[PATCH 09/16] KVM: x86/mmu: Make kvm_tdp_mmu_alloc_root() return void

Rick Edgecombe
2024-05-15T01:00:09Z

The kvm_tdp_mmu_alloc_root() function currently always returns 0. This
allows for the caller, mmu_alloc_direct_roots(), to call
kvm_tdp_mmu_alloc_root() and also return 0 in one line:
return kvm_tdp_mmu_alloc_root(vcpu);

So it is useful even though the return value of kvm_tdp_mmu_alloc_root()
is always the same. However, in future changes, kvm_tdp_mmu_alloc_root()
will be called twice in mmu_alloc_direct_roots(). This will force the
first call to either awkwardly handle the return value that will always
be zero or ignore it. So change kvm_tdp_mmu_alloc_root() to return void.
Do it in a separate change so the future change will be cleaner.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
TDX MMU Part 1:
- New patch
---
arch/x86/kvm/mmu/mmu.c | 6 ++++--
arch/x86/kvm/mmu/tdp_mmu.c | 3 +--
arch/x86/kvm/mmu/tdp_mmu.h | 2 +-
3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 808805b3478d..76f92cb37a96 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3700,8 +3700,10 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
unsigned i;
int r;

- if (tdp_mmu_enabled)
- return kvm_tdp_mmu_alloc_root(vcpu);
+ if (tdp_mmu_enabled) {
+ kvm_tdp_mmu_alloc_root(vcpu);
+ return 0;
+ }

write_lock(&vcpu->kvm->mmu_lock);
r = make_mmu_pages_available(vcpu);
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 6fa910b017d1..0d6d96d86703 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -224,7 +224,7 @@ static void tdp_mmu_init_child_sp(struct kvm_mmu_page *child_sp,
tdp_mmu_init_sp(child_sp, iter->sptep, iter->gfn, role);
}

-int kvm_tdp_mmu_alloc_root(struct kvm_vcpu *vcpu)
+void kvm_tdp_mmu_alloc_root(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *mmu = vcpu->arch.mmu;
union kvm_mmu_page_role role = mmu->root_role;
@@ -285,7 +285,6 @@ int kvm_tdp_mmu_alloc_root(struct kvm_vcpu *vcpu)
*/
mmu->root.hpa = __pa(root->spt);
mmu->root.pgd = 0;
- return 0;
}

static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index 58b55e61bd33..437ddd4937a9 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -10,7 +10,7 @@
void kvm_mmu_init_tdp_mmu(struct kvm *kvm);
void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm);

-int kvm_tdp_mmu_alloc_root(struct kvm_vcpu *vcpu);
+void kvm_tdp_mmu_alloc_root(struct kvm_vcpu *vcpu);

__must_check static inline bool kvm_tdp_mmu_get_root(struct kvm_mmu_page *root)
{
--
2.34.1