI_EXT_PMU_COUNTER_CFG_MATCH:
>+#if defined(CONFIG_32BIT)
>+		temp = ((uint64_t)cp->a5 << 32) | cp->a4;
>+#else
>+		temp = cp->a4;
>+#endif
>+		/*
>+		 * This can fail if perf core framework fails to create an event.
>+		 * Forward the error to userspace because it's an error happened
>+		 * within the host kernel. The other option would be to convert
>+		 * this an SBI error and forward to the guest.
>+		 */
>+		ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
>+						       cp->a2, cp->a3, temp, retdata);
>+		break;
>+	case SBI_EXT_PMU_COUNTER_START:
>+#if defined(CONFIG_32BIT)
>+		temp = ((uint64_t)cp->a4 << 32) | cp->a3;
>+#else
>+		temp = cp->a3;
>+#endif
>+		ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
>+						   temp, retdata);
>+		break;
>+	case SBI_EXT_PMU_COUNTER_STOP:
>+		ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
>+		break;
>+	case SBI_EXT_PMU_COUNTER_FW_READ:
>+		ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata);
>+		break;
>+	default:
>+		retdata->err_val = SBI_ERR_NOT_SUPPORTED;
>+	}
>+
>+	return ret;
>+}
>+
>+static unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
>+{
>+	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
>+
>+	return kvpmu->init_done;
>+}
>+
>+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
>+	.extid_start = SBI_EXT_PMU,
>+	.extid_end = SBI_EXT_PMU,
>+	.handler = kvm_sbi_ext_pmu_handler,
>+	.probe = kvm_sbi_ext_pmu_probe,
>+};

On Sun, Feb 5, 2023 at 2:31 AM Conor Dooley <conor@kernel.org> wrote:
>
>
>
> On 5 February 2023 02:15:09 GMT+01:00, Atish Patra <atishp@rivosinc.com> wrote:
> >SBI PMU extension allows KVM guests to configure/start/stop/query about
> >the PMU counters in virtualized enviornment as well.
> >
> >In order to allow that, KVM implements the entire SBI PMU extension.
> >
> >Reviewed-by: Anup Patel <anup@brainfault.org>
> >Signed-off-by: Atish Patra <atishp@rivosinc.com>
>
> Hey Atish,
> CI is still complaining about something in this patch:
> https://gist.github.com/conor-pwbot/8f8d6a60a65b0b44d96c9c3b220e3efd
>

This is an invalid warning as vcpu_sbi_ext_pmu is used as an extern variable in
arch/riscv/kvm/vcpu_sbi.c. That's how every sbi extension code defines the
kvm_vcpu_sbi_extension in its own respective file.


> I'm without a laptop this weekend, so apologies for
> the lack of investigation as to whether there's a
> reason for it.
>
> Cheers,
> Conor.
>
>
> >---
> > arch/riscv/kvm/Makefile       |  2 +-
> > arch/riscv/kvm/vcpu_sbi.c     | 11 +++++
> > arch/riscv/kvm/vcpu_sbi_pmu.c | 87 +++++++++++++++++++++++++++++++++++
> > 3 files changed, 99 insertions(+), 1 deletion(-)
> > create mode 100644 arch/riscv/kvm/vcpu_sbi_pmu.c
> >was > >diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> >index 5de1053..278e97c 100644
> >--- a/arch/riscv/kvm/Makefile
> >+++ b/arch/riscv/kvm/Makefile
> >@@ -25,4 +25,4 @@ kvm-y += vcpu_sbi_base.o
> > kvm-y += vcpu_sbi_replace.o
> > kvm-y += vcpu_sbi_hsm.o
> > kvm-y += vcpu_timer.o
> >-kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o
> >+kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
> >diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> >index fe2897e..15fde15 100644
> >--- a/arch/riscv/kvm/vcpu_sbi.c
> >+++ b/arch/riscv/kvm/vcpu_sbi.c
> >@@ -20,6 +20,16 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
> > };
> > #endif
> >
> >+#ifdef CONFIG_RISCV_PMU_SBI
> >+extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
> >+#else
> >+static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
> >+      .extid_start = -1UL,
> >+      .extid_end = -1UL,
> >+      .handler = NULL,
> >+};
> >+#endif
> >+
> > static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
> >       &vcpu_sbi_ext_v01
> >       &vcpu_sbi_ext_base,
> >@@ -28,6 +38,7 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
> >       &vcpu_sbi_ext_rfence,
> >       &vcpu_sbi_ext_srst,
> >       &vcpu_sbi_ext_hsm,
> >+      &vcpu_sbi_ext_pmu,
> >       &vcpu_sbi_ext_experimental,
> >       &vcpu_sbi_ext_vendor,
> > };
> >diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c
> >new file mode 100644
> >index 0000000..9fdc1e1
> >--- /dev/null
> >+++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
> >@@ -0,0 +1,87 @@
> >+// SPDX-License-Identifier: GPL-2.0
> >+/*
> >+ * Copyright (c) 2023 Rivos Inc
> >+ *
> >+ * Authors:
> >+ *     Atish Patra <atishp@rivosinc.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_sbi.h>
> >+
> >+static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
> >+                                 struct kvm_vcpu_sbi_return *retdata)
> >+{
> >+      int ret = 0;
> >+      struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
> >+      struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> >+      unsigned long funcid = cp->a6;
> >+      u64 temp;
> >+
> >+      /* Return not supported if PMU is not initialized */
> >+      if (!kvpmu->init_done) {
> >+              retdata->err_val = SBI_ERR_NOT_SUPPORTED;
> >+              return 0;
> >+      }
> >+
> >+      switch (funcid) {
> >+      case SBI_EXT_PMU_NUM_COUNTERS:
> >+              ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
> >+              break;
> >+      case SBI_EXT_PMU_COUNTER_GET_INFO:
> >+              ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
> >+              break;
> >+      case SBI_EXT_PMU_COUNTER_CFG_MATCH:
> >+#if defined(CONFIG_32BIT)
> >+              temp = ((uint64_t)cp->a5 << 32) | cp->a4;
> >+#else
> >+              temp = cp->a4;
> >+#endif
> >+              /*
> >+               * This can fail if perf core framework fails to create an event.
> >+               * Forward the error to userspace because it's an error happened
> >+               * within the host kernel. The other option would be to convert
> >+               * this an SBI error and forward to the guest.
> >+               */
> >+              ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
> >+                                                     cp->a2, cp->a3, temp, retdata);
> >+              break;
> >+      case SBI_EXT_PMU_COUNTER_START:
> >+#if defined(CONFIG_32BIT)
> >+              temp = ((uint64_t)cp->a4 << 32) | cp->a3;
> >+#else
> >+              temp = cp->a3;
> >+#endif
> >+              ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
> >+                                                 temp, retdata);
> >+              break;
> >+      case SBI_EXT_PMU_COUNTER_STOP:
> >+              ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
> >+              break;
> >+      case SBI_EXT_PMU_COUNTER_FW_READ:
> >+              ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata);
> >+              break;
> >+      default:
> >+              retdata->err_val = SBI_ERR_NOT_SUPPORTED;
> >+      }
> >+
> >+      return ret;
> >+}
> >+
> >+static unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
> >+{
> >+      struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
> >+
> >+      return kvpmu->init_done;
> >+}
> >+
> >+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
> >+      .extid_start = SBI_EXT_PMU,
> >+      .extid_end = SBI_EXT_PMU,
> >+      .handler = kvm_sbi_ext_pmu_handler,
> >+      .probe = kvm_sbi_ext_pmu_probe,
> >+};



-- 
Regards,
Atish

On 7 February 2023 06:10:57 GMT, Atish Patra <atishp@atishpatra.org> wrote:
>On Sun, Feb 5, 2023 at 2:31 AM Conor Dooley <conor@kernel.org> wrote:
>>
>>
>>
>> On 5 February 2023 02:15:09 GMT+01:00, Atish Patra <atishp@rivosinc.com> wrote:
>> >SBI PMU extension allows KVM guests to configure/start/stop/query about
>> >the PMU counters in virtualized enviornment as well.
>> >
>> >In order to allow that, KVM implements the entire SBI PMU extension.
>> >
>> >Reviewed-by: Anup Patel <anup@brainfault.org>
>> >Signed-off-by: Atish Patra <atishp@rivosinc.com>
>>
>> Hey Atish,
>> CI is still complaining about something in this patch:
>> https://gist.github.com/conor-pwbot/8f8d6a60a65b0b44d96c9c3b220e3efd
>>
>
>This is an invalid warning as vcpu_sbi_ext_pmu is used as an extern variable in
>arch/riscv/kvm/vcpu_sbi.c. That's how every sbi extension code defines the
>kvm_vcpu_sbi_extension in its own respective file.

Ah, so the user is in another patch.

>> I'm without a laptop this weekend, so apologies for
>> the lack of investigation as to whether there's a
>> reason for it.

Hard to check these things from a phone!
Sorry for bothering you so.

>>
>> Cheers,
>> Conor.
>>
>>
>> >---
>> > arch/riscv/kvm/Makefile       |  2 +-
>> > arch/riscv/kvm/vcpu_sbi.c     | 11 +++++
>> > arch/riscv/kvm/vcpu_sbi_pmu.c | 87 +++++++++++++++++++++++++++++++++++
>> > 3 files changed, 99 insertions(+), 1 deletion(-)
>> > create mode 100644 arch/riscv/kvm/vcpu_sbi_pmu.c
>> >was > >diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
>> >index 5de1053..278e97c 100644
>> >--- a/arch/riscv/kvm/Makefile
>> >+++ b/arch/riscv/kvm/Makefile
>> >@@ -25,4 +25,4 @@ kvm-y += vcpu_sbi_base.o
>> > kvm-y += vcpu_sbi_replace.o
>> > kvm-y += vcpu_sbi_hsm.o
>> > kvm-y += vcpu_timer.o
>> >-kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o
>> >+kvm-$(CONFIG_RISCV_PMU_SBI) += vcpu_pmu.o vcpu_sbi_pmu.o
>> >diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
>> >index fe2897e..15fde15 100644
>> >--- a/arch/riscv/kvm/vcpu_sbi.c
>> >+++ b/arch/riscv/kvm/vcpu_sbi.c
>> >@@ -20,6 +20,16 @@ static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
>> > };
>> > #endif
>> >
>> >+#ifdef CONFIG_RISCV_PMU_SBI
>> >+extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu;
>> >+#else
>> >+static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
>> >+      .extid_start = -1UL,
>> >+      .extid_end = -1UL,
>> >+      .handler = NULL,
>> >+};
>> >+#endif
>> >+
>> > static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
>> >       &vcpu_sbi_ext_v01
>> >       &vcpu_sbi_ext_base,
>> >@@ -28,6 +38,7 @@ static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
>> >       &vcpu_sbi_ext_rfence,
>> >       &vcpu_sbi_ext_srst,
>> >       &vcpu_sbi_ext_hsm,
>> >+      &vcpu_sbi_ext_pmu,
>> >       &vcpu_sbi_ext_experimental,
>> >       &vcpu_sbi_ext_vendor,
>> > };
>> >diff --git a/arch/riscv/kvm/vcpu_sbi_pmu.c b/arch/riscv/kvm/vcpu_sbi_pmu.c
>> >new file mode 100644
>> >index 0000000..9fdc1e1
>> >--- /dev/null
>> >+++ b/arch/riscv/kvm/vcpu_sbi_pmu.c
>> >@@ -0,0 +1,87 @@
>> >+// SPDX-License-Identifier: GPL-2.0
>> >+/*
>> >+ * Copyright (c) 2023 Rivos Inc
>> >+ *
>> >+ * Authors:
>> >+ *     Atish Patra <atishp@rivosinc.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_sbi.h>
>> >+
>> >+static int kvm_sbi_ext_pmu_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
>> >+                                 struct kvm_vcpu_sbi_return *retdata)
>> >+{
>> >+      int ret = 0;
>> >+      struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
>> >+      struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
>> >+      unsigned long funcid = cp->a6;
>> >+      u64 temp;
>> >+
>> >+      /* Return not supported if PMU is not initialized */
>> >+      if (!kvpmu->init_done) {
>> >+              retdata->err_val = SBI_ERR_NOT_SUPPORTED;
>> >+              return 0;
>> >+      }
>> >+
>> >+      switch (funcid) {
>> >+      case SBI_EXT_PMU_NUM_COUNTERS:
>> >+              ret = kvm_riscv_vcpu_pmu_num_ctrs(vcpu, retdata);
>> >+              break;
>> >+      case SBI_EXT_PMU_COUNTER_GET_INFO:
>> >+              ret = kvm_riscv_vcpu_pmu_ctr_info(vcpu, cp->a0, retdata);
>> >+              break;
>> >+      case SBI_EXT_PMU_COUNTER_CFG_MATCH:
>> >+#if defined(CONFIG_32BIT)
>> >+              temp = ((uint64_t)cp->a5 << 32) | cp->a4;
>> >+#else
>> >+              temp = cp->a4;
>> >+#endif
>> >+              /*
>> >+               * This can fail if perf core framework fails to create an event.
>> >+               * Forward the error to userspace because it's an error happened
>> >+               * within the host kernel. The other option would be to convert
>> >+               * this an SBI error and forward to the guest.
>> >+               */
>> >+              ret = kvm_riscv_vcpu_pmu_ctr_cfg_match(vcpu, cp->a0, cp->a1,
>> >+                                                     cp->a2, cp->a3, temp, retdata);
>> >+              break;
>> >+      case SBI_EXT_PMU_COUNTER_START:
>> >+#if defined(CONFIG_32BIT)
>> >+              temp = ((uint64_t)cp->a4 << 32) | cp->a3;
>> >+#else
>> >+              temp = cp->a3;
>> >+#endif
>> >+              ret = kvm_riscv_vcpu_pmu_ctr_start(vcpu, cp->a0, cp->a1, cp->a2,
>> >+                                                 temp, retdata);
>> >+              break;
>> >+      case SBI_EXT_PMU_COUNTER_STOP:
>> >+              ret = kvm_riscv_vcpu_pmu_ctr_stop(vcpu, cp->a0, cp->a1, cp->a2, retdata);
>> >+              break;
>> >+      case SBI_EXT_PMU_COUNTER_FW_READ:
>> >+              ret = kvm_riscv_vcpu_pmu_ctr_read(vcpu, cp->a0, retdata);
>> >+              break;
>> >+      default:
>> >+              retdata->err_val = SBI_ERR_NOT_SUPPORTED;
>> >+      }
>> >+
>> >+      return ret;
>> >+}
>> >+
>> >+static unsigned long kvm_sbi_ext_pmu_probe(struct kvm_vcpu *vcpu)
>> >+{
>> >+      struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
>> >+
>> >+      return kvpmu->init_done;
>> >+}
>> >+
>> >+const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
>> >+      .extid_start = SBI_EXT_PMU,
>> >+      .extid_end = SBI_EXT_PMU,
>> >+      .handler = kvm_sbi_ext_pmu_handler,
>> >+      .probe = kvm_sbi_ext_pmu_probe,
>> >+};
>
>
>