Hi Radim, On 7/13/16 21:29, Radim Krčmář wrote:
2016-07-13 08:20-0500, Suravee Suthikulpanit:>From: Suravee Suthikulpanit<Suravee.Suthikulpanit@xxxxxxx> > >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@xxxxxxx> >--- > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/svm.c | 68 +++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 68 insertions(+), 2 deletions(-) > >diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >index 69e62862..a9466ad 100644 >--- a/arch/x86/include/asm/kvm_host.h >+++ b/arch/x86/include/asm/kvm_host.h >@@ -776,9 +776,11 @@ struct kvm_arch { > bool disabled_lapic_found; > > /* Struct members for AVIC */ >+ u32 avic_vm_id; > 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 16ef31b..1d9f2f6 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> >@@ -928,6 +930,53 @@ 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(int vm_id, int vcpu_id) >+{ >+ unsigned long flags; >+ struct kvm_arch *ka = NULL; >+ struct kvm_vcpu *vcpu = NULL; >+ struct vcpu_svm *svm = NULL; >+ >+ 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); >+ >+ vcpu = kvm_get_vcpu_by_id(kvm, vcpu_id);The first result is not neccessarily the correct one. With more than active 256 VMs, there is a guaranteed collision that cannot be disambiguated, so VCPUs in both VMs need to be woken up. Having a 24 bit vm_id and checking that kvm->*.avic_id & 0xfffff == vm_id would help a bit to avoid useless wakeups, but the collision cannot be avoided.
True. What if SVM guarantee that the VM_ID won't conflict b/w any two active VMs?
Thanks Suravee. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
