[PATCH 08/12] KVM: remove kvm_arch_gmem_prepare_needed()

Paolo Bonzini
2024-07-11T22:28:07Z

It is enough to return 0 if a guest need not do any preparation.
This is in fact how sev_gmem_prepare() works for non-SNP guests,
and it extends naturally to Intel hosts: the x86 callback for
gmem_prepare is optional and returns 0 if not defined.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/x86.c | 5 -----
include/linux/kvm_host.h | 1 -
virt/kvm/guest_memfd.c | 13 +++----------
3 files changed, 3 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a1c85591f92c..4f58423c6148 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13604,11 +13604,6 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu)
EXPORT_SYMBOL_GPL(kvm_arch_no_poll);

#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE
-bool kvm_arch_gmem_prepare_needed(struct kvm *kvm)
-{
- return kvm->arch.vm_type == KVM_X86_SNP_VM;
-}
-
int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order)
{
return static_call(kvm_x86_gmem_prepare)(kvm, pfn, gfn, max_order);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index eb8404e9aa03..f6e11991442d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2443,7 +2443,6 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,

#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE
int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order);
-bool kvm_arch_gmem_prepare_needed(struct kvm *kvm);
#endif

/**
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index f4d82719ec19..509360eefea5 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -29,16 +29,9 @@ static int __kvm_gmem_prepare_folio(struct kvm *kvm, struct kvm_memory_slot *slo
pgoff_t index, struct folio *folio)
{
#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE
- kvm_pfn_t pfn;
- gfn_t gfn;
- int rc;
-
- if (!kvm_arch_gmem_prepare_needed(kvm))
- return 0;
-
- pfn = folio_file_pfn(folio, index);
- gfn = slot->base_gfn + index - slot->gmem.pgoff;
- rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, folio_order(folio));
+ kvm_pfn_t pfn = folio_file_pfn(folio, index);
+ gfn_t gfn = slot->base_gfn + index - slot->gmem.pgoff;
+ int rc = kvm_arch_gmem_prepare(kvm, gfn, pfn, folio_order(folio));
if (rc) {
pr_warn_ratelimited("gmem: Failed to prepare folio for index %lx GFN %llx PFN %llx error %d.\n",
index, gfn, pfn, rc);
--
2.43.0