Re: [PATCH] kvm: arm64: fix caching of host MDCR_EL2 value

2018-10-17 Thread Robin Murphy
On 17/10/18 17:42, Mark Rutland wrote: At boot time, KVM stashes the host MDCR_EL2 value, but only does this when the kernel is not running in hyp mode (i.e. is non-VHE). In these cases, the stashed value of MDCR_EL2.HPMN happens to be zero, which can lead to CONSTRAINED UNPREDICTABLE behaviour.

Re: [PATCH] kvm: arm64: fix caching of host MDCR_EL2 value

2018-10-17 Thread Marc Zyngier
On 17/10/18 17:42, Mark Rutland wrote: > At boot time, KVM stashes the host MDCR_EL2 value, but only does this > when the kernel is not running in hyp mode (i.e. is non-VHE). In these > cases, the stashed value of MDCR_EL2.HPMN happens to be zero, which can > lead to CONSTRAINED UNPREDICTABLE

[PATCH] kvm: arm64: fix caching of host MDCR_EL2 value

2018-10-17 Thread Mark Rutland
At boot time, KVM stashes the host MDCR_EL2 value, but only does this when the kernel is not running in hyp mode (i.e. is non-VHE). In these cases, the stashed value of MDCR_EL2.HPMN happens to be zero, which can lead to CONSTRAINED UNPREDICTABLE behaviour. Since we use this value to derive the