linux-kernel - [RFC PATCH 17/26] kvm: arm64: Bootstrap PSCI power state of host CPUs

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Message-Id: <20201104183630.27513-18-dbrazdil@google.com>
Date:   Wed,  4 Nov 2020 18:36:21 +0000
From:   David Brazdil <dbrazdil@...gle.com>
To:     kvmarm@...ts.cs.columbia.edu
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Dennis Zhou <dennis@...nel.org>,
        Tejun Heo <tj@...nel.org>, Christoph Lameter <cl@...ux.com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Quentin Perret <qperret@...gle.com>,
        Andrew Scull <ascull@...gle.com>, kernel-team@...roid.com,
        David Brazdil <dbrazdil@...gle.com>
Subject: [RFC PATCH 17/26] kvm: arm64: Bootstrap PSCI power state of host CPUs

Proxying host's PSCI SMCs will require synchronizing CPU_ON/OFF/SUSPEND
calls based on the observed state of individual cores. Add a per-CPU enum
that tracks the power state of each core and initialize all CPUs online
at the point of KVM init to ON.

Signed-off-by: David Brazdil <dbrazdil@...gle.com>
---
 arch/arm64/include/asm/kvm_asm.h | 6 ++++++
 arch/arm64/include/asm/kvm_hyp.h | 1 +
 arch/arm64/kvm/arm.c             | 5 +++++
 arch/arm64/kvm/hyp/nvhe/psci.c   | 2 ++
 4 files changed, 14 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 893327d1e449..9eecb37db6df 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -157,6 +157,12 @@ struct kvm_nvhe_init_params {
 	unsigned long vector_ptr;
 };
 
+enum kvm_nvhe_psci_state {
+	KVM_NVHE_PSCI_CPU_OFF = 0,
+	KVM_NVHE_PSCI_CPU_PENDING_ON,
+	KVM_NVHE_PSCI_CPU_ON,
+};
+
 /* Translate a kernel address @ptr into its equivalent linear mapping */
 #define kvm_ksym_ref(ptr)						\
 	({								\
diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 95a2bbbcc7e1..cf4c1d16c3e0 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -97,6 +97,7 @@ void deactivate_traps_vhe_put(void);
 u64 __guest_enter(struct kvm_vcpu *vcpu);
 
 #ifdef __KVM_NVHE_HYPERVISOR__
+void kvm_host_psci_cpu_init(void);
 bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt);
 #endif
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 580d4a656a7b..5b073806463e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -52,6 +52,7 @@ DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
 DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
+DECLARE_KVM_NVHE_PER_CPU(enum kvm_nvhe_psci_state, psci_cpu_state);
 
 /* The VMID used in the VTTBR */
 static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
@@ -1517,10 +1518,14 @@ static void init_psci(void)
 {
 	extern u32 kvm_nvhe_sym(kvm_host_psci_version);
 	extern u32 kvm_nvhe_sym(kvm_host_psci_function_id)[PSCI_FN_MAX];
+	int cpu;
 
 	kvm_nvhe_sym(kvm_host_psci_version) = psci_driver_version;
 	memcpy(kvm_nvhe_sym(kvm_host_psci_function_id),
 		psci_function_id, sizeof(psci_function_id));
+
+	for_each_online_cpu(cpu)
+		*per_cpu_ptr_nvhe_sym(psci_cpu_state, cpu) = KVM_NVHE_PSCI_CPU_ON;
 }
 
 static int init_common_resources(void)
diff --git a/arch/arm64/kvm/hyp/nvhe/psci.c b/arch/arm64/kvm/hyp/nvhe/psci.c
index 3eafcf48a29b..c3d0a6246c66 100644
--- a/arch/arm64/kvm/hyp/nvhe/psci.c
+++ b/arch/arm64/kvm/hyp/nvhe/psci.c
@@ -20,6 +20,8 @@ s64 hyp_physvirt_offset;
 
 #define __hyp_pa(x) ((phys_addr_t)(x) + hyp_physvirt_offset)
 
+DEFINE_PER_CPU(enum kvm_nvhe_psci_state, psci_cpu_state);
+
 static u64 get_psci_func_id(struct kvm_cpu_context *host_ctxt)
 {
 	return host_ctxt->regs.regs[0];
-- 
2.29.1.341.ge80a0c044ae-goog