[PATCH v4 03/11] KVM: x86/mmu: Grab mmu_invalidate_seq in kvm_faultin_pfn()

Sean Christopherson
2022-10-12T18:18:10Z

From: David Matlack <dmatlack@google.com>

Grab mmu_invalidate_seq in kvm_faultin_pfn() and stash it in struct
kvm_page_fault. The eliminates duplicate code and reduces the amount of
parameters needed for is_page_fault_stale().

Preemptively split out __kvm_faultin_pfn() to a separate function for
use in subsequent commits.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 21 ++++++++++++---------
arch/x86/kvm/mmu/mmu_internal.h | 1 +
arch/x86/kvm/mmu/paging_tmpl.h | 6 +-----
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b2b970e9fa8d..72c3dc1884f6 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4143,7 +4143,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true);
}

-static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
{
struct kvm_memory_slot *slot = fault->slot;
bool async;
@@ -4199,12 +4199,20 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
return RET_PF_CONTINUE;
}

+static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+ fault->mmu_seq = vcpu->kvm->mmu_invalidate_seq;
+ smp_rmb();
+
+ return __kvm_faultin_pfn(vcpu, fault);
+}
+
/*
* Returns true if the page fault is stale and needs to be retried, i.e. if the
* root was invalidated by a memslot update or a relevant mmu_notifier fired.
*/
static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
- struct kvm_page_fault *fault, int mmu_seq)
+ struct kvm_page_fault *fault)
{
struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root.hpa);

@@ -4224,14 +4232,12 @@ static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
return true;

return fault->slot &&
- mmu_invalidate_retry_hva(vcpu->kvm, mmu_seq, fault->hva);
+ mmu_invalidate_retry_hva(vcpu->kvm, fault->mmu_seq, fault->hva);
}

static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
{
bool is_tdp_mmu_fault = is_tdp_mmu(vcpu->arch.mmu);
-
- unsigned long mmu_seq;
int r;

fault->gfn = fault->addr >> PAGE_SHIFT;
@@ -4248,9 +4254,6 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
if (r)
return r;

- mmu_seq = vcpu->kvm->mmu_invalidate_seq;
- smp_rmb();
-
r = kvm_faultin_pfn(vcpu, fault);
if (r != RET_PF_CONTINUE)
return r;
@@ -4266,7 +4269,7 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
else
write_lock(&vcpu->kvm->mmu_lock);

- if (is_page_fault_stale(vcpu, fault, mmu_seq))
+ if (is_page_fault_stale(vcpu, fault))
goto out_unlock;

r = make_mmu_pages_available(vcpu);
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 582def531d4d..1c0a1e7c796d 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -221,6 +221,7 @@ struct kvm_page_fault {
struct kvm_memory_slot *slot;

/* Outputs of kvm_faultin_pfn. */
+ unsigned long mmu_seq;
kvm_pfn_t pfn;
hva_t hva;
bool map_writable;
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 5ab5f94dcb6f..30b9d9b6734f 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -791,7 +791,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
{
struct guest_walker walker;
int r;
- unsigned long mmu_seq;
bool is_self_change_mapping;

pgprintk("%s: addr %lx err %x\n", __func__, fault->addr, fault->error_code);
@@ -838,9 +837,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
else
fault->max_level = walker.level;

- mmu_seq = vcpu->kvm->mmu_invalidate_seq;
- smp_rmb();
-
r = kvm_faultin_pfn(vcpu, fault);
if (r != RET_PF_CONTINUE)
return r;
@@ -871,7 +867,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
r = RET_PF_RETRY;
write_lock(&vcpu->kvm->mmu_lock);

- if (is_page_fault_stale(vcpu, fault, mmu_seq))
+ if (is_page_fault_stale(vcpu, fault))
goto out_unlock;

r = make_mmu_pages_available(vcpu);