Re: [PATCH 03/10] arm64: KVM: Save/restore the host SPE state when entering/leaving a VM

From: Marc Zyngier
Date: Thu Feb 02 2017 - 13:22:06 EST


On 02/02/17 18:18, Will Deacon wrote:
> On Wed, Feb 01, 2017 at 04:29:50PM +0000, Marc Zyngier wrote:
>> On 27/01/17 18:07, Will Deacon wrote:
>>> The SPE buffer is virtually addressed, using the page tables of the CPU
>>> MMU. Unusually, this means that the EL0/1 page table may be live whilst
>>> we're executing at EL2 on non-VHE configurations. When VHE is in use,
>>> we can use the same property to profile the guest behind its back.
>>>
>>> This patch adds the relevant disabling and flushing code to KVM so that
>>> the host can make use of SPE without corrupting guest memory, and any
>>> attempts by a guest to use SPE will result in a trap.
>>>
>>> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
>>> Cc: Alex Bennée <alex.bennee@xxxxxxxxxx>
>>> Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
>>> Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
>>> ---
>>> arch/arm64/include/asm/kvm_arm.h | 3 ++
>>> arch/arm64/include/asm/kvm_host.h | 7 ++++-
>>> arch/arm64/kvm/debug.c | 6 ++++
>>> arch/arm64/kvm/hyp/debug-sr.c | 66 +++++++++++++++++++++++++++++++++++++--
>>> arch/arm64/kvm/hyp/switch.c | 17 +++++++++-
>>> 5 files changed, 95 insertions(+), 4 deletions(-)
>
> [...]
>
>> Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>
> Thanks! Given that this patch depends on an earlier one in the series
> (already queued via arm64) and the rest of the series depends on this
> patch, do you mind if I take this via arm64 for 4.11? It applies cleanly
> against current -next.

Sure, that's fine by me. I don't foresee anything clashing with this
patch that we may queue for 4.11.

Thanks,

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