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From: catalin.marinas@arm.com (Catalin Marinas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 18/23] arm64: KVM: Add epilogue branching to the vector code
Date: Thu, 8 Mar 2018 13:59:02 +0000	[thread overview]
Message-ID: <20180308135902.olhvrydbcszjl3ap@armageddon.cambridge.arm.com> (raw)
In-Reply-To: <20180301155538.26860-19-marc.zyngier@arm.com>

On Thu, Mar 01, 2018 at 03:55:33PM +0000, Marc Zyngier wrote:
> We are soon going to have to do some extra work in the BP hardening
> vector slots. Instead of doing that work in the vectors themselves
> (which would massively reduce the space available to deal with
> Spectre v2), let's branch to an epilogue where we can do "stuff".
> 
> This has a number of consequences:
> - We need some free registers, so we're spilling x0 and x1 on the
>   stack
> - In order to counterbalance this, we branch to the *second* instruction
>   in the vectors, avoiding the initial store that is already there
>   (or loading the registers back if we've branched to a panic vector)
> 
> This is all controlled by a new capability (ARM64_HARDEN_EL2_VECTORS)
> which doesn't get enabled yet.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

That's mostly kvm but anyway:

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

  reply	other threads:[~2018-03-08 13:59 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-01 15:55 [PATCH v5 00/23] KVM/arm64: Randomise EL2 mappings (variant 3a mitigation) Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 01/23] arm64: alternatives: Add dynamic patching feature Marc Zyngier
2018-03-07 18:09   ` Catalin Marinas
2018-03-01 15:55 ` [PATCH v5 02/23] arm64: insn: Add N immediate encoding Marc Zyngier
2018-03-07 18:09   ` Catalin Marinas
2018-03-01 15:55 ` [PATCH v5 03/23] arm64: insn: Add encoder for bitwise operations using literals Marc Zyngier
2018-03-07 18:10   ` Catalin Marinas
2018-03-12 14:44   ` Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 04/23] arm64: KVM: Dynamically patch the kernel/hyp VA mask Marc Zyngier
2018-03-07 18:10   ` Catalin Marinas
2018-03-01 15:55 ` [PATCH v5 05/23] arm64: cpufeatures: Drop the ARM64_HYP_OFFSET_LOW feature flag Marc Zyngier
2018-03-07 18:11   ` Catalin Marinas
2018-03-13  8:44   ` Suzuki K Poulose
2018-03-01 15:55 ` [PATCH v5 06/23] KVM: arm/arm64: Do not use kern_hyp_va() with kvm_vgic_global_state Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 07/23] KVM: arm/arm64: Demote HYP VA range display to being a debug feature Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 08/23] KVM: arm/arm64: Move ioremap calls to create_hyp_io_mappings Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 09/23] KVM: arm/arm64: Keep GICv2 HYP VAs in kvm_vgic_global_state Marc Zyngier
2018-03-13  9:35   ` Suzuki K Poulose
2018-03-13 11:40     ` Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 10/23] KVM: arm/arm64: Move HYP IO VAs to the "idmap" range Marc Zyngier
2018-03-09 18:59   ` James Morse
2018-03-12 14:02     ` Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 11/23] arm64; insn: Add encoder for the EXTR instruction Marc Zyngier
2018-03-07 18:12   ` Catalin Marinas
2018-03-01 15:55 ` [PATCH v5 12/23] arm64: insn: Allow ADD/SUB (immediate) with LSL #12 Marc Zyngier
2018-03-07 18:13   ` Catalin Marinas
2018-03-01 15:55 ` [PATCH v5 13/23] arm64: KVM: Dynamically compute the HYP VA mask Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 14/23] arm64: KVM: Introduce EL2 VA randomisation Marc Zyngier
2018-03-13 11:31   ` James Morse
2018-03-13 11:48     ` James Morse
2018-03-01 15:55 ` [PATCH v5 15/23] arm64: Update the KVM memory map documentation Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 16/23] arm64: KVM: Move vector offsetting from hyp-init.S to kvm_get_hyp_vector Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 17/23] arm64: KVM: Move stashing of x0/x1 into the vector code itself Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 18/23] arm64: KVM: Add epilogue branching to the vector code Marc Zyngier
2018-03-08 13:59   ` Catalin Marinas [this message]
2018-03-01 15:55 ` [PATCH v5 19/23] arm64: KVM: Allow far branches from vector slots to the main vectors Marc Zyngier
2018-03-08 13:59   ` Catalin Marinas
2018-03-12 18:27   ` James Morse
2018-03-12 19:43     ` Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 20/23] arm/arm64: KVM: Introduce EL2-specific executable mappings Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 21/23] arm64: Make BP hardening slot counter available Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 22/23] arm64: KVM: Allow mapping of vectors outside of the RAM region Marc Zyngier
2018-03-08 17:54   ` Andrew Jones
2018-03-13 10:30     ` Marc Zyngier
2018-03-13 11:14       ` Andrew Jones
2018-03-09 18:59   ` James Morse
2018-03-12 14:23     ` Marc Zyngier
2018-03-14 11:40   ` James Morse
2018-03-14 12:02     ` Marc Zyngier
2018-03-01 15:55 ` [PATCH v5 23/23] arm64: Enable ARM64_HARDEN_EL2_VECTORS on Cortex-A57 and A72 Marc Zyngier

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