This patch is to provide a way for platforms to register tlb remote flush
callback and this helps to optimize operation of tlb flush among vcpus for
nested virtualization case.
Signed-off-by: Lan Tianyu <Tianyu.Lan@xxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 12 +++++++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0ebe659f2802..aaad43916f9d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -973,6 +973,7 @@ struct kvm_x86_ops {
void (*set_rflags)(struct kvm_vcpu *vcpu, unsigned long rflags);
void (*tlb_flush)(struct kvm_vcpu *vcpu, bool invalidate_gpa);
+ int (*tlb_remote_flush)(struct kvm *kvm);
void (*run)(struct kvm_vcpu *vcpu);
int (*handle_exit)(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c5f6a552e486..31e2b54c6049 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -251,11 +251,21 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
+ long dirty_count;
+
+ /*
+ * Call tlb_remote_flush first and go back old way when
+ * return failure.
+ */
+ if (kvm_x86_ops->tlb_remote_flush &&
+ !kvm_x86_ops->tlb_remote_flush(kvm))
+ return;
+
/*
* Read tlbs_dirty before setting KVM_REQ_TLB_FLUSH in
* kvm_make_all_cpus_request.
*/
- long dirty_count = smp_load_acquire(&kvm->tlbs_dirty);
+ dirty_count = smp_load_acquire(&kvm->tlbs_dirty);
/*
* We want to publish modifications to the page tables before reading
--
2.14.3
