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From: Catalin Marinas <catalin.marinas@arm.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>,
	Christoffer Dall <christoffer.dall@linaro.org>,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Subject: Re: [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if running in HYP
Date: Mon, 8 Feb 2016 15:56:26 +0000	[thread overview]
Message-ID: <20160208155625.GQ6076@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1454522416-6874-22-git-send-email-marc.zyngier@arm.com>

On Wed, Feb 03, 2016 at 06:00:14PM +0000, Marc Zyngier wrote:
> @@ -76,6 +59,36 @@ static inline void decode_ctrl_reg(u32 reg,
>  #define ARM_KERNEL_STEP_ACTIVE	1
>  #define ARM_KERNEL_STEP_SUSPEND	2
>  
> +#define DBG_HMC_HYP		(1 << 13)
> +#define DBG_SSC_HYP		(3 << 14)
> +
> +static inline u32 encode_ctrl_reg(struct arch_hw_breakpoint_ctrl ctrl)
> +{
> +	u32 val = (ctrl.len << 5) | (ctrl.type << 3) | ctrl.enabled;
> +
> +	if (is_kernel_in_hyp_mode() && ctrl.privilege == AARCH64_BREAKPOINT_EL1)
> +		val |= DBG_HMC_HYP | DBG_SSC_HYP;
> +	else
> +		val |= ctrl.privilege << 1;
> +
> +	return val;
> +}
> +
> +static inline void decode_ctrl_reg(u32 reg,
> +				   struct arch_hw_breakpoint_ctrl *ctrl)
> +{
> +	ctrl->enabled	= reg & 0x1;
> +	reg >>= 1;
> +	if (is_kernel_in_hyp_mode())
> +		ctrl->privilege = !!(reg & (DBG_HMC_HYP >> 1));

I don't particularly like this part as it's not clear just by looking at
the code that it, in fact, generates AARCH64_BREAKPOINT_EL1. I would
make this clearer:

	if (is_kernel_in_hyp_mode() && (reg & (DBG_HMC_HYP >> 1)))
		ctrl->privilege = AARCH64_BREAKPOINT_EL1;

Alternatively, you could define the PMC field value as:

#define AARCH64_BREAKPOINT_EL2	0

and change the privilege to EL1 after masking, something like:

	ctrl->privilege = reg & 0x3;
	if (ctrl->privilege == AARCH64_BREAKPOINT_EL2)
		ctrl->privilege = AARCH64_BREAKPOINT_EL1;

BTW, do we need to check is_kernel_in_hyp_mode() when decoding? Is there
anything else that could have set this SSC/HMC/PMC fields other than
encode_ctrl_reg()?

-- 
Catalin

  reply	other threads:[~2016-02-08 15:56 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-03 17:59 [PATCH v3 00/23] arm64: Virtualization Host Extension support Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 01/23] arm/arm64: KVM: Add hook for C-based stage2 init Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 02/23] arm64: KVM: Switch to " Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 03/23] arm/arm64: Add new is_kernel_in_hyp_mode predicate Marc Zyngier
2016-02-08 14:41   ` Catalin Marinas
2016-02-03 17:59 ` [PATCH v3 04/23] arm64: Allow the arch timer to use the HYP timer Marc Zyngier
2016-02-03 17:59 ` [PATCH v3 05/23] arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature Marc Zyngier
2016-02-08 14:42   ` Catalin Marinas
2016-02-03 17:59 ` [PATCH v3 06/23] arm64: KVM: Skip HYP setup when already running in HYP Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 07/23] arm64: KVM: VHE: Patch out use of HVC Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 08/23] arm64: KVM: VHE: Patch out kern_hyp_va Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 09/23] arm64: KVM: VHE: Introduce unified system register accessors Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 10/23] arm64: KVM: VHE: Differenciate host/guest sysreg save/restore Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 11/23] arm64: KVM: VHE: Split save/restore of registers shared between guest and host Marc Zyngier
2016-02-04 19:15   ` Christoffer Dall
2016-02-03 18:00 ` [PATCH v3 12/23] arm64: KVM: VHE: Use unified system register accessors Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 13/23] arm64: KVM: VHE: Enable minimal sysreg save/restore Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 14/23] arm64: KVM: VHE: Make __fpsimd_enabled VHE aware Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 15/23] arm64: KVM: VHE: Implement VHE activate/deactivate_traps Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 16/23] arm64: KVM: VHE: Use unified sysreg accessors for timer Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 17/23] arm64: KVM: VHE: Add fpsimd enabling on guest access Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 18/23] arm64: KVM: VHE: Add alternative panic handling Marc Zyngier
2016-02-03 18:00 ` [PATCH v3 19/23] arm64: KVM: Move most of the fault decoding to C Marc Zyngier
2016-02-04 19:20   ` Christoffer Dall
2016-02-08 14:44   ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 20/23] arm64: perf: Count EL2 events if the kernel is running in HYP Marc Zyngier
2016-02-04 19:23   ` Christoffer Dall
2016-02-05  9:02     ` Marc Zyngier
2016-02-08 14:48   ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 21/23] arm64: hw_breakpoint: Allow EL2 breakpoints if " Marc Zyngier
2016-02-08 15:56   ` Catalin Marinas [this message]
2016-02-08 16:45     ` Marc Zyngier
2016-02-08 16:52       ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 22/23] arm64: VHE: Add support for running Linux in EL2 mode Marc Zyngier
2016-02-04 19:25   ` Christoffer Dall
2016-02-08 15:58   ` Catalin Marinas
2016-02-03 18:00 ` [PATCH v3 23/23] arm64: Panic when VHE and non VHE CPUs coexist Marc Zyngier
2016-02-04 19:25   ` Christoffer Dall
2016-02-08 16:04   ` Catalin Marinas
2016-02-08 16:24     ` Mark Rutland
2016-02-09 12:02       ` Catalin Marinas
2016-02-04 19:26 ` [PATCH v3 00/23] arm64: Virtualization Host Extension support Christoffer Dall
2016-02-05  8:56   ` Marc Zyngier

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