Re: [PATCH v2 07/15] arm64: KVM: split debug save restore across vm/traps activation
From: Julien Thierry <hidden>
Date: 2019-05-28 08:18:28
Also in:
kvm, kvmarm, lkml
Hi Sudeep, On 23/05/2019 11:34, Sudeep Holla wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel