linux-kernel - [PATCH v2 1/2] KVM: Introduce pv check helpers

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Date:   Mon, 10 Feb 2020 14:37:30 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>
Subject: [PATCH v2 1/2] KVM: Introduce pv check helpers

From: Wanpeng Li <wanpengli@...cent.com>

Introduce some pv check helpers for consistency.

Suggested-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
---
 arch/x86/kernel/kvm.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index d817f25..76ea8c4 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -425,7 +425,27 @@ static void __init sev_map_percpu_data(void)
     }
 }

+static bool pv_tlb_flush_supported(void)
+{
+    return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+        !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
+        kvm_para_has_feature(KVM_FEATURE_STEAL_TIME));
+}
+
 #ifdef CONFIG_SMP
+
+static bool pv_ipi_supported(void)
+{
+    return kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI);
+}
+
+static bool pv_sched_yield_supported(void)
+{
+    return (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
+        !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
+        kvm_para_has_feature(KVM_FEATURE_STEAL_TIME));
+}
+
 #define KVM_IPI_CLUSTER_SIZE    (2 * BITS_PER_LONG)

 static void __send_ipi_mask(const struct cpumask *mask, int vector)
@@ -619,9 +639,7 @@ static void __init kvm_guest_init(void)
         pv_ops.time.steal_clock = kvm_steal_clock;
     }

-    if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
-        !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
-        kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+    if (pv_tlb_flush_supported()) {
         pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others;
         pv_ops.mmu.tlb_remove_table = tlb_remove_table;
     }
@@ -632,9 +650,7 @@ static void __init kvm_guest_init(void)
 #ifdef CONFIG_SMP
     smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;
     smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
-    if (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
-        !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
-        kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+    if (pv_sched_yield_supported()) {
         smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi;
         pr_info("KVM setup pv sched yield\n");
     }
@@ -700,7 +716,7 @@ static uint32_t __init kvm_detect(void)
 static void __init kvm_apic_init(void)
 {
 #if defined(CONFIG_SMP)
-    if (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI))
+    if (pv_ipi_supported())
         kvm_setup_pv_ipi();
 #endif
 }
@@ -739,9 +755,7 @@ static __init int kvm_setup_pv_tlb_flush(void)
     if (!kvm_para_available() || nopv)
         return 0;

-    if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
-        !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
-        kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+    if (pv_tlb_flush_supported()) {
         for_each_possible_cpu(cpu) {
             zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, cpu),
                 GFP_KERNEL, cpu_to_node(cpu));
--
2.7.4