On Wed, Jun 24, 2015 at 08:30:28PM -0700, Mario Smarduch wrote:
> This patch implements host KVM interface to Hyp mode VFP function to
> switch out guest and switch in host.
>
> Signed-off-by: Mario Smarduch <m.smarduch@xxxxxxxxxxx>
> ---
> arch/arm/kvm/arm.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index d9631ec..77b41f5 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -105,6 +105,17 @@ void kvm_arch_check_processor_compat(void *rtn)
> *(int *)rtn = 0;
> }
>
> +/**
> + * kvm_switch_vp_regs() - switch guest/host VFP registers
> + * @vcpu: pointer to vcpu structure.
> + *
> + * HYP interface functions to save guest and restore host VFP registers
Not sure I understand what you mean to say with this line, how about:
Calls an assembly routine in HYP mode to actually perform the state
save/restore.
However, why do we actually need to do this in hyp mode? Can't we just
as well do this in SVC mode or are we changing some trap settings here?
> + */
> +static void kvm_switch_fp_regs(struct kvm_vcpu *vcpu)
should probalby be called kvm_vcpu_put_fp_regs
> +{
> + if (vcpu->arch.vfp_guest_saved == 1)
> + kvm_call_hyp(__kvm_restore_host_vfp_state, vcpu);
> +}
>
> /**
> * kvm_arch_init_vm - initializes a VM data structure
> @@ -292,6 +303,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>
> void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
> {
> +
> + /* Check if Guest accessed VFP registers */
> + kvm_switch_fp_regs(vcpu);
> +
> /*
> * The arch-generic KVM code expects the cpu field of a vcpu to be -1
> * if the vcpu is no longer assigned to a cpu. This is used for the
> --
> 1.7.9.5
How are we sure that the kernel never touches VFP registers between VCPU
exit and kvm_arch_vcpu_put? Can a kernel-side memcpy implementation use
the FP regs or something like that?
Thanks,
-Christoffer
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