[PATCH v2] arm64: head.S: Fix CNTHCTL_EL2 access on VHE system

[Catalin Marinas]

On Mon, Nov 28, 2016 at 09:13:02PM -0500, Jintack Lim wrote:
> From: Jintack <jintack at cs.columbia.edu>
> 
> Bit positions of CNTHCTL_EL2 are changing depending on HCR_EL2.E2H bit.
> EL1PCEN and EL1PCTEN are 1st and 0th bits when E2H is not set, but they
> are 11th and 10th bits respectively when E2H is set.  Current code is
> unintentionally setting wrong bits to CNTHCTL_EL2 with E2H set.
> 
> In fact, we don't need to set those two bits, which allow EL1 and EL0 to
> access physical timer and counter respectively, if E2H and TGE are set
> for the host kernel. They will be configured later as necessary. First,
> we don't need to configure those bits for EL1, since the host kernel
> runs in EL2.  It is a hypervisor's responsibility to configure them
> before entering a VM, which runs in EL0 and EL1. Second, EL0 accesses
> are configured in the later stage of boot process.
> 
> Signed-off-by: Jintack Lim <jintack at cs.columbia.edu>
> Acked-by: Marc Zyngier <marc.zyngier at arm.com>

Queued for 4.10. Thanks.

-- 
Catalin