linux-kernel - [PATCH v2 10/15] arm64: KVM: enable conditional save/restore full SPE profiling buffer controls

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Message-Id: <20190523103502.25925-11-sudeep.holla@arm.com>
Date:   Thu, 23 May 2019 11:34:57 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     kvmarm@...ts.cs.columbia.edu, linux-arm-kernel@...ts.infradead.org
Cc:     Sudeep Holla <sudeep.holla@....com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Christoffer Dall <christoffer.dall@....com>,
        Marc Zyngier <marc.zyngier@....com>,
        James Morse <james.morse@....com>,
        Suzuki K Pouloze <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Julien Thierry <julien.thierry@....com>
Subject: [PATCH v2 10/15] arm64: KVM: enable conditional save/restore full SPE profiling buffer controls

Now that we can save/restore the full SPE controls, we can enable it
if SPE is setup and ready to use in KVM. It's supported in KVM only if
all the CPUs in the system supports SPE.

However to support heterogenous systems, we need to move the check if
host supports SPE and do a partial save/restore.

Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 arch/arm64/kvm/hyp/debug-sr.c | 33 ++++++++++++++++-----------------
 include/kvm/arm_spe.h         |  3 +++
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c
index a4e6eaf5934f..cd0a7571abc1 100644
--- a/arch/arm64/kvm/hyp/debug-sr.c
+++ b/arch/arm64/kvm/hyp/debug-sr.c
@@ -67,18 +67,13 @@
 	}
 
 static void __hyp_text
-__debug_save_spe_nvhe(struct kvm_cpu_context *ctxt, bool full_ctxt)
+__debug_save_spe_context(struct kvm_cpu_context *ctxt, bool full_ctxt)
 {
 	u64 reg;
 
 	/* Clear pmscr in case of early return */
 	ctxt->sys_regs[PMSCR_EL1] = 0;
 
-	/* SPE present on this CPU? */
-	if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
-						  ID_AA64DFR0_PMSVER_SHIFT))
-		return;
-
 	/* Yes; is it owned by higher EL? */
 	reg = read_sysreg_s(SYS_PMBIDR_EL1);
 	if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT))
@@ -114,7 +109,7 @@ __debug_save_spe_nvhe(struct kvm_cpu_context *ctxt, bool full_ctxt)
 }
 
 static void __hyp_text
-__debug_restore_spe_nvhe(struct kvm_cpu_context *ctxt, bool full_ctxt)
+__debug_restore_spe_context(struct kvm_cpu_context *ctxt, bool full_ctxt)
 {
 	if (!ctxt->sys_regs[PMSCR_EL1])
 		return;
@@ -182,11 +177,14 @@ void __hyp_text __debug_restore_guest_context(struct kvm_vcpu *vcpu)
 	struct kvm_guest_debug_arch *host_dbg;
 	struct kvm_guest_debug_arch *guest_dbg;
 
+	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
+	guest_ctxt = &vcpu->arch.ctxt;
+
+	__debug_restore_spe_context(guest_ctxt, kvm_arm_spe_v1_ready(vcpu));
+
 	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
 
-	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
-	guest_ctxt = &vcpu->arch.ctxt;
 	host_dbg = &vcpu->arch.host_debug_state.regs;
 	guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr);
 
@@ -204,8 +202,7 @@ void __hyp_text __debug_restore_host_context(struct kvm_vcpu *vcpu)
 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 	guest_ctxt = &vcpu->arch.ctxt;
 
-	if (!has_vhe())
-		__debug_restore_spe_nvhe(host_ctxt, false);
+	__debug_restore_spe_context(host_ctxt, kvm_arm_spe_v1_ready(vcpu));
 
 	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
@@ -221,19 +218,21 @@ void __hyp_text __debug_restore_host_context(struct kvm_vcpu *vcpu)
 
 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.
-	 */
 	struct kvm_cpu_context *host_ctxt;
 
 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
-	if (!has_vhe())
-		__debug_save_spe_nvhe(host_ctxt, false);
+	if (cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
+						 ID_AA64DFR0_PMSVER_SHIFT))
+		__debug_save_spe_context(host_ctxt, kvm_arm_spe_v1_ready(vcpu));
 }
 
 void __hyp_text __debug_save_guest_context(struct kvm_vcpu *vcpu)
 {
+	bool kvm_spe_ready = kvm_arm_spe_v1_ready(vcpu);
+
+	/* SPE present on this vCPU? */
+	if (kvm_spe_ready)
+		__debug_save_spe_context(&vcpu->arch.ctxt, kvm_spe_ready);
 }
 
 u32 __hyp_text __kvm_get_mdcr_el2(void)
diff --git a/include/kvm/arm_spe.h b/include/kvm/arm_spe.h
index 2440ff02f747..fdcb0df1e0fd 100644
--- a/include/kvm/arm_spe.h
+++ b/include/kvm/arm_spe.h
@@ -18,6 +18,8 @@ struct kvm_spe {
 
 #ifdef CONFIG_KVM_ARM_SPE
 
+#define kvm_arm_spe_v1_ready(v)		((v)->arch.spe.ready)
+
 static inline bool kvm_arm_support_spe_v1(void)
 {
 	u64 dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1);
@@ -27,6 +29,7 @@ static inline bool kvm_arm_support_spe_v1(void)
 }
 #else
 
+#define kvm_arm_spe_v1_ready(v)		(false)
 #define kvm_arm_support_spe_v1()	(false)
 #endif /* CONFIG_KVM_ARM_SPE */
 
-- 
2.17.1