On Mon, 23 Jul 2012 20:21:28 +0100, Peter Maydell <peter.maydell at linaro.org> wrote: > On 23 July 2012 19:41, Antonios Motakis > <a.motakis at virtualopensystems.com> wrote: > > This patch applies to the v9 patch series of KVM, > > i.e. commit d5321dceeaccf756755e76b38d8b5905bd99d250 > > > > In this patch, we use the Hyp Coprocessor Trap Register > > (HPCTR) to trap VFP/NEON instructions, and switch the FPU > > state at that point. After a guest exit, the VFP state is > > returned to the host. > > We need to also expose the guest VFP state to userspace > for save/restore, but since I think that should be done > via the same ioctls Rusty has proposed for cp15 save/load > we should do that in a later patch I think. Agreed. > > + /* Floating point registers (VFP and Advanced SIMD/NEON) */ > > + u32 guest_cp10[nr_cp10_regs]; > > + u32 guest_cp11[64]; > > + > > + /* Saved host vfp state. */ > > + u32 host_cp10[nr_cp10_regs]; > > + u32 host_cp11[64]; > > I notice that this is saving basically the same info as vfp_hard_struct > in arch/arm/include/asm/fpstate.h, but with more opaque structure field > names. Does it make sense to reuse that struct (and perhaps even > the vfp_save_state/vfp_restore_state functions)? OK, I think we should reuse vfp_hard_struct (and ignore the 'cpu' field). I'd use vfp_save_state/vfp_restore_state in a separate follow-up patch, since we'd have to write vfp_restore_state, and should add a comment noting that they can now be called from hyp mode. Cheers, Rusty.
