[PATCH v8 05/14] KVM: Allow range-based TLB invalidation from common code

Raghavendra Rao Ananta
2023-08-08T23:13:59Z

From: David Matlack <dmatlack@google.com>

Make kvm_flush_remote_tlbs_range() visible in common code and create a
default implementation that just invalidates the whole TLB.

This paves the way for several future features/cleanups:

- Introduction of range-based TLBI on ARM.
- Eliminating kvm_arch_flush_remote_tlbs_memslot()
- Moving the KVM/x86 TDP MMU to common code.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
---
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/mmu/mmu.c | 8 ++++----
arch/x86/kvm/mmu/mmu_internal.h | 3 ---
include/linux/kvm_host.h | 12 ++++++++++++
virt/kvm/kvm_main.c | 13 +++++++++++++
5 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a2d3cfc2eb75c..b547d17c58f63 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1804,6 +1804,8 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
return -ENOTSUPP;
}

+#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
+
#define kvm_arch_pmi_in_guest(vcpu) \
((vcpu) && (vcpu)->arch.handling_intr_from_guest)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ec169f5c7dce2..6adbe6c870982 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -278,16 +278,16 @@ static inline bool kvm_available_flush_remote_tlbs_range(void)
return kvm_x86_ops.flush_remote_tlbs_range;
}

-void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
- gfn_t nr_pages)
+int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
+ u64 nr_pages)
{
int ret = -EOPNOTSUPP;

if (kvm_x86_ops.flush_remote_tlbs_range)
ret = static_call(kvm_x86_flush_remote_tlbs_range)(kvm, start_gfn,
nr_pages);
- if (ret)
- kvm_flush_remote_tlbs(kvm);
+
+ return ret;
}

static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index);
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index d39af5639ce97..86cb83bb34804 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -170,9 +170,6 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
struct kvm_memory_slot *slot, u64 gfn,
int min_level);

-void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
- gfn_t nr_pages);
-
/* Flush the given page (huge or not) of guest memory. */
static inline void kvm_flush_remote_tlbs_gfn(struct kvm *kvm, gfn_t gfn, int level)
{
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ade5d4500c2ce..f0be5d9c37dd1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1359,6 +1359,7 @@ int kvm_vcpu_yield_to(struct kvm_vcpu *target);
void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool yield_to_kernel_mode);

void kvm_flush_remote_tlbs(struct kvm *kvm);
+void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages);

#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min);
@@ -1488,6 +1489,17 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
int kvm_arch_flush_remote_tlbs(struct kvm *kvm);
#endif

+#ifndef __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
+static inline int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
+ gfn_t gfn, u64 nr_pages)
+{
+ return -EOPNOTSUPP;
+}
+#else
+int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
+ gfn_t gfn, u64 nr_pages);
+#endif
+
#ifdef __KVM_HAVE_ARCH_NONCOHERENT_DMA
void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d6b0507861550..26e91000f579d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -366,6 +366,19 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
}
EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);

+void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
+{
+ if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages))
+ return;
+
+ /*
+ * Fall back to a flushing entire TLBs if the architecture range-based
+ * TLB invalidation is unsupported or can't be performed for whatever
+ * reason.
+ */
+ kvm_flush_remote_tlbs(kvm);
+}
+
static void kvm_flush_shadow_all(struct kvm *kvm)
{
kvm_arch_flush_shadow_all(kvm);
--
2.41.0.640.ga95def55d0-goog