[PART2 PATCH v5 11/12] svm: Introduce AMD IOMMU avic_ga_log_notifier

Suravee Suthikulpanit
2016-07-25T09:34:44Z

From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>

This patch introduces avic_ga_log_notifier, which will be called
by IOMMU driver whenever it handles the Guest vAPIC (GA) log entry.

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 90dc0fb..2be5ed7 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>
@@ -944,6 +946,58 @@ 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;
@@ -1002,10 +1056,15 @@ 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;
@@ -1347,6 +1406,7 @@ 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);
@@ -1355,10 +1415,15 @@ 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;
@@ -1387,6 +1452,10 @@ 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