diff mbox series

[v7,08/12] KVM: arm64: Define kvm_tlb_flush_vmid_range()

Message ID 20230722022251.3446223-9-rananta@google.com (mailing list archive)
State Superseded
Headers show
Series KVM: arm64: Add support for FEAT_TLBIRANGE | expand

Commit Message

Raghavendra Rao Ananta July 22, 2023, 2:22 a.m. UTC 
Implement the helper kvm_tlb_flush_vmid_range() that acts
as a wrapper for range-based TLB invalidations. For the
given VMID, use the range-based TLBI instructions to do
the job or fallback to invalidating all the TLB entries.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
---
 arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
 arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+)

Comments

Marc Zyngier July 27, 2023, 12:47 p.m. UTC | #1 
On Sat, 22 Jul 2023 03:22:47 +0100,
Raghavendra Rao Ananta <rananta@google.com> wrote:
> 
> Implement the helper kvm_tlb_flush_vmid_range() that acts
> as a wrapper for range-based TLB invalidations. For the
> given VMID, use the range-based TLBI instructions to do
> the job or fallback to invalidating all the TLB entries.
> 
> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> ---
>  arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
>  arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index 8294a9a7e566..5e8b1ff07854 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -754,4 +754,14 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
>   *	   kvm_pgtable_prot format.
>   */
>  enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
> +
> +/**
> + * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
> + *
> + * @mmu:	Stage-2 KVM MMU struct
> + * @addr:	The base Intermediate physical address from which to invalidate
> + * @size:	Size of the range from the base to invalidate
> + */
> +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> +				phys_addr_t addr, size_t size);
>  #endif	/* __ARM64_KVM_PGTABLE_H__ */
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index aa740a974e02..5d14d5d5819a 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -670,6 +670,26 @@ static bool stage2_has_fwb(struct kvm_pgtable *pgt)
>  	return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
>  }
>  
> +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> +				phys_addr_t addr, size_t size)
> +{
> +	unsigned long pages, inval_pages;
> +
> +	if (!system_supports_tlb_range()) {
> +		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
> +		return;
> +	}
> +
> +	pages = size >> PAGE_SHIFT;
> +	while (pages > 0) {
> +		inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
> +		kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
> +
> +		addr += inval_pages << PAGE_SHIFT;
> +		pages -= inval_pages;
> +	}
> +}
> +

This really shouldn't live in pgtable.c. This code gets linked into
the EL2 object. What do you think happens if, for some reason, this
gets called *from EL2*?

Furthermore, this doesn't deal with page tables at all. Why isn't
mmu.c a convenient place for it, as an integral part of
kvm_arch_flush_remote_tlbs_range?

	M.
Marc Zyngier July 27, 2023, 1:01 p.m. UTC | #2 
On Thu, 27 Jul 2023 13:47:06 +0100,
Marc Zyngier <maz@kernel.org> wrote:
> 
> On Sat, 22 Jul 2023 03:22:47 +0100,
> Raghavendra Rao Ananta <rananta@google.com> wrote:
> > 
> > Implement the helper kvm_tlb_flush_vmid_range() that acts
> > as a wrapper for range-based TLB invalidations. For the
> > given VMID, use the range-based TLBI instructions to do
> > the job or fallback to invalidating all the TLB entries.
> > 
> > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> > Reviewed-by: Gavin Shan <gshan@redhat.com>
> > Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> > ---
> >  arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
> >  arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
> >  2 files changed, 30 insertions(+)
> > 
> > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> > index 8294a9a7e566..5e8b1ff07854 100644
> > --- a/arch/arm64/include/asm/kvm_pgtable.h
> > +++ b/arch/arm64/include/asm/kvm_pgtable.h
> > @@ -754,4 +754,14 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
> >   *	   kvm_pgtable_prot format.
> >   */
> >  enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
> > +
> > +/**
> > + * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
> > + *
> > + * @mmu:	Stage-2 KVM MMU struct
> > + * @addr:	The base Intermediate physical address from which to invalidate
> > + * @size:	Size of the range from the base to invalidate
> > + */
> > +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > +				phys_addr_t addr, size_t size);
> >  #endif	/* __ARM64_KVM_PGTABLE_H__ */
> > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> > index aa740a974e02..5d14d5d5819a 100644
> > --- a/arch/arm64/kvm/hyp/pgtable.c
> > +++ b/arch/arm64/kvm/hyp/pgtable.c
> > @@ -670,6 +670,26 @@ static bool stage2_has_fwb(struct kvm_pgtable *pgt)
> >  	return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
> >  }
> >  
> > +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > +				phys_addr_t addr, size_t size)
> > +{
> > +	unsigned long pages, inval_pages;
> > +
> > +	if (!system_supports_tlb_range()) {
> > +		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
> > +		return;
> > +	}
> > +
> > +	pages = size >> PAGE_SHIFT;
> > +	while (pages > 0) {
> > +		inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
> > +		kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
> > +
> > +		addr += inval_pages << PAGE_SHIFT;
> > +		pages -= inval_pages;
> > +	}
> > +}
> > +
> 
> This really shouldn't live in pgtable.c. This code gets linked into
> the EL2 object. What do you think happens if, for some reason, this
> gets called *from EL2*?

Ah, actually, nothing too bad would happen, as we convert the
kvm_call_hyp() into a function call.

But still, we don't need two copies of this stuff, and it can live in
mmu.c.

	M.
Raghavendra Rao Ananta July 31, 2023, 6:01 p.m. UTC | #3 
On Thu, Jul 27, 2023 at 6:01 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On Thu, 27 Jul 2023 13:47:06 +0100,
> Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Sat, 22 Jul 2023 03:22:47 +0100,
> > Raghavendra Rao Ananta <rananta@google.com> wrote:
> > >
> > > Implement the helper kvm_tlb_flush_vmid_range() that acts
> > > as a wrapper for range-based TLB invalidations. For the
> > > given VMID, use the range-based TLBI instructions to do
> > > the job or fallback to invalidating all the TLB entries.
> > >
> > > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> > > Reviewed-by: Gavin Shan <gshan@redhat.com>
> > > Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> > > ---
> > >  arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
> > >  arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
> > >  2 files changed, 30 insertions(+)
> > >
> > > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> > > index 8294a9a7e566..5e8b1ff07854 100644
> > > --- a/arch/arm64/include/asm/kvm_pgtable.h
> > > +++ b/arch/arm64/include/asm/kvm_pgtable.h
> > > @@ -754,4 +754,14 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
> > >   *    kvm_pgtable_prot format.
> > >   */
> > >  enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
> > > +
> > > +/**
> > > + * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
> > > + *
> > > + * @mmu:   Stage-2 KVM MMU struct
> > > + * @addr:  The base Intermediate physical address from which to invalidate
> > > + * @size:  Size of the range from the base to invalidate
> > > + */
> > > +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > > +                           phys_addr_t addr, size_t size);
> > >  #endif     /* __ARM64_KVM_PGTABLE_H__ */
> > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> > > index aa740a974e02..5d14d5d5819a 100644
> > > --- a/arch/arm64/kvm/hyp/pgtable.c
> > > +++ b/arch/arm64/kvm/hyp/pgtable.c
> > > @@ -670,6 +670,26 @@ static bool stage2_has_fwb(struct kvm_pgtable *pgt)
> > >     return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
> > >  }
> > >
> > > +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > > +                           phys_addr_t addr, size_t size)
> > > +{
> > > +   unsigned long pages, inval_pages;
> > > +
> > > +   if (!system_supports_tlb_range()) {
> > > +           kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
> > > +           return;
> > > +   }
> > > +
> > > +   pages = size >> PAGE_SHIFT;
> > > +   while (pages > 0) {
> > > +           inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
> > > +           kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
> > > +
> > > +           addr += inval_pages << PAGE_SHIFT;
> > > +           pages -= inval_pages;
> > > +   }
> > > +}
> > > +
> >
> > This really shouldn't live in pgtable.c. This code gets linked into
> > the EL2 object. What do you think happens if, for some reason, this
> > gets called *from EL2*?
>
> Ah, actually, nothing too bad would happen, as we convert the
> kvm_call_hyp() into a function call.
>
> But still, we don't need two copies of this stuff, and it can live in
> mmu.c.
>
But since we have a couple of references in pgtable.c to
kvm_tlb_flush_vmid_range(), wouldn't that be an (linking) issue if we
moved the definition to mmu.c?

ld: error: undefined symbol: __kvm_nvhe_kvm_tlb_flush_vmid_range
>>> referenced by pgtable.c:1148 (./arch/arm64/kvm/hyp/nvhe/../pgtable.c:1148)
>>>               arch/arm64/kvm/hyp/nvhe/kvm_nvhe.o:(__kvm_nvhe_kvm_pgtable_stage2_unmap) in archive vmlinux.a
...

Or is there some other way to make it work?

- Raghavendra

>         M.
>
> --
> Without deviation from the norm, progress is not possible.
Marc Zyngier Aug. 2, 2023, 11:25 p.m. UTC | #4 
On Mon, 31 Jul 2023 19:01:53 +0100,
Raghavendra Rao Ananta <rananta@google.com> wrote:
> 
> On Thu, Jul 27, 2023 at 6:01 AM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Thu, 27 Jul 2023 13:47:06 +0100,
> > Marc Zyngier <maz@kernel.org> wrote:
> > >
> > > On Sat, 22 Jul 2023 03:22:47 +0100,
> > > Raghavendra Rao Ananta <rananta@google.com> wrote:
> > > >
> > > > Implement the helper kvm_tlb_flush_vmid_range() that acts
> > > > as a wrapper for range-based TLB invalidations. For the
> > > > given VMID, use the range-based TLBI instructions to do
> > > > the job or fallback to invalidating all the TLB entries.
> > > >
> > > > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> > > > Reviewed-by: Gavin Shan <gshan@redhat.com>
> > > > Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> > > > ---
> > > >  arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
> > > >  arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
> > > >  2 files changed, 30 insertions(+)
> > > >
> > > > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> > > > index 8294a9a7e566..5e8b1ff07854 100644
> > > > --- a/arch/arm64/include/asm/kvm_pgtable.h
> > > > +++ b/arch/arm64/include/asm/kvm_pgtable.h
> > > > @@ -754,4 +754,14 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
> > > >   *    kvm_pgtable_prot format.
> > > >   */
> > > >  enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
> > > > +
> > > > +/**
> > > > + * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
> > > > + *
> > > > + * @mmu:   Stage-2 KVM MMU struct
> > > > + * @addr:  The base Intermediate physical address from which to invalidate
> > > > + * @size:  Size of the range from the base to invalidate
> > > > + */
> > > > +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > > > +                           phys_addr_t addr, size_t size);
> > > >  #endif     /* __ARM64_KVM_PGTABLE_H__ */
> > > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> > > > index aa740a974e02..5d14d5d5819a 100644
> > > > --- a/arch/arm64/kvm/hyp/pgtable.c
> > > > +++ b/arch/arm64/kvm/hyp/pgtable.c
> > > > @@ -670,6 +670,26 @@ static bool stage2_has_fwb(struct kvm_pgtable *pgt)
> > > >     return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
> > > >  }
> > > >
> > > > +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > > > +                           phys_addr_t addr, size_t size)
> > > > +{
> > > > +   unsigned long pages, inval_pages;
> > > > +
> > > > +   if (!system_supports_tlb_range()) {
> > > > +           kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
> > > > +           return;
> > > > +   }
> > > > +
> > > > +   pages = size >> PAGE_SHIFT;
> > > > +   while (pages > 0) {
> > > > +           inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
> > > > +           kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
> > > > +
> > > > +           addr += inval_pages << PAGE_SHIFT;
> > > > +           pages -= inval_pages;
> > > > +   }
> > > > +}
> > > > +
> > >
> > > This really shouldn't live in pgtable.c. This code gets linked into
> > > the EL2 object. What do you think happens if, for some reason, this
> > > gets called *from EL2*?
> >
> > Ah, actually, nothing too bad would happen, as we convert the
> > kvm_call_hyp() into a function call.
> >
> > But still, we don't need two copies of this stuff, and it can live in
> > mmu.c.
> >
> But since we have a couple of references in pgtable.c to
> kvm_tlb_flush_vmid_range(), wouldn't that be an (linking) issue if we
> moved the definition to mmu.c?
> 
> ld: error: undefined symbol: __kvm_nvhe_kvm_tlb_flush_vmid_range
> >>> referenced by pgtable.c:1148 (./arch/arm64/kvm/hyp/nvhe/../pgtable.c:1148)
> >>>               arch/arm64/kvm/hyp/nvhe/kvm_nvhe.o:(__kvm_nvhe_kvm_pgtable_stage2_unmap) in archive vmlinux.a
> ...

Ah crap, I missed that. What a mess. Forget it then. It really is a
shame that all the neat separation between mmu.c and pgtable.c that we
were aiming for is ultimately lost.

	M.
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 8294a9a7e566..5e8b1ff07854 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -754,4 +754,14 @@  enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
  *	   kvm_pgtable_prot format.
  */
 enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
+
+/**
+ * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
+ *
+ * @mmu:	Stage-2 KVM MMU struct
+ * @addr:	The base Intermediate physical address from which to invalidate
+ * @size:	Size of the range from the base to invalidate
+ */
+void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
+				phys_addr_t addr, size_t size);
 #endif	/* __ARM64_KVM_PGTABLE_H__ */
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index aa740a974e02..5d14d5d5819a 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -670,6 +670,26 @@  static bool stage2_has_fwb(struct kvm_pgtable *pgt)
 	return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
 }
 
+void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
+				phys_addr_t addr, size_t size)
+{
+	unsigned long pages, inval_pages;
+
+	if (!system_supports_tlb_range()) {
+		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
+		return;
+	}
+
+	pages = size >> PAGE_SHIFT;
+	while (pages > 0) {
+		inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
+		kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
+
+		addr += inval_pages << PAGE_SHIFT;
+		pages -= inval_pages;
+	}
+}
+
 #define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt))
 
 static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot,