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Message-ID: <06b7539f-c5c0-843d-7617-a35a9f1d0e60@redhat.com>
Date: Wed, 13 Apr 2022 11:59:35 +0800
From: Gavin Shan <gshan@...hat.com>
To: Raghavendra Rao Ananta <rananta@...gle.com>,
Marc Zyngier <maz@...nel.org>,
Andrew Jones <drjones@...hat.com>,
James Morse <james.morse@....com>,
Alexandru Elisei <alexandru.elisei@....com>,
Suzuki K Poulose <suzuki.poulose@....com>
Cc: kvm@...r.kernel.org, Catalin Marinas <catalin.marinas@....com>,
Peter Shier <pshier@...gle.com>, linux-kernel@...r.kernel.org,
Paolo Bonzini <pbonzini@...hat.com>,
Will Deacon <will@...nel.org>, kvmarm@...ts.cs.columbia.edu,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v5 04/10] KVM: arm64: Add vendor hypervisor firmware
register
Hi Raghavendra,
On 4/7/22 9:15 AM, Raghavendra Rao Ananta wrote:
> Introduce the firmware register to hold the vendor specific
> hypervisor service calls (owner value 6) as a bitmap. The
> bitmap represents the features that'll be enabled for the
> guest, as configured by the user-space. Currently, this
> includes support for KVM-vendor features, and Precision Time
> Protocol (PTP), represented by bit-0 and bit-1 respectively.
>
> Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 2 ++
> arch/arm64/include/uapi/asm/kvm.h | 4 ++++
> arch/arm64/kvm/hypercalls.c | 21 +++++++++++++++++----
> include/kvm/arm_hypercalls.h | 4 ++++
> 4 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 20165242ebd9..b79161bad69a 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -106,10 +106,12 @@ struct kvm_arch_memory_slot {
> *
> * @std_bmap: Bitmap of standard secure service calls
> * @std_hyp_bmap: Bitmap of standard hypervisor service calls
> + * @vendor_hyp_bmap: Bitmap of vendor specific hypervisor service calls
> */
> struct kvm_smccc_features {
> u64 std_bmap;
> u64 std_hyp_bmap;
> + u64 vendor_hyp_bmap;
> };
>
> struct kvm_arch {
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 67353bf4e69d..9a5ac0ed4113 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -344,6 +344,10 @@ struct kvm_arm_copy_mte_tags {
> #define KVM_REG_ARM_STD_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(1)
> #define KVM_REG_ARM_STD_HYP_BIT_PV_TIME BIT(0)
>
> +#define KVM_REG_ARM_VENDOR_HYP_BMAP KVM_REG_ARM_FW_FEAT_BMAP_REG(2)
> +#define KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT BIT(0)
> +#define KVM_REG_ARM_VENDOR_HYP_BIT_PTP BIT(1)
> +
> /* Device Control API: ARM VGIC */
> #define KVM_DEV_ARM_VGIC_GRP_ADDR 0
> #define KVM_DEV_ARM_VGIC_GRP_DIST_REGS 1
> diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
> index 64ae6c7e7145..80836c341fd3 100644
> --- a/arch/arm64/kvm/hypercalls.c
> +++ b/arch/arm64/kvm/hypercalls.c
> @@ -66,8 +66,6 @@ static const u32 hvc_func_default_allowed_list[] = {
> ARM_SMCCC_VERSION_FUNC_ID,
> ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
> ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID,
> - ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID,
> - ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID,
> };
>
> static bool kvm_hvc_call_default_allowed(struct kvm_vcpu *vcpu, u32 func_id)
> @@ -102,6 +100,12 @@ static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
> case ARM_SMCCC_HV_PV_TIME_ST:
> return kvm_arm_fw_reg_feat_enabled(smccc_feat->std_hyp_bmap,
> KVM_REG_ARM_STD_HYP_BIT_PV_TIME);
> + case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
> + return kvm_arm_fw_reg_feat_enabled(smccc_feat->vendor_hyp_bmap,
> + KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT);
> + case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
> + return kvm_arm_fw_reg_feat_enabled(smccc_feat->vendor_hyp_bmap,
> + KVM_REG_ARM_VENDOR_HYP_BIT_PTP);
> default:
> return kvm_hvc_call_default_allowed(vcpu, func_id);
> }
I guess we may return SMCCC_RET_NOT_SUPPORTED for ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID
if KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT isn't set? Otherwise, we need explain it
in the commit log.
KVM_REG_ARM_VENDOR_HYP_BIT_{FUNC_FEAT, PTP} aren't parallel to each other.
I think PTP can't be on if KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT is off.
> @@ -194,8 +198,7 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
> val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
> break;
> case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
> - val[0] = BIT(ARM_SMCCC_KVM_FUNC_FEATURES);
> - val[0] |= BIT(ARM_SMCCC_KVM_FUNC_PTP);
> + val[0] = smccc_feat->vendor_hyp_bmap;
> break;
> case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
> kvm_ptp_get_time(vcpu, val);
> @@ -222,6 +225,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {
> KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
> KVM_REG_ARM_STD_BMAP,
> KVM_REG_ARM_STD_HYP_BMAP,
> + KVM_REG_ARM_VENDOR_HYP_BMAP,
> };
>
> void kvm_arm_init_hypercalls(struct kvm *kvm)
> @@ -230,6 +234,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)
>
> smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
> smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
> + smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
> }
>
> int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
> @@ -322,6 +327,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> case KVM_REG_ARM_STD_HYP_BMAP:
> val = READ_ONCE(smccc_feat->std_hyp_bmap);
> break;
> + case KVM_REG_ARM_VENDOR_HYP_BMAP:
> + val = READ_ONCE(smccc_feat->vendor_hyp_bmap);
> + break;
> default:
> return -ENOENT;
> }
> @@ -348,6 +356,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
> fw_reg_bmap = &smccc_feat->std_hyp_bmap;
> fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
> break;
> + case KVM_REG_ARM_VENDOR_HYP_BMAP:
> + fw_reg_bmap = &smccc_feat->vendor_hyp_bmap;
> + fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
> + break;
> default:
> return -ENOENT;
> }
If KVM_REG_ARM_VENDOR_HYP_BIT_{FUNC_FEAT, PTP} aren't parallel to each other,
special code is needed to gurantee PTP is cleared if VENDOR_HYP is disabled.
> @@ -453,6 +465,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
> return 0;
> case KVM_REG_ARM_STD_BMAP:
> case KVM_REG_ARM_STD_HYP_BMAP:
> + case KVM_REG_ARM_VENDOR_HYP_BMAP:
> return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
> default:
> return -ENOENT;
> diff --git a/include/kvm/arm_hypercalls.h b/include/kvm/arm_hypercalls.h
> index b0915d8c5b81..eaf4f6b318a8 100644
> --- a/include/kvm/arm_hypercalls.h
> +++ b/include/kvm/arm_hypercalls.h
> @@ -9,6 +9,7 @@
> /* Last valid bits of the bitmapped firmware registers */
> #define KVM_REG_ARM_STD_BMAP_BIT_MAX 0
> #define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX 0
> +#define KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX 1
>
> #define KVM_ARM_SMCCC_STD_FEATURES \
> GENMASK_ULL(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)
> @@ -16,6 +17,9 @@
> #define KVM_ARM_SMCCC_STD_HYP_FEATURES \
> GENMASK_ULL(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0)
>
> +#define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES \
> + GENMASK_ULL(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_MAX, 0)
> +
> int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);
>
> static inline u32 smccc_get_function(struct kvm_vcpu *vcpu)
>
Thanks,
Gavin
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