linux-kernel - [PATCH 4.14 71/92] KVM: arm/arm64: Convert kvm_host_cpu

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Date:   Fri, 20 Jul 2018 14:14:15 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        James Morse <james.morse@....com>,
        Christoffer Dall <cdall@...aro.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Marc Zyngier <marc.zyngier@....com>
Subject: [PATCH 4.14 71/92] KVM: arm/arm64: Convert kvm_host_cpu_state to a static per-cpu allocation

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Morse <james.morse@....com>

Commit 36989e7fd386a9a5822c48691473863f8fbb404d upstream.

kvm_host_cpu_state is a per-cpu allocation made from kvm_arch_init()
used to store the host EL1 registers when KVM switches to a guest.

Make it easier for ASM to generate pointers into this per-cpu memory
by making it a static allocation.

Signed-off-by: James Morse <james.morse@....com>
Acked-by: Christoffer Dall <cdall@...aro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 virt/kvm/arm/arm.c |   18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -51,8 +51,8 @@
 __asm__(".arch_extension	virt");
 #endif
 
+DEFINE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
-static kvm_cpu_context_t __percpu *kvm_host_cpu_state;
 
 /* Per-CPU variable containing the currently running vcpu. */
 static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
@@ -351,7 +351,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu
 	}
 
 	vcpu->cpu = cpu;
-	vcpu->arch.host_cpu_context = this_cpu_ptr(kvm_host_cpu_state);
+	vcpu->arch.host_cpu_context = this_cpu_ptr(&kvm_host_cpu_state);
 
 	kvm_arm_set_running_vcpu(vcpu);
 
@@ -1259,19 +1259,8 @@ static inline void hyp_cpu_pm_exit(void)
 }
 #endif
 
-static void teardown_common_resources(void)
-{
-	free_percpu(kvm_host_cpu_state);
-}
-
 static int init_common_resources(void)
 {
-	kvm_host_cpu_state = alloc_percpu(kvm_cpu_context_t);
-	if (!kvm_host_cpu_state) {
-		kvm_err("Cannot allocate host CPU state\n");
-		return -ENOMEM;
-	}
-
 	/* set size of VMID supported by CPU */
 	kvm_vmid_bits = kvm_get_vmid_bits();
 	kvm_info("%d-bit VMID\n", kvm_vmid_bits);
@@ -1413,7 +1402,7 @@ static int init_hyp_mode(void)
 	for_each_possible_cpu(cpu) {
 		kvm_cpu_context_t *cpu_ctxt;
 
-		cpu_ctxt = per_cpu_ptr(kvm_host_cpu_state, cpu);
+		cpu_ctxt = per_cpu_ptr(&kvm_host_cpu_state, cpu);
 		err = create_hyp_mappings(cpu_ctxt, cpu_ctxt + 1, PAGE_HYP);
 
 		if (err) {
@@ -1497,7 +1486,6 @@ out_hyp:
 	if (!in_hyp_mode)
 		teardown_hyp_mode();
 out_err:
-	teardown_common_resources();
 	return err;
 }