Re: [PATCH v3 8/9] KVM: arm64: selftests: Add infrastructure for using stage-2 in guest

2026-07-23 Thread Wei-Lin Chang 
On Thu, Jul 23, 2026 at 11:47:16AM +0900, Itaru Kitayama wrote:
> On Sat, May 16, 2026 at 07:30:02PM +0100, Wei-Lin Chang wrote:
> > Add a stage-2 page table generator, the s2_mmu structure, and vEL2
> > stage-2 preparation code for a guest hypervisor to turn on stage-2
> > translation for its nested guest.
> > 
> > Signed-off-by: Wei-Lin Chang 
> > ---
> >  .../selftests/kvm/arm64/hello_nested.c|   2 +-
> >  .../selftests/kvm/arm64/shadow_stage2.c   |   2 +-
> >  .../selftests/kvm/include/arm64/nested.h  |  15 +-
> >  .../testing/selftests/kvm/lib/arm64/nested.c  | 145 +-
> >  4 files changed, 160 insertions(+), 4 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/kvm/arm64/hello_nested.c 
> > b/tools/testing/selftests/kvm/arm64/hello_nested.c
> > index 9ed5285f5f2d..b57e41c73214 100644
> > --- a/tools/testing/selftests/kvm/arm64/hello_nested.c
> > +++ b/tools/testing/selftests/kvm/arm64/hello_nested.c
> > @@ -62,7 +62,7 @@ static void guest_code(void)
> > l2_stack_top = ucall_translate_to_gpa(&l2_stack[L2STACKSZ]);
> >  
> > init_vcpu(&vcpu, l2_pc, l2_stack_top);
> > -   prepare_hyp();
> > +   prepare_hyp_no_s2();
> >  
> > ret = run_l2(&vcpu, &hyp_data);
> > GUEST_ASSERT_EQ(ret, ARM_EXCEPTION_TRAP);
> > diff --git a/tools/testing/selftests/kvm/arm64/shadow_stage2.c 
> > b/tools/testing/selftests/kvm/arm64/shadow_stage2.c
> > index c5332b8b5683..2b274b810dcf 100644
> > --- a/tools/testing/selftests/kvm/arm64/shadow_stage2.c
> > +++ b/tools/testing/selftests/kvm/arm64/shadow_stage2.c
> > @@ -72,7 +72,7 @@ static void guest_code(void)
> > l2_pc = ucall_translate_to_gpa(l2_guest_code);
> >  
> > init_vcpu(&vcpu, l2_pc, l2_stack_top);
> > -   prepare_hyp();
> > +   prepare_hyp_no_s2();
> >  
> > while (true) {
> > GUEST_PRINTF("L2 enter\n");
> > diff --git a/tools/testing/selftests/kvm/include/arm64/nested.h 
> > b/tools/testing/selftests/kvm/include/arm64/nested.h
> > index fc59fabff12d..1bcbb31b8d67 100644
> > --- a/tools/testing/selftests/kvm/include/arm64/nested.h
> > +++ b/tools/testing/selftests/kvm/include/arm64/nested.h
> > @@ -38,6 +38,14 @@ struct vcpu {
> > struct cpu_context context;
> >  };
> >  
> > +struct s2_mmu {
> > +   gpa_t pgd;
> > +   unsigned int vmid;
> > +   unsigned int page_size_shift;
> > +   u64 vtcr;
> > +   u64 ipa_bits;
> > +};
> > +
> >  /*
> >   * KVM has host_data and hyp_context, combine them because we're only doing
> >   * hyp context.
> > @@ -56,8 +64,13 @@ struct page_pool {
> >  size_t get_page_size(void);
> >  gpa_t alloc_page(struct page_pool *pp);
> >  bool has_tgran_2(u64 mmfr0, size_t size);
> > -void prepare_hyp(void);
> > +void prepare_hyp_no_s2(void);
> > +void prepare_hyp(struct s2_mmu *mmu);
> >  void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t l2_stack_top);
> > +void create_s2_mapping(struct s2_mmu *mmu, u64 ipa, u64 pa, size_t size,
> > +  struct page_pool *pp);
> > +void init_s2_mmu(struct s2_mmu *mmu, unsigned int vmid, gpa_t pgd,
> > +size_t page_size, u64 ipa_bits);
> >  int run_l2(struct vcpu *vcpu, struct hyp_data *hyp_data);
> >  
> >  u64 do_hvc(u64 action, u64 arg1, u64 arg2);
> > diff --git a/tools/testing/selftests/kvm/lib/arm64/nested.c 
> > b/tools/testing/selftests/kvm/lib/arm64/nested.c
> > index cda41f355263..9848d607ef64 100644
> > --- a/tools/testing/selftests/kvm/lib/arm64/nested.c
> > +++ b/tools/testing/selftests/kvm/lib/arm64/nested.c
> > @@ -71,13 +71,22 @@ gpa_t alloc_page(struct page_pool *pp)
> > }
> >  }
> >  
> > -void prepare_hyp(void)
> > +void prepare_hyp_no_s2(void)
> >  {
> > write_sysreg(HCR_EL2_E2H | HCR_EL2_RW, hcr_el2);
> > write_sysreg(hyp_vectors, vbar_el2);
> > isb();
> >  }
> >  
> > +void prepare_hyp(struct s2_mmu *mmu)
> > +{
> > +   write_sysreg(mmu->vtcr, vtcr_el2);
> > +   write_sysreg(mmu->pgd | ((u64)mmu->vmid << 48), vttbr_el2);
> > +   write_sysreg(HCR_EL2_E2H | HCR_EL2_RW | HCR_EL2_VM, hcr_el2);
> > +   write_sysreg(hyp_vectors, vbar_el2);
> > +   isb();
> > +}
> > +
> >  void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t l2_stack_top)
> >  {
> > memset(vcpu, 0, sizeof(*vcpu));
> > @@ -86,6 +95,140 @@ void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t 
> > l2_stack_top)
> > vcpu->context.sys_regs[SP_EL1] = l2_stack_top;
> >  }
> >  
> > +static int stage2_levels(unsigned int page_size_shift, u64 ipa_bits)
> > +{
> > +   /* taken from ARM64_HW_PGTABLE_LEVELS(ipa) in KVM */
> > +   return (ipa_bits - 4) / (page_size_shift - 3);
> > +}
> > +
> > +static u64 get_index(struct s2_mmu *mmu, u64 ipa, int level)
> > +{
> > +   int width = mmu->page_size_shift - 3;
> > +   int shift_amount = mmu->page_size_shift + (3 - level) * width;
> > +
> > +   return (ipa >> shift_amount) & GENMASK_ULL(width - 1, 0);
> > +}
> > +
> > +static u64 pte_gpa_to_gva(u64 gpa)
> > +{
> > +   /*
> > +* This depends on how the memory used for s2pt is mapped in GVA,
> > +* currently it is

Re: [PATCH v3 8/9] KVM: arm64: selftests: Add infrastructure for using stage-2 in guest

2026-07-22 Thread Itaru Kitayama 
On Sat, May 16, 2026 at 07:30:02PM +0100, Wei-Lin Chang wrote:
> Add a stage-2 page table generator, the s2_mmu structure, and vEL2
> stage-2 preparation code for a guest hypervisor to turn on stage-2
> translation for its nested guest.
> 
> Signed-off-by: Wei-Lin Chang 
> ---
>  .../selftests/kvm/arm64/hello_nested.c|   2 +-
>  .../selftests/kvm/arm64/shadow_stage2.c   |   2 +-
>  .../selftests/kvm/include/arm64/nested.h  |  15 +-
>  .../testing/selftests/kvm/lib/arm64/nested.c  | 145 +-
>  4 files changed, 160 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/arm64/hello_nested.c 
> b/tools/testing/selftests/kvm/arm64/hello_nested.c
> index 9ed5285f5f2d..b57e41c73214 100644
> --- a/tools/testing/selftests/kvm/arm64/hello_nested.c
> +++ b/tools/testing/selftests/kvm/arm64/hello_nested.c
> @@ -62,7 +62,7 @@ static void guest_code(void)
>   l2_stack_top = ucall_translate_to_gpa(&l2_stack[L2STACKSZ]);
>  
>   init_vcpu(&vcpu, l2_pc, l2_stack_top);
> - prepare_hyp();
> + prepare_hyp_no_s2();
>  
>   ret = run_l2(&vcpu, &hyp_data);
>   GUEST_ASSERT_EQ(ret, ARM_EXCEPTION_TRAP);
> diff --git a/tools/testing/selftests/kvm/arm64/shadow_stage2.c 
> b/tools/testing/selftests/kvm/arm64/shadow_stage2.c
> index c5332b8b5683..2b274b810dcf 100644
> --- a/tools/testing/selftests/kvm/arm64/shadow_stage2.c
> +++ b/tools/testing/selftests/kvm/arm64/shadow_stage2.c
> @@ -72,7 +72,7 @@ static void guest_code(void)
>   l2_pc = ucall_translate_to_gpa(l2_guest_code);
>  
>   init_vcpu(&vcpu, l2_pc, l2_stack_top);
> - prepare_hyp();
> + prepare_hyp_no_s2();
>  
>   while (true) {
>   GUEST_PRINTF("L2 enter\n");
> diff --git a/tools/testing/selftests/kvm/include/arm64/nested.h 
> b/tools/testing/selftests/kvm/include/arm64/nested.h
> index fc59fabff12d..1bcbb31b8d67 100644
> --- a/tools/testing/selftests/kvm/include/arm64/nested.h
> +++ b/tools/testing/selftests/kvm/include/arm64/nested.h
> @@ -38,6 +38,14 @@ struct vcpu {
>   struct cpu_context context;
>  };
>  
> +struct s2_mmu {
> + gpa_t pgd;
> + unsigned int vmid;
> + unsigned int page_size_shift;
> + u64 vtcr;
> + u64 ipa_bits;
> +};
> +
>  /*
>   * KVM has host_data and hyp_context, combine them because we're only doing
>   * hyp context.
> @@ -56,8 +64,13 @@ struct page_pool {
>  size_t get_page_size(void);
>  gpa_t alloc_page(struct page_pool *pp);
>  bool has_tgran_2(u64 mmfr0, size_t size);
> -void prepare_hyp(void);
> +void prepare_hyp_no_s2(void);
> +void prepare_hyp(struct s2_mmu *mmu);
>  void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t l2_stack_top);
> +void create_s2_mapping(struct s2_mmu *mmu, u64 ipa, u64 pa, size_t size,
> +struct page_pool *pp);
> +void init_s2_mmu(struct s2_mmu *mmu, unsigned int vmid, gpa_t pgd,
> +  size_t page_size, u64 ipa_bits);
>  int run_l2(struct vcpu *vcpu, struct hyp_data *hyp_data);
>  
>  u64 do_hvc(u64 action, u64 arg1, u64 arg2);
> diff --git a/tools/testing/selftests/kvm/lib/arm64/nested.c 
> b/tools/testing/selftests/kvm/lib/arm64/nested.c
> index cda41f355263..9848d607ef64 100644
> --- a/tools/testing/selftests/kvm/lib/arm64/nested.c
> +++ b/tools/testing/selftests/kvm/lib/arm64/nested.c
> @@ -71,13 +71,22 @@ gpa_t alloc_page(struct page_pool *pp)
>   }
>  }
>  
> -void prepare_hyp(void)
> +void prepare_hyp_no_s2(void)
>  {
>   write_sysreg(HCR_EL2_E2H | HCR_EL2_RW, hcr_el2);
>   write_sysreg(hyp_vectors, vbar_el2);
>   isb();
>  }
>  
> +void prepare_hyp(struct s2_mmu *mmu)
> +{
> + write_sysreg(mmu->vtcr, vtcr_el2);
> + write_sysreg(mmu->pgd | ((u64)mmu->vmid << 48), vttbr_el2);
> + write_sysreg(HCR_EL2_E2H | HCR_EL2_RW | HCR_EL2_VM, hcr_el2);
> + write_sysreg(hyp_vectors, vbar_el2);
> + isb();
> +}
> +
>  void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t l2_stack_top)
>  {
>   memset(vcpu, 0, sizeof(*vcpu));
> @@ -86,6 +95,140 @@ void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t 
> l2_stack_top)
>   vcpu->context.sys_regs[SP_EL1] = l2_stack_top;
>  }
>  
> +static int stage2_levels(unsigned int page_size_shift, u64 ipa_bits)
> +{
> + /* taken from ARM64_HW_PGTABLE_LEVELS(ipa) in KVM */
> + return (ipa_bits - 4) / (page_size_shift - 3);
> +}
> +
> +static u64 get_index(struct s2_mmu *mmu, u64 ipa, int level)
> +{
> + int width = mmu->page_size_shift - 3;
> + int shift_amount = mmu->page_size_shift + (3 - level) * width;
> +
> + return (ipa >> shift_amount) & GENMASK_ULL(width - 1, 0);
> +}
> +
> +static u64 pte_gpa_to_gva(u64 gpa)
> +{
> + /*
> +  * This depends on how the memory used for s2pt is mapped in GVA,
> +  * currently it is assumed they are idmapped.
> +  */
> + return gpa;
> +}
> +
> +static u64 pte_to_pt_base(u64 pte)
> +{
> + return pte & GENMASK_ULL(47, 12);
> +}
> +
> +#define S2_PTE_AF(1ULL << 10)
> +#define S2_PTE_SH_INNER

[PATCH v3 8/9] KVM: arm64: selftests: Add infrastructure for using stage-2 in guest

2026-05-16 Thread Wei-Lin Chang 
Add a stage-2 page table generator, the s2_mmu structure, and vEL2
stage-2 preparation code for a guest hypervisor to turn on stage-2
translation for its nested guest.

Signed-off-by: Wei-Lin Chang 
---
 .../selftests/kvm/arm64/hello_nested.c|   2 +-
 .../selftests/kvm/arm64/shadow_stage2.c   |   2 +-
 .../selftests/kvm/include/arm64/nested.h  |  15 +-
 .../testing/selftests/kvm/lib/arm64/nested.c  | 145 +-
 4 files changed, 160 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/kvm/arm64/hello_nested.c 
b/tools/testing/selftests/kvm/arm64/hello_nested.c
index 9ed5285f5f2d..b57e41c73214 100644
--- a/tools/testing/selftests/kvm/arm64/hello_nested.c
+++ b/tools/testing/selftests/kvm/arm64/hello_nested.c
@@ -62,7 +62,7 @@ static void guest_code(void)
l2_stack_top = ucall_translate_to_gpa(&l2_stack[L2STACKSZ]);
 
init_vcpu(&vcpu, l2_pc, l2_stack_top);
-   prepare_hyp();
+   prepare_hyp_no_s2();
 
ret = run_l2(&vcpu, &hyp_data);
GUEST_ASSERT_EQ(ret, ARM_EXCEPTION_TRAP);
diff --git a/tools/testing/selftests/kvm/arm64/shadow_stage2.c 
b/tools/testing/selftests/kvm/arm64/shadow_stage2.c
index c5332b8b5683..2b274b810dcf 100644
--- a/tools/testing/selftests/kvm/arm64/shadow_stage2.c
+++ b/tools/testing/selftests/kvm/arm64/shadow_stage2.c
@@ -72,7 +72,7 @@ static void guest_code(void)
l2_pc = ucall_translate_to_gpa(l2_guest_code);
 
init_vcpu(&vcpu, l2_pc, l2_stack_top);
-   prepare_hyp();
+   prepare_hyp_no_s2();
 
while (true) {
GUEST_PRINTF("L2 enter\n");
diff --git a/tools/testing/selftests/kvm/include/arm64/nested.h 
b/tools/testing/selftests/kvm/include/arm64/nested.h
index fc59fabff12d..1bcbb31b8d67 100644
--- a/tools/testing/selftests/kvm/include/arm64/nested.h
+++ b/tools/testing/selftests/kvm/include/arm64/nested.h
@@ -38,6 +38,14 @@ struct vcpu {
struct cpu_context context;
 };
 
+struct s2_mmu {
+   gpa_t pgd;
+   unsigned int vmid;
+   unsigned int page_size_shift;
+   u64 vtcr;
+   u64 ipa_bits;
+};
+
 /*
  * KVM has host_data and hyp_context, combine them because we're only doing
  * hyp context.
@@ -56,8 +64,13 @@ struct page_pool {
 size_t get_page_size(void);
 gpa_t alloc_page(struct page_pool *pp);
 bool has_tgran_2(u64 mmfr0, size_t size);
-void prepare_hyp(void);
+void prepare_hyp_no_s2(void);
+void prepare_hyp(struct s2_mmu *mmu);
 void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t l2_stack_top);
+void create_s2_mapping(struct s2_mmu *mmu, u64 ipa, u64 pa, size_t size,
+  struct page_pool *pp);
+void init_s2_mmu(struct s2_mmu *mmu, unsigned int vmid, gpa_t pgd,
+size_t page_size, u64 ipa_bits);
 int run_l2(struct vcpu *vcpu, struct hyp_data *hyp_data);
 
 u64 do_hvc(u64 action, u64 arg1, u64 arg2);
diff --git a/tools/testing/selftests/kvm/lib/arm64/nested.c 
b/tools/testing/selftests/kvm/lib/arm64/nested.c
index cda41f355263..9848d607ef64 100644
--- a/tools/testing/selftests/kvm/lib/arm64/nested.c
+++ b/tools/testing/selftests/kvm/lib/arm64/nested.c
@@ -71,13 +71,22 @@ gpa_t alloc_page(struct page_pool *pp)
}
 }
 
-void prepare_hyp(void)
+void prepare_hyp_no_s2(void)
 {
write_sysreg(HCR_EL2_E2H | HCR_EL2_RW, hcr_el2);
write_sysreg(hyp_vectors, vbar_el2);
isb();
 }
 
+void prepare_hyp(struct s2_mmu *mmu)
+{
+   write_sysreg(mmu->vtcr, vtcr_el2);
+   write_sysreg(mmu->pgd | ((u64)mmu->vmid << 48), vttbr_el2);
+   write_sysreg(HCR_EL2_E2H | HCR_EL2_RW | HCR_EL2_VM, hcr_el2);
+   write_sysreg(hyp_vectors, vbar_el2);
+   isb();
+}
+
 void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t l2_stack_top)
 {
memset(vcpu, 0, sizeof(*vcpu));
@@ -86,6 +95,140 @@ void init_vcpu(struct vcpu *vcpu, gpa_t l2_pc, gpa_t 
l2_stack_top)
vcpu->context.sys_regs[SP_EL1] = l2_stack_top;
 }
 
+static int stage2_levels(unsigned int page_size_shift, u64 ipa_bits)
+{
+   /* taken from ARM64_HW_PGTABLE_LEVELS(ipa) in KVM */
+   return (ipa_bits - 4) / (page_size_shift - 3);
+}
+
+static u64 get_index(struct s2_mmu *mmu, u64 ipa, int level)
+{
+   int width = mmu->page_size_shift - 3;
+   int shift_amount = mmu->page_size_shift + (3 - level) * width;
+
+   return (ipa >> shift_amount) & GENMASK_ULL(width - 1, 0);
+}
+
+static u64 pte_gpa_to_gva(u64 gpa)
+{
+   /*
+* This depends on how the memory used for s2pt is mapped in GVA,
+* currently it is assumed they are idmapped.
+*/
+   return gpa;
+}
+
+static u64 pte_to_pt_base(u64 pte)
+{
+   return pte & GENMASK_ULL(47, 12);
+}
+
+#define S2_PTE_AF  (1ULL << 10)
+#define S2_PTE_SH_INNER(3ULL << 8)
+#define S2_PTE_S2AP_RW (3ULL << 6)
+#define S2_PTE_ATTR_NORMAL_WB  (0xfULL << 2)
+#define S2_PTE_TYPE_TABLE  (1ULL << 1)
+#define S2_PTE_TYPE_PAGE   (1ULL << 1)
+#define S2_PTE_VALID   1ULL
+
+/* No block mapping