KVM: Introduce kvm_unmap_hva_range() for kvm_mmu_notifier_invalidate_range_start()
When we tested KVM under memory pressure, with THP enabled on the host,
we noticed that MMU notifier took a long time to invalidate huge pages.
Since the invalidation was done with mmu_lock held, it not only wasted
the CPU but also made the host harder to respond.
This patch mitigates this by using kvm_handle_hva_range().
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 50ea12f..572ad01 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -52,6 +52,8 @@
struct kvm;
extern int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
+extern int kvm_unmap_hva_range(struct kvm *kvm,
+ unsigned long start, unsigned long end);
extern int kvm_age_hva(struct kvm *kvm, unsigned long hva);
extern int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
extern void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 1a470bc..3c635c0 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -870,6 +870,13 @@
return 0;
}
+int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+ if (kvm->arch.using_mmu_notifiers)
+ kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
+ return 0;
+}
+
static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long gfn)
{
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a3e9409..d4aab86 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -944,6 +944,7 @@
#define KVM_ARCH_WANT_MMU_NOTIFIER
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
+int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end);
int kvm_age_hva(struct kvm *kvm, unsigned long hva);
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 7235b0c..d2855f8 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1324,6 +1324,11 @@
return kvm_handle_hva(kvm, hva, 0, kvm_unmap_rmapp);
}
+int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+ return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp);
+}
+
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
kvm_handle_hva(kvm, hva, (unsigned long)&pte, kvm_set_pte_rmapp);