On Tue, Aug 8, 2023 at 11:09 PM Gavin Shan [off-list ref] wrote:

On 8/9/23 09:13, Raghavendra Rao Ananta wrote:

quoted

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 <redacted>
Reviewed-by: Gavin Shan <redacted>
Reviewed-by: Shaoqin Huang <redacted>
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;
  }

I guess @start_gfn can be renamed to @gfn, to be consistent with its declaration
in include/linux/kvm_host.h and struct kvm_x86_ops::flush_remote_tlbs_range()

Oh, yes. I'll consider this change for v9 (if there are enough changes
and we plan to push one).

Thank you.
Raghavendra

quoted

  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);

Thanks,
Gavin

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