lkml.org 
[lkml]   [2022]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v5 19/30] KVM: kvm_arch.c: Remove a global variable, hardware_enable_failed
    Date
    From: Isaku Yamahata <isaku.yamahata@intel.com>

    A global variable hardware_enable_failed in kvm_arch.c is used only by
    kvm_arch_add_vm() and hardware_enable(). It doesn't have to be a global
    variable. Make it function local.

    Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
    ---
    virt/kvm/kvm_arch.c | 61 ++++++++++++++++++++++-----------------------
    1 file changed, 30 insertions(+), 31 deletions(-)

    diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c
    index e6bf9de18cba..10fd29bdd6e1 100644
    --- a/virt/kvm/kvm_arch.c
    +++ b/virt/kvm/kvm_arch.c
    @@ -13,7 +13,6 @@
    #include <linux/kvm_host.h>

    static cpumask_t cpus_hardware_enabled = CPU_MASK_NONE;
    -static atomic_t hardware_enable_failed;

    /*
    * Called after the VM is otherwise initialized, but just before adding it to
    @@ -24,7 +23,7 @@ int __weak kvm_arch_post_init_vm(struct kvm *kvm)
    return 0;
    }

    -static void hardware_enable(void *junk)
    +static int __hardware_enable(void)
    {
    int cpu = raw_smp_processor_id();
    int r;
    @@ -32,18 +31,22 @@ static void hardware_enable(void *junk)
    WARN_ON_ONCE(preemptible());

    if (cpumask_test_cpu(cpu, &cpus_hardware_enabled))
    - return;
    -
    - cpumask_set_cpu(cpu, &cpus_hardware_enabled);
    -
    + return 0;
    r = kvm_arch_hardware_enable();
    -
    - if (r) {
    - cpumask_clear_cpu(cpu, &cpus_hardware_enabled);
    - atomic_inc(&hardware_enable_failed);
    + if (r)
    pr_warn("kvm: enabling virtualization on CPU%d failed during %pSb\n",
    cpu, __builtin_return_address(0));
    - }
    + else
    + cpumask_set_cpu(cpu, &cpus_hardware_enabled);
    + return r;
    +}
    +
    +static void hardware_enable(void *arg)
    +{
    + atomic_t *failed = arg;
    +
    + if (__hardware_enable())
    + atomic_inc(failed);
    }

    static void hardware_disable(void *junk)
    @@ -64,15 +67,15 @@ static void hardware_disable(void *junk)
    */
    int __weak kvm_arch_add_vm(struct kvm *kvm, int usage_count)
    {
    + atomic_t failed = ATOMIC_INIT(0);
    int r = 0;

    if (usage_count != 1)
    return 0;

    - atomic_set(&hardware_enable_failed, 0);
    - on_each_cpu(hardware_enable, NULL, 1);
    + on_each_cpu(hardware_enable, &failed, 1);

    - if (atomic_read(&hardware_enable_failed)) {
    + if (atomic_read(&failed)) {
    r = -EBUSY;
    goto err;
    }
    @@ -95,33 +98,29 @@ int __weak kvm_arch_del_vm(int usage_count)

    int __weak kvm_arch_online_cpu(unsigned int cpu, int usage_count)
    {
    - int ret = 0;
    + int ret;

    ret = kvm_arch_check_processor_compat();
    if (ret)
    return ret;

    + if (!usage_count)
    + return 0;
    +
    + /*
    + * arch callback kvm_arch_hardware_enable() assumes that
    + * preemption is disabled for historical reason. Disable
    + * preemption until all arch callbacks are fixed.
    + */
    + preempt_disable();
    /*
    * Abort the CPU online process if hardware virtualization cannot
    * be enabled. Otherwise running VMs would encounter unrecoverable
    * errors when scheduled to this CPU.
    */
    - if (usage_count) {
    - WARN_ON_ONCE(atomic_read(&hardware_enable_failed));
    + ret = __hardware_enable();
    + preempt_enable();

    - /*
    - * arch callback kvm_arch_hardware_eanble() assumes that
    - * preemption is disabled for historical reason. Disable
    - * preemption until all arch callbacks are fixed.
    - */
    - preempt_disable();
    - hardware_enable(NULL);
    - preempt_enable();
    - if (atomic_read(&hardware_enable_failed)) {
    - atomic_set(&hardware_enable_failed, 0);
    - ret = -EIO;
    - }
    - }
    return ret;
    }

    @@ -160,5 +159,5 @@ int __weak kvm_arch_suspend(int usage_count)
    void __weak kvm_arch_resume(int usage_count)
    {
    if (usage_count)
    - hardware_enable(NULL);
    + (void)__hardware_enable();
    }
    --
    2.25.1
    \
     
     \ /
      Last update: 2022-09-22 20:26    [W:3.875 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site