[kvmarm] [PATCH 10/15] KVM: ARM: World-switch implementation

Christoffer Dall c.dall at virtualopensystems.com
Sun Sep 30 10:31:36 EDT 2012

On Sun, Sep 30, 2012 at 5:48 AM, Peter Maydell <peter.maydell at linaro.org> wrote:
> On 30 September 2012 01:33, Christoffer Dall
> <c.dall at virtualopensystems.com> wrote:
>> On Tue, Sep 25, 2012 at 1:42 PM, Marc Zyngier <marc.zyngier at arm.com> wrote:
>>> Well, we're still in HYP mode when performing the pop, so the VMID is
>>> pretty much irrelevant. Same for the initial push, actually. As long as
>>> we're sure VTTBR has been updated when we do the exception return, I think
>>> we're safe.
>> yeah we're safe, but I can't find anywhere that says the ISB is
>> implied from exception handling/hvc, even though I seem to recall
>> having read this, so I put this here not to worry other readers.
> "TLB maintenance operations and the memory order model" in section
> B3.10.1 of the ARM ARM says that exception entry forces completion of
> TLB maintenance ops. Section B5.6.3 ("Synchronization of changes to
> system control registers") says that taking an exception synchronizes
> context, so the VTTBR update is guaranteed to have happened.
thanks - I was counting on your help here :)


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