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

From: Will Deacon
Date: Thu Feb 02 2017 - 13:18:16 EST


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.

Will