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From: Marc Zyngier <maz@kernel.org>
To: Andrew Scull <ascull@google.com>
Cc: kvm@vger.kernel.org, Suzuki K Poulose <suzuki.poulose@arm.com>,
	James Morse <james.morse@arm.com>,
	linux-arm-kernel@lists.infradead.org, kernel-team@android.com,
	kvmarm@lists.cs.columbia.edu,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: Re: [PATCH 1/4] KVM: arm64: Enable Pointer Authentication at EL2 if available
Date: Mon, 15 Jun 2020 11:45:08 +0100	[thread overview]
Message-ID: <8683c038040236e1fefed067649c31d9@kernel.org> (raw)
In-Reply-To: <20200615084857.GD177680@google.com>

Hi Andrew,

On 2020-06-15 09:48, Andrew Scull wrote:
> On Mon, Jun 15, 2020 at 09:19:51AM +0100, Marc Zyngier wrote:
>> While initializing EL2, switch Pointer Authentication if detected
> 
>                                 ^ nit: on?

Yes.

> 
>> from EL1. We use the EL1-provided keys though.
>> 
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>> ---
>>  arch/arm64/kvm/hyp-init.S | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>> 
>> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
>> index 6e6ed5581eed..81732177507d 100644
>> --- a/arch/arm64/kvm/hyp-init.S
>> +++ b/arch/arm64/kvm/hyp-init.S
>> @@ -104,6 +104,17 @@ alternative_else_nop_endif
>>  	 */
>>  	mov_q	x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
>>  CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
>> +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
>> +	b	1f
>> +alternative_else_nop_endif
>> +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
>> +	b	2f
>> +alternative_else_nop_endif
>> +1:
>> +	orr	x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB)
>> +	orr	x4, x4, #SCTLR_ELx_ENDA
>> +	orr	x4, x4, #SCTLR_ELx_ENDB
> 
> mm/proc.S builds the mask with ldr and ors it in one go, would be nice
> to use the same pattern.

Do you actually mean kernel/head.S, or even __ptrauth_keys_init_cpu in 
asm/asm_pointer_auth.h?

If so, I agree that it'd be good to make it look similar by using the 
mov_q macro, at the expense of a spare register (which we definitely can 
afford here).

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...

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  reply	other threads:[~2020-06-15 10:45 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15  8:19 [PATCH 0/4] KVM/arm64: Enable PtrAuth on non-VHE KVM Marc Zyngier
2020-06-15  8:19 ` [PATCH 1/4] KVM: arm64: Enable Pointer Authentication at EL2 if available Marc Zyngier
2020-06-15  8:48   ` Andrew Scull
2020-06-15 10:45     ` Marc Zyngier [this message]
2020-06-15 10:03   ` Mark Rutland
2020-06-15 10:55     ` Marc Zyngier
2020-06-15  8:19 ` [PATCH 2/4] KVM: arm64: Allow ARM64_PTR_AUTH when ARM64_VHE=n Marc Zyngier
2020-06-15  8:58   ` Andrew Scull
2020-06-15 10:12   ` Mark Rutland
2020-06-15  8:19 ` [PATCH 3/4] KVM: arm64: Allow PtrAuth to be enabled from userspace on non-VHE systems Marc Zyngier
2020-06-15  9:09   ` Andrew Scull
2020-06-15 10:16   ` Mark Rutland
2020-06-15  8:19 ` [PATCH 4/4] KVM: arm64: Check HCR_EL2 instead of shadow copy to swap PtrAuth registers Marc Zyngier
2020-06-15 10:25   ` Mark Rutland
2020-06-15 12:59 ` [PATCH 0/4] KVM/arm64: Enable PtrAuth on non-VHE KVM Dave Martin
2020-06-15 13:22   ` Marc Zyngier
2020-06-15 14:17     ` Dave Martin

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