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    Subject[PART2 PATCH v6 11/12] svm: Introduce AMD IOMMU avic_ga_log_notifier
    Date
    This patch introduces avic_ga_log_notifier, which will be called
    by IOMMU driver whenever it handles the Guest vAPIC (GA) log entry.

    Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
    Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
    ---
    arch/x86/include/asm/kvm_host.h | 1 +
    arch/x86/kvm/svm.c | 73 +++++++++++++++++++++++++++++++++++++++--
    2 files changed, 72 insertions(+), 2 deletions(-)

    diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
    index 16b4d1d..a9466ad 100644
    --- a/arch/x86/include/asm/kvm_host.h
    +++ b/arch/x86/include/asm/kvm_host.h
    @@ -780,6 +780,7 @@ struct kvm_arch {
    u32 ldr_mode;
    struct page *avic_logical_id_table_page;
    struct page *avic_physical_id_table_page;
    + struct hlist_node hnode;
    };

    struct kvm_vm_stat {
    diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
    index 88acb41..c060e05 100644
    --- a/arch/x86/kvm/svm.c
    +++ b/arch/x86/kvm/svm.c
    @@ -34,6 +34,8 @@
    #include <linux/sched.h>
    #include <linux/trace_events.h>
    #include <linux/slab.h>
    +#include <linux/amd-iommu.h>
    +#include <linux/hashtable.h>

    #include <asm/apic.h>
    #include <asm/perf_event.h>
    @@ -945,6 +947,58 @@ static void svm_disable_lbrv(struct vcpu_svm *svm)
    set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 0, 0);
    }

    +/* Note:
    + * This hash table is used to map VM_ID to a struct kvm_arch,
    + * when handling AMD IOMMU GALOG notification to schedule in
    + * a particular vCPU.
    + */
    +#define SVM_VM_DATA_HASH_BITS 8
    +DECLARE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS);
    +static spinlock_t svm_vm_data_hash_lock;
    +
    +/* Note:
    + * This function is called from IOMMU driver to notify
    + * SVM to schedule in a particular vCPU of a particular VM.
    + */
    +static int avic_ga_log_notifier(u32 ga_tag)
    +{
    + unsigned long flags;
    + struct kvm_arch *ka = NULL;
    + struct kvm_vcpu *vcpu = NULL;
    + struct vcpu_svm *svm = NULL;
    + u32 vm_id = AVIC_GATAG_TO_VMID(ga_tag);
    + u32 vcpu_id = AVIC_GATAG_TO_VCPUID(ga_tag);
    +
    + pr_debug("SVM: %s: vm_id=%#x, vcpu_id=%#x\n", __func__, vm_id, vcpu_id);
    +
    + spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
    + hash_for_each_possible(svm_vm_data_hash, ka, hnode, vm_id) {
    + struct kvm *kvm = container_of(ka, struct kvm, arch);
    + struct kvm_arch *vm_data = &kvm->arch;
    +
    + if (vm_data->avic_vm_id != vm_id)
    + continue;
    + vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id);
    + break;
    + }
    + spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
    +
    + if (!vcpu)
    + return 0;
    +
    + svm = to_svm(vcpu);
    +
    + /* Note:
    + * At this point, the IOMMU should have already set the pending
    + * bit in the vAPIC backing page. So, we just need to schedule
    + * in the vcpu.
    + */
    + if (vcpu->mode == OUTSIDE_GUEST_MODE)
    + kvm_vcpu_wake_up(vcpu);
    +
    + return 0;
    +}
    +
    static __init int svm_hardware_setup(void)
    {
    int cpu;
    @@ -1003,10 +1057,15 @@ static __init int svm_hardware_setup(void)
    if (avic) {
    if (!npt_enabled ||
    !boot_cpu_has(X86_FEATURE_AVIC) ||
    - !IS_ENABLED(CONFIG_X86_LOCAL_APIC))
    + !IS_ENABLED(CONFIG_X86_LOCAL_APIC)) {
    avic = false;
    - else
    + } else {
    pr_info("AVIC enabled\n");
    +
    + hash_init(svm_vm_data_hash);
    + spin_lock_init(&svm_vm_data_hash_lock);
    + amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
    + }
    }

    return 0;
    @@ -1327,6 +1386,7 @@ static inline int avic_free_vm_id(int id)

    static void avic_vm_destroy(struct kvm *kvm)
    {
    + unsigned long flags;
    struct kvm_arch *vm_data = &kvm->arch;

    avic_free_vm_id(vm_data->avic_vm_id);
    @@ -1335,10 +1395,15 @@ static void avic_vm_destroy(struct kvm *kvm)
    __free_page(vm_data->avic_logical_id_table_page);
    if (vm_data->avic_physical_id_table_page)
    __free_page(vm_data->avic_physical_id_table_page);
    +
    + spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
    + hash_del(&vm_data->hnode);
    + spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
    }

    static int avic_vm_init(struct kvm *kvm)
    {
    + unsigned long flags;
    int err = -ENOMEM;
    struct kvm_arch *vm_data = &kvm->arch;
    struct page *p_page;
    @@ -1367,6 +1432,10 @@ static int avic_vm_init(struct kvm *kvm)
    vm_data->avic_logical_id_table_page = l_page;
    clear_page(page_address(l_page));

    + spin_lock_irqsave(&svm_vm_data_hash_lock, flags);
    + hash_add(svm_vm_data_hash, &vm_data->hnode, vm_data->avic_vm_id);
    + spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
    +
    return 0;

    free_avic:
    --
    1.9.1
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