Patchwork [07/13] arm64: KVM: split debug save restore across vm/traps activation

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Submitter Sudeep Holla
Date Feb. 28, 2019, 4:07 p.m.
Message ID <20190228160737.3323-8-sudeep.holla@arm.com>
Download mbox | patch
Permalink /patch/738325/
State New
Headers show

Comments

Sudeep Holla - Feb. 28, 2019, 4:07 p.m.
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.holla@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(-)

Patch

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index a4a6f6deef89..0deea8c75f77 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -163,8 +163,10 @@  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)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
@@ -199,6 +192,20 @@  void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu)
 	vcpu->arch.flags &= ~KVM_ARM64_DEBUG_DIRTY;
 }
 
+void __hyp_text __debug_save_host_context(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * 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);
+}
+
+void __hyp_text __debug_save_guest_context(struct kvm_vcpu *vcpu)
+{
+}
+
 u32 __hyp_text __kvm_get_mdcr_el2(void)
 {
 	return read_sysreg(mdcr_el2);
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 08e2a01188ac..3054b8b8f037 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -472,6 +472,7 @@  int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 	guest_ctxt = &vcpu->arch.ctxt;
 
 	sysreg_save_host_state_vhe(host_ctxt);
+	__debug_save_host_context(vcpu);
 
 	/*
 	 * ARM erratum 1165522 requires us to configure both stage 1 and
@@ -488,7 +489,7 @@  int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 	__activate_traps(vcpu);
 
 	sysreg_restore_guest_state_vhe(guest_ctxt);
-	__debug_switch_to_guest(vcpu);
+	__debug_restore_guest_context(vcpu);
 
 	__set_guest_arch_workaround_state(vcpu);
 
@@ -502,6 +503,7 @@  int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 	__set_host_arch_workaround_state(vcpu);
 
 	sysreg_save_guest_state_vhe(guest_ctxt);
+	__debug_save_guest_context(vcpu);
 
 	__deactivate_traps(vcpu);
 
@@ -510,7 +512,7 @@  int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
 		__fpsimd_save_fpexc32(vcpu);
 
-	__debug_switch_to_host(vcpu);
+	__debug_restore_host_context(vcpu);
 
 	return exit_code;
 }
@@ -530,6 +532,7 @@  int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 	guest_ctxt = &vcpu->arch.ctxt;
 
 	__sysreg_save_state_nvhe(host_ctxt);
+	__debug_save_host_context(vcpu);
 
 	__activate_vm(kern_hyp_va(vcpu->kvm));
 	__activate_traps(vcpu);
@@ -543,7 +546,7 @@  int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 	 */
 	__sysreg32_restore_state(vcpu);
 	__sysreg_restore_state_nvhe(guest_ctxt);
-	__debug_switch_to_guest(vcpu);
+	__debug_restore_guest_context(vcpu);
 
 	__set_guest_arch_workaround_state(vcpu);
 
@@ -557,6 +560,7 @@  int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 	__set_host_arch_workaround_state(vcpu);
 
 	__sysreg_save_state_nvhe(guest_ctxt);
+	__debug_save_guest_context(vcpu);
 	__sysreg32_save_state(vcpu);
 	__timer_disable_traps(vcpu);
 	__hyp_vgic_save_state(vcpu);
@@ -573,7 +577,7 @@  int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
 	 * This must come after restoring the host sysregs, since a non-VHE
 	 * system may enable SPE here and make use of the TTBRs.
 	 */
-	__debug_switch_to_host(vcpu);
+	__debug_restore_host_context(vcpu);
 
 	return exit_code;
 }