[PATCH v12 11/84] KVM: Rename gfn_to_page_many_atomic() to kvm_prefetch_pages()

Sean Christopherson
2024-07-26T23:57:48Z

Rename gfn_to_page_many_atomic() to kvm_prefetch_pages() to try and
communicate its true purpose, as the "atomic" aspect is essentially a
side effect of the fact that x86 uses the API while holding mmu_lock.
E.g. even if mmu_lock weren't held, KVM wouldn't want to fault-in pages,
as the goal is to opportunistically grab surrounding pages that have
already been accessed and/or dirtied by the host, and to do so quickly.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 2 +-
arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
include/linux/kvm_host.h | 4 ++--
virt/kvm/kvm_main.c | 6 +++---
4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b7642f1f993f..c1914f02c5e1 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2912,7 +2912,7 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
if (!slot)
return -1;

- ret = gfn_to_page_many_atomic(slot, gfn, pages, end - start);
+ ret = kvm_prefetch_pages(slot, gfn, pages, end - start);
if (ret <= 0)
return -1;

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 6b215a932158..bc801d454f41 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -549,7 +549,7 @@ FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
if (!slot)
return false;

- if (gfn_to_page_many_atomic(slot, gfn, &page, 1) != 1)
+ if (kvm_prefetch_pages(slot, gfn, &page, 1) != 1)
return false;

mmu_set_spte(vcpu, slot, spte, pte_access, gfn, page_to_pfn(page), NULL);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c5d39a337aa3..79fed9fea638 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1192,8 +1192,8 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm);
void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot);

-int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
- struct page **pages, int nr_pages);
+int kvm_prefetch_pages(struct kvm_memory_slot *slot, gfn_t gfn,
+ struct page **pages, int nr_pages);

struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 656e931ac39e..803299778cf8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3060,8 +3060,8 @@ kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn);

-int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
- struct page **pages, int nr_pages)
+int kvm_prefetch_pages(struct kvm_memory_slot *slot, gfn_t gfn,
+ struct page **pages, int nr_pages)
{
unsigned long addr;
gfn_t entry = 0;
@@ -3075,7 +3075,7 @@ int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,

return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages);
}
-EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
+EXPORT_SYMBOL_GPL(kvm_prefetch_pages);

/*
* Do not use this helper unless you are absolutely certain the gfn _must_ be