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From: Steven Price <steven.price@arm.com>
To: "yezengruan@huawei.com" <yezengruan@huawei.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>,
	"maz@kernel.org" <maz@kernel.org>,
	James Morse <James.Morse@arm.com>,
	"linux@armlinux.org.uk" <linux@armlinux.org.uk>,
	Suzuki Poulose <Suzuki.Poulose@arm.com>,
	"julien.thierry.kdev@gmail.com" <julien.thierry.kdev@gmail.com>,
	Catalin Marinas <Catalin.Marinas@arm.com>,
	Mark Rutland <Mark.Rutland@arm.com>,
	"will@kernel.org" <will@kernel.org>,
	"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>
Subject: Re: [PATCH 2/5] KVM: arm64: Implement PV_LOCK_FEATURES call
Date: Tue, 17 Dec 2019 14:28:48 +0000
Message-ID: <20191217142848.GB38811@arm.com> (raw)
In-Reply-To: <20191217135549.3240-3-yezengruan@huawei.com>

On Tue, Dec 17, 2019 at 01:55:46PM +0000, yezengruan@huawei.com wrote:
> From: Zengruan Ye <yezengruan@huawei.com>
> 
> This provides a mechanism for querying which paravirtualized lock
> features are available in this hypervisor.
> 
> Also add the header file which defines the ABI for the paravirtualized
> lock features we're about to add.
> 
> Signed-off-by: Zengruan Ye <yezengruan@huawei.com>
> ---
>  arch/arm64/include/asm/pvlock-abi.h | 16 ++++++++++++++++
>  include/linux/arm-smccc.h           | 13 +++++++++++++
>  virt/kvm/arm/hypercalls.c           |  3 +++
>  3 files changed, 32 insertions(+)
>  create mode 100644 arch/arm64/include/asm/pvlock-abi.h
> 
> diff --git a/arch/arm64/include/asm/pvlock-abi.h b/arch/arm64/include/asm/pvlock-abi.h
> new file mode 100644
> index 000000000000..06e0c3d7710a
> --- /dev/null
> +++ b/arch/arm64/include/asm/pvlock-abi.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright(c) 2019 Huawei Technologies Co., Ltd
> + * Author: Zengruan Ye <yezengruan@huawei.com>
> + */
> +
> +#ifndef __ASM_PVLOCK_ABI_H
> +#define __ASM_PVLOCK_ABI_H
> +
> +struct pvlock_vcpu_state {
> +	__le64 preempted;

Somewhere we need to document when 'preempted' is. It looks like it's a
1-bit field from the later patches.

> +	/* Structure must be 64 byte aligned, pad to that size */
> +	u8 padding[56];
> +} __packed;
> +
> +#endif
> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> index 59494df0f55b..59e65a951959 100644
> --- a/include/linux/arm-smccc.h
> +++ b/include/linux/arm-smccc.h
> @@ -377,5 +377,18 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
>  			   ARM_SMCCC_OWNER_STANDARD_HYP,	\
>  			   0x21)
>  
> +/* Paravirtualised lock calls */
> +#define ARM_SMCCC_HV_PV_LOCK_FEATURES				\
> +	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
> +			   ARM_SMCCC_SMC_64,			\
> +			   ARM_SMCCC_OWNER_STANDARD_HYP,	\
> +			   0x40)
> +
> +#define ARM_SMCCC_HV_PV_LOCK_PREEMPTED				\
> +	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
> +			   ARM_SMCCC_SMC_64,			\
> +			   ARM_SMCCC_OWNER_STANDARD_HYP,	\
> +			   0x41)
> +
>  #endif /*__ASSEMBLY__*/
>  #endif /*__LINUX_ARM_SMCCC_H*/
> diff --git a/virt/kvm/arm/hypercalls.c b/virt/kvm/arm/hypercalls.c
> index 550dfa3e53cd..ff13871fd85a 100644
> --- a/virt/kvm/arm/hypercalls.c
> +++ b/virt/kvm/arm/hypercalls.c
> @@ -52,6 +52,9 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
>  		case ARM_SMCCC_HV_PV_TIME_FEATURES:
>  			val = SMCCC_RET_SUCCESS;
>  			break;
> +		case ARM_SMCCC_HV_PV_LOCK_FEATURES:
> +			val = SMCCC_RET_SUCCESS;
> +			break;

Ideally you wouldn't report that PV_LOCK_FEATURES exists until the
actual hypercalls are wired up to avoid breaking a bisect.

Steve

>  		}
>  		break;
>  	case ARM_SMCCC_HV_PV_TIME_FEATURES:
> -- 
> 2.19.1
> 
> 

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-17 13:55 [PATCH 0/5] KVM: arm64: vcpu preempted check support yezengruan
2019-12-17 13:55 ` [PATCH 1/5] KVM: arm64: Document PV-lock interface yezengruan
2019-12-17 14:21   ` Steven Price
2019-12-19 11:45     ` yezengruan
2019-12-20 11:43       ` Steven Price
2019-12-20 14:32   ` Markus Elfring
2019-12-23  2:06     ` yezengruan
2019-12-17 13:55 ` [PATCH 2/5] KVM: arm64: Implement PV_LOCK_FEATURES call yezengruan
2019-12-17 14:28   ` Steven Price [this message]
2019-12-19 11:59     ` yezengruan
2019-12-17 13:55 ` [PATCH 3/5] KVM: arm64: Support pvlock preempted via shared structure yezengruan
2019-12-17 14:33   ` Steven Price
2019-12-26  8:33     ` yezengruan
2019-12-17 13:55 ` [PATCH 4/5] KVM: arm64: Add interface to support vcpu preempted check yezengruan
2019-12-17 13:55 ` [PATCH 5/5] KVM: arm64: Support the vcpu preemption check yezengruan
2019-12-17 14:40   ` Steven Price
2019-12-26  8:34     ` yezengruan

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