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Message-ID: <65f1b520-5d0d-4494-b3f5-1d3e3265a762@sifive.com>
Date: Fri, 10 Jan 2025 17:47:43 -0600
From: Samuel Holland <samuel.holland@...ive.com>
To: Clément Léger <cleger@...osinc.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>, Anup Patel <anup@...infault.org>,
Atish Patra <atishp@...shpatra.org>, linux-riscv@...ts.infradead.org,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
kvm-riscv@...ts.infradead.org
Subject: Re: [PATCH 4/6] RISC-V: KVM: add support for FWFT SBI extension
Hi Clément,
This looks good to me, but will need changes for the updated semantics of the
LOCK flag. One minor comment below.
On 2025-01-06 9:48 AM, Clément Léger wrote:
> Add basic infrastructure to support the FWFT extension in KVM.
>
> Signed-off-by: Clément Léger <cleger@...osinc.com>
> ---
> arch/riscv/include/asm/kvm_host.h | 4 +
> arch/riscv/include/asm/kvm_vcpu_sbi.h | 1 +
> arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 37 +++++
> arch/riscv/include/uapi/asm/kvm.h | 1 +
> arch/riscv/kvm/Makefile | 1 +
> arch/riscv/kvm/vcpu_sbi.c | 4 +
> arch/riscv/kvm/vcpu_sbi_fwft.c | 176 +++++++++++++++++++++
> 7 files changed, 224 insertions(+)
> create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
> create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c
>
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 35eab6e0f4ae..9bd046ed7907 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -19,6 +19,7 @@
> #include <asm/kvm_vcpu_fp.h>
> #include <asm/kvm_vcpu_insn.h>
> #include <asm/kvm_vcpu_sbi.h>
> +#include <asm/kvm_vcpu_sbi_fwft.h>
> #include <asm/kvm_vcpu_timer.h>
> #include <asm/kvm_vcpu_pmu.h>
>
> @@ -276,6 +277,9 @@ struct kvm_vcpu_arch {
> /* Performance monitoring context */
> struct kvm_pmu pmu_context;
>
> + /* Firmware feature SBI extension context */
> + struct kvm_sbi_fwft fwft_context;
> +
> /* 'static' configurations which are set only once */
> struct kvm_vcpu_config cfg;
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> index 8c465ce90e73..7ff200a1ad3b 100644
> --- a/arch/riscv/include/asm/kvm_vcpu_sbi.h
> +++ b/arch/riscv/include/asm/kvm_vcpu_sbi.h
> @@ -95,6 +95,7 @@ extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_srst;
> extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm;
> extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_dbcn;
> extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_sta;
> +extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft;
> extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_experimental;
> extern const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_vendor;
>
> diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
> new file mode 100644
> index 000000000000..5782517f6e08
> --- /dev/null
> +++ b/arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2025 Rivos Inc.
> + *
> + * Authors:
> + * Clément Léger <cleger@...osinc.com>
> + */
> +
> +#ifndef __KVM_VCPU_RISCV_FWFT_H
> +#define __KVM_VCPU_RISCV_FWFT_H
> +
> +#include <asm/sbi.h>
> +
> +struct kvm_sbi_fwft_config;
> +struct kvm_vcpu;
> +
> +struct kvm_sbi_fwft_feature {
> + enum sbi_fwft_feature_t id;
> + bool (*supported)(struct kvm_vcpu *vcpu);
> + int (*set)(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, unsigned long value);
> + int (*get)(struct kvm_vcpu *vcpu, struct kvm_sbi_fwft_config *conf, unsigned long *value);
> +};
> +
> +struct kvm_sbi_fwft_config {
> + const struct kvm_sbi_fwft_feature *feature;
> + bool supported;
> + unsigned long flags;
> +};
> +
> +/* FWFT data structure per vcpu */
> +struct kvm_sbi_fwft {
> + struct kvm_sbi_fwft_config *configs;
> +};
> +
> +#define vcpu_to_fwft(vcpu) (&(vcpu)->arch.fwft_context)
> +
> +#endif /* !__KVM_VCPU_RISCV_FWFT_H */
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 3482c9a73d1b..0813145a6272 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -198,6 +198,7 @@ enum KVM_RISCV_SBI_EXT_ID {
> KVM_RISCV_SBI_EXT_VENDOR,
> KVM_RISCV_SBI_EXT_DBCN,
> KVM_RISCV_SBI_EXT_STA,
> + KVM_RISCV_SBI_EXT_FWFT,
> KVM_RISCV_SBI_EXT_MAX,
> };
>
> diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> index 0fb1840c3e0a..ece6b119913a 100644
> --- a/arch/riscv/kvm/Makefile
> +++ b/arch/riscv/kvm/Makefile
> @@ -32,6 +32,7 @@ kvm-y += vcpu_sbi_replace.o
> kvm-y += vcpu_sbi_sta.o
> kvm-$(CONFIG_RISCV_SBI_V01) += vcpu_sbi_v01.o
> kvm-y += vcpu_switch.o
> +kvm-y += vcpu_sbi_fwft.o
nit: this should go with the other vcpu_sbi_* files.
Regards,
Samuel
> kvm-y += vcpu_timer.o
> kvm-y += vcpu_vector.o
> kvm-y += vm.o
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> index d2dbb0762072..5bf6c92cca5b 100644
> --- a/arch/riscv/kvm/vcpu_sbi.c
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -74,6 +74,10 @@ static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = {
> .ext_idx = KVM_RISCV_SBI_EXT_STA,
> .ext_ptr = &vcpu_sbi_ext_sta,
> },
> + {
> + .ext_idx = KVM_RISCV_SBI_EXT_FWFT,
> + .ext_ptr = &vcpu_sbi_ext_fwft,
> + },
> {
> .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL,
> .ext_ptr = &vcpu_sbi_ext_experimental,
> diff --git a/arch/riscv/kvm/vcpu_sbi_fwft.c b/arch/riscv/kvm/vcpu_sbi_fwft.c
> new file mode 100644
> index 000000000000..55433e805baa
> --- /dev/null
> +++ b/arch/riscv/kvm/vcpu_sbi_fwft.c
> @@ -0,0 +1,176 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2025 Rivos Inc.
> + *
> + * Authors:
> + * Clément Léger <cleger@...osinc.com>
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/err.h>
> +#include <linux/kvm_host.h>
> +#include <asm/cpufeature.h>
> +#include <asm/sbi.h>
> +#include <asm/kvm_vcpu_sbi.h>
> +#include <asm/kvm_vcpu_sbi_fwft.h>
> +
> +static const enum sbi_fwft_feature_t kvm_fwft_defined_features[] = {
> + SBI_FWFT_MISALIGNED_EXC_DELEG,
> + SBI_FWFT_LANDING_PAD,
> + SBI_FWFT_SHADOW_STACK,
> + SBI_FWFT_DOUBLE_TRAP,
> + SBI_FWFT_PTE_AD_HW_UPDATING,
> + SBI_FWFT_POINTER_MASKING_PMLEN,
> +};
> +
> +static bool kvm_fwft_is_defined_feature(enum sbi_fwft_feature_t feature)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(kvm_fwft_defined_features); i++) {
> + if (kvm_fwft_defined_features[i] == feature)
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static const struct kvm_sbi_fwft_feature features[] = {
> +};
> +
> +static struct kvm_sbi_fwft_config *
> +kvm_sbi_fwft_get_config(struct kvm_vcpu *vcpu, enum sbi_fwft_feature_t feature)
> +{
> + int i = 0;
> + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
> +
> + for (i = 0; i < ARRAY_SIZE(features); i++) {
> + if (fwft->configs[i].feature->id == feature)
> + return &fwft->configs[i];
> + }
> +
> + return NULL;
> +}
> +
> +static int kvm_fwft_get_feature(struct kvm_vcpu *vcpu,
> + enum sbi_fwft_feature_t feature,
> + struct kvm_sbi_fwft_config **conf)
> +{
> + struct kvm_sbi_fwft_config *tconf;
> +
> + tconf = kvm_sbi_fwft_get_config(vcpu, feature);
> + if (!tconf) {
> + if (kvm_fwft_is_defined_feature(feature))
> + return SBI_ERR_NOT_SUPPORTED;
> +
> + return SBI_ERR_DENIED;
> + }
> +
> + if (!tconf->supported)
> + return SBI_ERR_NOT_SUPPORTED;
> +
> + *conf = tconf;
> +
> + return SBI_SUCCESS;
> +}
> +
> +static int kvm_sbi_fwft_set(struct kvm_vcpu *vcpu,
> + enum sbi_fwft_feature_t feature,
> + unsigned long value, unsigned long flags)
> +{
> + int ret;
> + struct kvm_sbi_fwft_config *conf;
> +
> + ret = kvm_fwft_get_feature(vcpu, feature, &conf);
> + if (ret)
> + return ret;
> +
> + if ((flags & ~SBI_FWFT_SET_FLAG_LOCK) != 0)
> + return SBI_ERR_INVALID_PARAM;
> +
> + if (conf->flags & SBI_FWFT_SET_FLAG_LOCK)
> + return SBI_ERR_DENIED;
> +
> + conf->flags = flags;
> +
> + return conf->feature->set(vcpu, conf, value);
> +}
> +
> +static int kvm_sbi_fwft_get(struct kvm_vcpu *vcpu,
> + enum sbi_fwft_feature_t feature,
> + unsigned long *value)
> +{
> + int ret;
> + struct kvm_sbi_fwft_config *conf;
> +
> + ret = kvm_fwft_get_feature(vcpu, feature, &conf);
> + if (ret)
> + return ret;
> +
> + return conf->feature->get(vcpu, conf, value);
> +}
> +
> +static int kvm_sbi_ext_fwft_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;
> + unsigned long funcid = cp->a6;
> +
> + switch (funcid) {
> + case SBI_EXT_FWFT_SET:
> + ret = kvm_sbi_fwft_set(vcpu, cp->a0, cp->a1, cp->a2);
> + break;
> + case SBI_EXT_FWFT_GET:
> + ret = kvm_sbi_fwft_get(vcpu, cp->a0, &retdata->out_val);
> + break;
> + default:
> + ret = SBI_ERR_NOT_SUPPORTED;
> + break;
> + }
> +
> + retdata->err_val = ret;
> +
> + return 0;
> +}
> +
> +static int kvm_sbi_ext_fwft_init(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
> + const struct kvm_sbi_fwft_feature *feature;
> + struct kvm_sbi_fwft_config *conf;
> + int i;
> +
> + fwft->configs = kcalloc(ARRAY_SIZE(features), sizeof(struct kvm_sbi_fwft_config),
> + GFP_KERNEL);
> + if (!fwft->configs)
> + return -ENOMEM;
> +
> + for (i = 0; i < ARRAY_SIZE(features); i++) {
> + feature = &features[i];
> + conf = &fwft->configs[i];
> + if (feature->supported)
> + conf->supported = feature->supported(vcpu);
> + else
> + conf->supported = true;
> +
> + conf->feature = feature;
> + }
> +
> + return 0;
> +}
> +
> +static void kvm_sbi_ext_fwft_deinit(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_sbi_fwft *fwft = vcpu_to_fwft(vcpu);
> +
> + kfree(fwft->configs);
> +}
> +
> +const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_fwft = {
> + .extid_start = SBI_EXT_FWFT,
> + .extid_end = SBI_EXT_FWFT,
> + .handler = kvm_sbi_ext_fwft_handler,
> + .init = kvm_sbi_ext_fwft_init,
> + .deinit = kvm_sbi_ext_fwft_deinit,
> +};
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