Hi Sudeep, On 23/05/2019 11:34, Sudeep Holla wrote: > If we enable profiling buffer controls at EL1 generate a trap exception > to EL2, it also changes profiling buffer to use EL1&0 stage 1 translation > regime in case of VHE. To support SPE both in the guest and host, we > need to first stop profiling and flush the profiling buffers before > we activate/switch vm or enable/disable the traps. > > In prepartion to do that, lets split the debug save restore functionality > into 4 steps: > 1. debug_save_host_context - saves the host context > 2. debug_restore_guest_context - restore the guest context > 3. debug_save_guest_context - saves the guest context > 4. debug_restore_host_context - restores the host context > > Lets rename existing __debug_switch_to_{host,guest} to make sure it's > aligned to the above and just add the place holders for new ones getting > added here as we need them to support SPE in guests. > > Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com> > --- > arch/arm64/include/asm/kvm_hyp.h | 6 ++++-- > arch/arm64/kvm/hyp/debug-sr.c | 25 ++++++++++++++++--------- > arch/arm64/kvm/hyp/switch.c | 12 ++++++++---- > 3 files changed, 28 insertions(+), 15 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_hyp.h > b/arch/arm64/include/asm/kvm_hyp.h > index 782955db61dd..1c5ed80fcbda 100644 > --- a/arch/arm64/include/asm/kvm_hyp.h > +++ b/arch/arm64/include/asm/kvm_hyp.h > @@ -164,8 +164,10 @@ void sysreg_restore_guest_state_vhe(struct > kvm_cpu_context *ctxt); > void __sysreg32_save_state(struct kvm_vcpu *vcpu); > void __sysreg32_restore_state(struct kvm_vcpu *vcpu); > > -void __debug_switch_to_guest(struct kvm_vcpu *vcpu); > -void __debug_switch_to_host(struct kvm_vcpu *vcpu); > +void __debug_save_host_context(struct kvm_vcpu *vcpu); > +void __debug_restore_guest_context(struct kvm_vcpu *vcpu); > +void __debug_save_guest_context(struct kvm_vcpu *vcpu); > +void __debug_restore_host_context(struct kvm_vcpu *vcpu); > > void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); > void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); > diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c > index fa51236ebcb3..618884df1dc4 100644 > --- a/arch/arm64/kvm/hyp/debug-sr.c > +++ b/arch/arm64/kvm/hyp/debug-sr.c > @@ -149,20 +149,13 @@ static void __hyp_text __debug_restore_state(struct > kvm_vcpu *vcpu, > write_sysreg(ctxt->sys_regs[MDCCINT_EL1], mdccint_el1); > } > > -void __hyp_text __debug_switch_to_guest(struct kvm_vcpu *vcpu) > +void __hyp_text __debug_restore_guest_context(struct kvm_vcpu *vcpu) > { > struct kvm_cpu_context *host_ctxt; > struct kvm_cpu_context *guest_ctxt; > struct kvm_guest_debug_arch *host_dbg; > struct kvm_guest_debug_arch *guest_dbg; > > - /* > - * Non-VHE: Disable and flush SPE data generation > - * VHE: The vcpu can run, but it can't hide. > - */ > - if (!has_vhe()) > - __debug_save_spe_nvhe(&vcpu->arch.host_debug_state.pmscr_el1); > - > if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY)) > return; > > @@ -175,7 +168,7 @@ void __hyp_text __debug_switch_to_guest(struct kvm_vcpu > *vcpu) > __debug_restore_state(vcpu, guest_dbg, guest_ctxt); > } > > -void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu) > +void __hyp_text __debug_restore_host_context(struct kvm_vcpu *vcpu)
In the current state of the sources, __debug_switch_to_host() seems to save the guest debug state before restoring the host's: __debug_save_state(vcpu, guest_dbg, guest_ctxt); Since you're splitting the switch_to into save/restore operations, it feels like this would fit better __debug_save_guest_context() (currently empty) rather than __debug_restore_host_context(). Cheers, -- Julien Thierry