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From: David Brazdil <dbrazdil@google.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Andrew Walbran <qwandor@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
	Tejun Heo <tj@kernel.org>, Dennis Zhou <dennis@kernel.org>,
	Christoph Lameter <cl@linux.com>,
	kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v1 23/24] kvm: arm64: Trap host SMCs in protected mode.
Date: Tue, 10 Nov 2020 13:00:49 +0000	[thread overview]
Message-ID: <20201110130049.pwc4ilqy2ue2ydvu@google.com> (raw)
In-Reply-To: <10952bcf24bebd5e317d09ced415bfb1@kernel.org>

> > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
> > @@ -88,6 +88,12 @@ SYM_CODE_END(__kvm_hyp_init)
> >   * x0: struct kvm_nvhe_init_params PA
> >   */
> >  SYM_CODE_START(___kvm_hyp_init)
> > +alternative_cb kvm_patch_hcr_flags
> > +	mov_q	x1, HCR_HOST_NVHE_FLAGS
> 
> You really want to be careful here: the mov_q macro expands to 2, 3 or 4
> instructions, depending on the input data...
> 
> It is also odd that you have both a static key and a patching alternative.
> Why isn't "protected KVM" a capability that can be evaluated as a a non
> patching alternative? In general, I'd like to reserve patching alternatives
> to values that cannot be evaluated at compile time (VM offsets, for
> example).

Capability was my initial idea as well but it looked tied to CPU features.
Looking at it again, you're right that there is precedent for setting them
from kernel params. Alright, I'll change it and that will get rid of the
custom patching.

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  reply	other threads:[~2020-11-10 13:01 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 11:32 [PATCH v1 00/24] Opt-in always-on nVHE hypervisor David Brazdil
2020-11-09 11:32 ` [PATCH v1 01/24] psci: Accessor for configured PSCI version David Brazdil
2020-11-10 14:43   ` Marc Zyngier
2020-11-11 11:31     ` David Brazdil
2020-11-09 11:32 ` [PATCH v1 02/24] psci: Accessor for configured PSCI function IDs David Brazdil
2020-11-09 11:32 ` [PATCH v1 03/24] arm64: Move MAIR_EL1_SET to asm/memory.h David Brazdil
2020-11-10 14:49   ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 04/24] kvm: arm64: Initialize MAIR_EL2 using a constant David Brazdil
2020-11-09 11:32 ` [PATCH v1 05/24] kvm: arm64: Add .hyp.data..ro_after_init ELF section David Brazdil
2020-11-09 11:32 ` [PATCH v1 06/24] kvm: arm64: Support per_cpu_ptr in nVHE hyp code David Brazdil
2020-11-10 15:08   ` Marc Zyngier
2020-11-11 12:32     ` David Brazdil
2020-11-11 12:46       ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 07/24] kvm: arm64: Create nVHE copy of cpu_logical_map David Brazdil
2020-11-10 15:24   ` Marc Zyngier
2020-11-11 13:03     ` David Brazdil
2020-11-11 13:29       ` Marc Zyngier
2020-11-11 13:45         ` David Brazdil
2020-11-11 13:52           ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 08/24] kvm: arm64: Move hyp-init params to a per-CPU struct David Brazdil
2020-11-10 15:30   ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 09/24] kvm: arm64: Refactor handle_trap to use a switch David Brazdil
2020-11-09 11:32 ` [PATCH v1 10/24] kvm: arm64: Extract parts of el2_setup into a macro David Brazdil
2020-11-10 15:56   ` Marc Zyngier
2020-11-16 17:56     ` David Brazdil
2020-11-09 11:32 ` [PATCH v1 11/24] kvm: arm64: Add SMC handler in nVHE EL2 David Brazdil
2020-11-11 12:12   ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 12/24] kvm: arm64: Extract __do_hyp_init into a helper function David Brazdil
2020-11-09 11:32 ` [PATCH v1 13/24] kvm: arm64: Add CPU entry point in nVHE hyp David Brazdil
2020-11-11 11:57   ` Marc Zyngier
2020-11-16 11:49     ` David Brazdil
2020-11-16 12:40       ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 14/24] kvm: arm64: Add function to enter host from KVM nVHE hyp code David Brazdil
2020-11-09 11:32 ` [PATCH v1 15/24] kvm: arm64: Bootstrap PSCI SMC handler in nVHE EL2 David Brazdil
2020-11-11 13:18   ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 16/24] kvm: arm64: Add offset for hyp VA <-> PA conversion David Brazdil
2020-11-11 13:47   ` Marc Zyngier
2020-11-09 11:32 ` [PATCH v1 17/24] kvm: arm64: Add __hyp_pa_symbol helper macro David Brazdil
2020-11-09 16:59   ` Quentin Perret
2020-11-09 18:10     ` Marc Zyngier
2020-11-10  9:24       ` David Brazdil
2020-11-09 11:32 ` [PATCH v1 18/24] kvm: arm64: Forward safe PSCI SMCs coming from host David Brazdil
2020-11-09 11:32 ` [PATCH v1 19/24] kvm: arm64: Intercept host's PSCI_CPU_ON SMCs David Brazdil
2020-11-09 11:32 ` [PATCH v1 20/24] kvm: arm64: Intercept host's CPU_SUSPEND PSCI SMCs David Brazdil
2020-11-09 11:32 ` [PATCH v1 21/24] kvm: arm64: Add kvm-arm.protected early kernel parameter David Brazdil
2020-11-09 11:32 ` [PATCH v1 22/24] kvm: arm64: Keep nVHE EL2 vector installed David Brazdil
2020-11-09 11:32 ` [PATCH v1 23/24] kvm: arm64: Trap host SMCs in protected mode David Brazdil
2020-11-10  5:02   ` kernel test robot
2020-11-10  9:03   ` Marc Zyngier
2020-11-10 13:00     ` David Brazdil [this message]
2020-11-09 11:32 ` [PATCH v1 24/24] kvm: arm64: Fix EL2 mode availability checks David Brazdil
2020-11-10 10:15 ` [PATCH v1 00/24] Opt-in always-on nVHE hypervisor Christoph Hellwig
2020-11-10 11:18   ` Marc Zyngier
2021-01-19 13:17     ` Janne Karhunen
2020-11-11 14:32 ` Marc Zyngier

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