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From: Marc Zyngier <maz@kernel.org>
To: David Brazdil <dbrazdil@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	kernel-team@android.com,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Andrew Walbran <qwandor@google.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Quentin Perret <qperret@google.com>,
	linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
	linux-arm-kernel@lists.infradead.org, Tejun Heo <tj@kernel.org>,
	Dennis Zhou <dennis@kernel.org>, Christoph Lameter <cl@linux.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Andrew Scull <ascull@google.com>
Subject: Re: [PATCH v2 06/24] kvm: arm64: Move hyp-init params to a per-CPU struct
Date: Wed, 25 Nov 2020 10:49:18 +0000	[thread overview]
Message-ID: <643459b9146c5cdf91c3316bb1cb096e@kernel.org> (raw)
In-Reply-To: <20201125103946.2unmclsdfqpr3eyk@google.com>

On 2020-11-25 10:39, David Brazdil wrote:
> On Mon, Nov 23, 2020 at 02:20:07PM +0000, Marc Zyngier wrote:

[...]

>> > +
>> > +	/*
>> > +	 * Flush the init params from the data cache because the struct will
>> > +	 * be read while the MMU is off.
>> > +	 */
>> > +	__flush_dcache_area(params, sizeof(*params));
>> 
>> nit: please use kvm_flush_dcache_to_poc(), as it clearly indicates to
>> which point we are flushing.
> 
> Will change, but out of curiosity - how is it different? AFAICT, it is 
> just
> an alias with a single use in __clean_dcache_guest_page:
> 
>   #define kvm_flush_dcache_to_poc(a,l)	__flush_dcache_area((a), (l))

It is indeed the exact same thing, but it says clearly in the name that 
we
are cleaning to the "Point Of Coherency", as opposed to any other 
architectural level (Unification or Persistence).

It makes it clear that we are cleaning all the way to the point where it 
can
be accessed reliably with an uncacheable mapping, and not leaving the 
data
dangling at a shallower cache level.

Thanks,

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

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  reply	other threads:[~2020-11-25 10:49 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-16 20:42 [PATCH v2 00/24] Opt-in always-on nVHE hypervisor David Brazdil
2020-11-16 20:42 ` [PATCH v2 01/24] psci: Support psci_ops.get_version for v0.1 David Brazdil
2020-11-16 20:42 ` [PATCH v2 02/24] psci: Accessor for configured PSCI function IDs David Brazdil
2020-11-23 13:47   ` Marc Zyngier
2020-11-16 20:42 ` [PATCH v2 03/24] arm64: Make cpu_logical_map() take unsigned int David Brazdil
2020-11-16 20:42 ` [PATCH v2 04/24] arm64: Move MAIR_EL1_SET to asm/memory.h David Brazdil
2020-11-23 13:52   ` Marc Zyngier
2020-11-25 10:31     ` David Brazdil
2020-11-25 11:21       ` Marc Zyngier
2020-11-25 13:26         ` David Brazdil
2020-11-25 13:33           ` Marc Zyngier
2020-11-16 20:42 ` [PATCH v2 05/24] kvm: arm64: Initialize MAIR_EL2 using a constant David Brazdil
2020-11-16 20:43 ` [PATCH v2 06/24] kvm: arm64: Move hyp-init params to a per-CPU struct David Brazdil
2020-11-23 14:20   ` Marc Zyngier
2020-11-25 10:39     ` David Brazdil
2020-11-25 10:49       ` Marc Zyngier [this message]
2020-11-16 20:43 ` [PATCH v2 07/24] kvm: arm64: Refactor handle_trap to use a switch David Brazdil
2020-11-23 14:32   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 08/24] kvm: arm64: Add SMC handler in nVHE EL2 David Brazdil
2020-11-23 18:00   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 09/24] kvm: arm64: Add .hyp.data..ro_after_init ELF section David Brazdil
2020-11-16 20:43 ` [PATCH v2 10/24] kvm: arm64: Support per_cpu_ptr in nVHE hyp code David Brazdil
2020-11-16 20:43 ` [PATCH v2 11/24] kvm: arm64: Create nVHE copy of cpu_logical_map David Brazdil
2020-11-16 20:43 ` [PATCH v2 12/24] kvm: arm64: Bootstrap PSCI SMC handler in nVHE EL2 David Brazdil
2020-11-23 17:55   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 13/24] kvm: arm64: Add offset for hyp VA <-> PA conversion David Brazdil
2020-11-16 20:43 ` [PATCH v2 14/24] kvm: arm64: Forward safe PSCI SMCs coming from host David Brazdil
2020-11-16 20:43 ` [PATCH v2 15/24] kvm: arm64: Extract parts of el2_setup into a macro David Brazdil
2020-11-23 15:27   ` Marc Zyngier
2020-11-25 12:57     ` David Brazdil
2020-11-16 20:43 ` [PATCH v2 16/24] kvm: arm64: Extract __do_hyp_init into a helper function David Brazdil
2020-11-16 20:43 ` [PATCH v2 17/24] kvm: arm64: Add CPU entry point in nVHE hyp David Brazdil
2020-11-16 20:43 ` [PATCH v2 18/24] kvm: arm64: Add function to enter host from KVM nVHE hyp code David Brazdil
2020-11-16 20:43 ` [PATCH v2 19/24] kvm: arm64: Intercept host's PSCI_CPU_ON SMCs David Brazdil
2020-11-23 17:04   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 20/24] kvm: arm64: Intercept host's CPU_SUSPEND PSCI SMCs David Brazdil
2020-11-23 17:22   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 21/24] kvm: arm64: Add kvm-arm.protected early kernel parameter David Brazdil
2020-11-23 17:30   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 22/24] kvm: arm64: Keep nVHE EL2 vector installed David Brazdil
2020-11-16 20:43 ` [PATCH v2 23/24] kvm: arm64: Trap host SMCs in protected mode David Brazdil
2020-11-23 17:36   ` Marc Zyngier
2020-11-16 20:43 ` [PATCH v2 24/24] kvm: arm64: Fix EL2 mode availability checks David Brazdil
2020-11-23 13:44 ` [PATCH v2 00/24] Opt-in always-on nVHE hypervisor Marc Zyngier
2020-11-23 18:01 ` Marc Zyngier

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