1. Patchew
  2. linux
  3. [RFC 00/14] KVM: x86/MMU: Formalize the Shadow MMU
  4. View patch

[RFC 04/14] KVM: x86/MMU: Expose functions for paging_tmpl.h

Ben Gardon posted 14 patches 2 years, 8 months ago
There is a newer version of this series
[RFC 04/14] KVM: x86/MMU: Expose functions for paging_tmpl.h
Posted by Ben Gardon 2 years, 8 months ago 
In preparation for moving paging_tmpl.h to shadow_mmu.c, expose various
functions it needs through mmu_internal.h. This includes modifying the
BUILD_MMU_ROLE_ACCESSOR macro so that it does not automatically include
the static label, since some but not all of the accessors are needed by
paging_tmpl.h.

No functional change intended.

Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/x86/kvm/mmu/mmu.c          | 32 ++++++++++++++++----------------
 arch/x86/kvm/mmu/mmu_internal.h | 16 ++++++++++++++++
 2 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index bf14e181eb12..a17e8a79e4df 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -153,18 +153,18 @@ BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
  * and the vCPU may be incorrect/irrelevant.
  */
 #define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name)		\
-static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)	\
+inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)	\
 {								\
 	return !!(mmu->cpu_role. base_or_ext . reg##_##name);	\
 }
 BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
-BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
+static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
 BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smep);
-BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
-BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
-BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
+static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
+static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
+static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
 BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
-BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);
+static BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);
 
 static inline bool is_cr0_pg(struct kvm_mmu *mmu)
 {
@@ -210,7 +210,7 @@ void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
 	kvm_flush_remote_tlbs_with_range(kvm, &range);
 }
 
-static gfn_t get_mmio_spte_gfn(u64 spte)
+gfn_t get_mmio_spte_gfn(u64 spte)
 {
 	u64 gpa = spte & shadow_nonpresent_or_rsvd_lower_gfn_mask;
 
@@ -240,7 +240,7 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
 	return likely(kvm_gen == spte_gen);
 }
 
-static int is_cpuid_PSE36(void)
+int is_cpuid_PSE36(void)
 {
 	return 1;
 }
@@ -279,7 +279,7 @@ void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
 	}
 }
 
-static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
+int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
 {
 	int r;
 
@@ -818,8 +818,8 @@ static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
 	return -EFAULT;
 }
 
-static int handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
-			       unsigned int access)
+int handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+			unsigned int access)
 {
 	/* The pfn is invalid, report the error! */
 	if (unlikely(is_error_pfn(fault->pfn)))
@@ -1275,8 +1275,8 @@ static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
 	return RET_PF_RETRY;
 }
 
-static bool page_fault_handle_page_track(struct kvm_vcpu *vcpu,
-					 struct kvm_page_fault *fault)
+bool page_fault_handle_page_track(struct kvm_vcpu *vcpu,
+				  struct kvm_page_fault *fault)
 {
 	if (unlikely(fault->rsvd))
 		return false;
@@ -1338,7 +1338,7 @@ 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)
+int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 {
 	struct kvm_memory_slot *slot = fault->slot;
 	bool async;
@@ -1403,8 +1403,8 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *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)
+bool is_page_fault_stale(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+			 int mmu_seq)
 {
 	struct kvm_mmu_page *sp = to_shadow_page(vcpu->arch.mmu->root.hpa);
 
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 74a99b67f09e..957376fcb333 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -341,6 +341,22 @@ bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp);
 void walk_shadow_page_lockless_begin(struct kvm_vcpu *vcpu);
 void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu);
 
+int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect);
 bool need_topup_split_caches_or_resched(struct kvm *kvm);
 int topup_split_caches(struct kvm *kvm);
+
+bool is_page_fault_stale(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+			 int mmu_seq);
+bool page_fault_handle_page_track(struct kvm_vcpu *vcpu,
+				  struct kvm_page_fault *fault);
+int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault);
+int handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
+			unsigned int access);
+
+gfn_t get_mmio_spte_gfn(u64 spte);
+
+bool is_efer_nx(struct kvm_mmu *mmu);
+bool is_cr4_smep(struct kvm_mmu *mmu);
+bool is_cr0_wp(struct kvm_mmu *mmu);
+int is_cpuid_PSE36(void);
 #endif /* __KVM_X86_MMU_INTERNAL_H */
-- 
2.39.0.314.g84b9a713c41-goog
Re: [RFC 04/14] KVM: x86/MMU: Expose functions for paging_tmpl.h
Posted by David Matlack 2 years, 8 months ago 
On Wed, Dec 21, 2022 at 10:24:08PM +0000, Ben Gardon wrote:
> In preparation for moving paging_tmpl.h to shadow_mmu.c, expose various
> functions it needs through mmu_internal.h. This includes modifying the
> BUILD_MMU_ROLE_ACCESSOR macro so that it does not automatically include
> the static label, since some but not all of the accessors are needed by
> paging_tmpl.h.
> 
> No functional change intended.
> 
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
>  arch/x86/kvm/mmu/mmu.c          | 32 ++++++++++++++++----------------
>  arch/x86/kvm/mmu/mmu_internal.h | 16 ++++++++++++++++
>  2 files changed, 32 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index bf14e181eb12..a17e8a79e4df 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -153,18 +153,18 @@ BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
>   * and the vCPU may be incorrect/irrelevant.
>   */
>  #define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name)		\
> -static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)	\
> +inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)	\
>  {								\
>  	return !!(mmu->cpu_role. base_or_ext . reg##_##name);	\
>  }
>  BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
> -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
> +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
>  BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smep);
> -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
> -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
> -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
> +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
> +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
> +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
>  BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
> -BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);
> +static BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);

Suggest moving all the BUILD_MMU_ROLE*() macros to mmu_internal.h, since
they are already static inline. That would be a cleaner patch and reduce
future churn if shadow_mmu.c ever needs to use a different role accessor
at some point.

>  
>  static inline bool is_cr0_pg(struct kvm_mmu *mmu)
>  {
> @@ -210,7 +210,7 @@ void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
>  	kvm_flush_remote_tlbs_with_range(kvm, &range);
>  }
>  
> -static gfn_t get_mmio_spte_gfn(u64 spte)
> +gfn_t get_mmio_spte_gfn(u64 spte)
>  {
>  	u64 gpa = spte & shadow_nonpresent_or_rsvd_lower_gfn_mask;
>  
> @@ -240,7 +240,7 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
>  	return likely(kvm_gen == spte_gen);
>  }
>  
> -static int is_cpuid_PSE36(void)
> +int is_cpuid_PSE36(void)
>  {
>  	return 1;
>  }

Can we just drop is_cpuid_PSE36(), e.g. as a precursor patch? It just
returns 1...
Re: [RFC 04/14] KVM: x86/MMU: Expose functions for paging_tmpl.h
Posted by Ben Gardon 2 years, 8 months ago 
On Fri, Jan 6, 2023 at 11:49 AM David Matlack <dmatlack@google.com> wrote:
>
> On Wed, Dec 21, 2022 at 10:24:08PM +0000, Ben Gardon wrote:
> > In preparation for moving paging_tmpl.h to shadow_mmu.c, expose various
> > functions it needs through mmu_internal.h. This includes modifying the
> > BUILD_MMU_ROLE_ACCESSOR macro so that it does not automatically include
> > the static label, since some but not all of the accessors are needed by
> > paging_tmpl.h.
> >
> > No functional change intended.
> >
> > Signed-off-by: Ben Gardon <bgardon@google.com>
> > ---
> >  arch/x86/kvm/mmu/mmu.c          | 32 ++++++++++++++++----------------
> >  arch/x86/kvm/mmu/mmu_internal.h | 16 ++++++++++++++++
> >  2 files changed, 32 insertions(+), 16 deletions(-)
> >
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index bf14e181eb12..a17e8a79e4df 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -153,18 +153,18 @@ BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
> >   * and the vCPU may be incorrect/irrelevant.
> >   */
> >  #define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name)              \
> > -static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)     \
> > +inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)    \
> >  {                                                            \
> >       return !!(mmu->cpu_role. base_or_ext . reg##_##name);   \
> >  }
> >  BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
> > -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
> > +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pse);
> >  BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smep);
> > -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
> > -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
> > -BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
> > +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, smap);
> > +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, pke);
> > +static BUILD_MMU_ROLE_ACCESSOR(ext,  cr4, la57);
> >  BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
> > -BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);
> > +static BUILD_MMU_ROLE_ACCESSOR(ext,  efer, lma);
>
> Suggest moving all the BUILD_MMU_ROLE*() macros to mmu_internal.h, since
> they are already static inline. That would be a cleaner patch and reduce
> future churn if shadow_mmu.c ever needs to use a different role accessor
> at some point.

That sounds reasonable. Will do in V1.

>
> >
> >  static inline bool is_cr0_pg(struct kvm_mmu *mmu)
> >  {
> > @@ -210,7 +210,7 @@ void kvm_flush_remote_tlbs_with_address(struct kvm *kvm,
> >       kvm_flush_remote_tlbs_with_range(kvm, &range);
> >  }
> >
> > -static gfn_t get_mmio_spte_gfn(u64 spte)
> > +gfn_t get_mmio_spte_gfn(u64 spte)
> >  {
> >       u64 gpa = spte & shadow_nonpresent_or_rsvd_lower_gfn_mask;
> >
> > @@ -240,7 +240,7 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
> >       return likely(kvm_gen == spte_gen);
> >  }
> >
> > -static int is_cpuid_PSE36(void)
> > +int is_cpuid_PSE36(void)
> >  {
> >       return 1;
> >  }
>
> Can we just drop is_cpuid_PSE36(), e.g. as a precursor patch? It just
> returns 1...

Yeah, good idea. Looks like we can eliminate a little dead code doing that too.

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.