Re: [RFC PATCH 3/8] KVM: x86/mmu: Introduce initialier macro for struct kvm_page_fault

Isaku Yamahata
2024-03-11T22:56:12Z

On Mon, Mar 11, 2024 at 10:24:50AM -0700,
Sean Christopherson <seanjc@google.com> wrote:

> On Fri, Mar 01, 2024, isaku.yamahata@intel.com wrote:
> > From: Isaku Yamahata <isaku.yamahata@intel.com>
> >
> > Another function will initialize struct kvm_page_fault. Add initializer
> > macro to unify the big struct initialization.
> >
> > No functional change intended.
> >
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > ---
> > arch/x86/kvm/mmu/mmu_internal.h | 44 +++++++++++++++++++--------------
> > 1 file changed, 26 insertions(+), 18 deletions(-)
> >
> > diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
> > index 0669a8a668ca..72ef09fc9322 100644
> > --- a/arch/x86/kvm/mmu/mmu_internal.h
> > +++ b/arch/x86/kvm/mmu/mmu_internal.h
> > @@ -279,27 +279,35 @@ enum {
> > RET_PF_SPURIOUS,
> > };
> >
> > +#define KVM_PAGE_FAULT_INIT(_vcpu, _cr2_or_gpa, _err, _prefetch, _max_level) { \
> > + .addr = (_cr2_or_gpa), \
> > + .error_code = (_err), \
> > + .exec = (_err) & PFERR_FETCH_MASK, \
> > + .write = (_err) & PFERR_WRITE_MASK, \
> > + .present = (_err) & PFERR_PRESENT_MASK, \
> > + .rsvd = (_err) & PFERR_RSVD_MASK, \
> > + .user = (_err) & PFERR_USER_MASK, \
> > + .prefetch = (_prefetch), \
> > + .is_tdp = \
> > + likely((_vcpu)->arch.mmu->page_fault == kvm_tdp_page_fault), \
> > + .nx_huge_page_workaround_enabled = \
> > + is_nx_huge_page_enabled((_vcpu)->kvm), \
> > + \
> > + .max_level = (_max_level), \
> > + .req_level = PG_LEVEL_4K, \
> > + .goal_level = PG_LEVEL_4K, \
> > + .is_private = \
> > + kvm_mem_is_private((_vcpu)->kvm, (_cr2_or_gpa) >> PAGE_SHIFT), \
> > + \
> > + .pfn = KVM_PFN_ERR_FAULT, \
> > + .hva = KVM_HVA_ERR_BAD, }
> > +
>
> Oof, no. I would much rather refactor kvm_mmu_do_page_fault() as needed than
> have to maintain a macro like this.

Ok, I updated it as follows.

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 0669a8a668ca..e57cc3c56a6d 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -279,8 +279,8 @@ enum {
RET_PF_SPURIOUS,
};

-static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
- u32 err, bool prefetch, int *emulation_type)
+static inline int __kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+ u32 err, bool prefetch, int *emulation_type)
{
struct kvm_page_fault fault = {
.addr = cr2_or_gpa,
@@ -307,6 +307,21 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
}

+ if (IS_ENABLED(CONFIG_RETPOLINE) && fault.is_tdp)
+ r = kvm_tdp_page_fault(vcpu, &fault);
+ else
+ r = vcpu->arch.mmu->page_fault(vcpu, &fault);
+
+ if (fault.write_fault_to_shadow_pgtable && emulation_type)
+ *emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
+ return r;
+}
+
+static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+ u32 err, bool prefetch, int *emulation_type)
+{
+ int r;
+
/*
* Async #PF "faults", a.k.a. prefetch faults, are not faults from the
* guest perspective and have already been counted at the time of the
@@ -315,13 +330,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
if (!prefetch)
vcpu->stat.pf_taken++;

- if (IS_ENABLED(CONFIG_RETPOLINE) && fault.is_tdp)
- r = kvm_tdp_page_fault(vcpu, &fault);
- else
- r = vcpu->arch.mmu->page_fault(vcpu, &fault);
-
- if (fault.write_fault_to_shadow_pgtable && emulation_type)
- *emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
+ r = __kvm_mmu_do_page_fault(vcpu, cr2_or_gpa, err, prefetch, emulation_type);

/*
* Similar to above, prefetch faults aren't truly spurious, and the
--
2.43.2

--
Isaku Yamahata <isaku.yamahata@intel.com>