Add the necessary infrastructure to handle MMU notifiers on KVM/ARM.
As we don't have shadow page tables, the implementation is actually very
simple. The only supported operation is kvm_unmap_hva(), where we remove
the HVA from the 2nd stage translation. All other hooks are NOPs.
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
The aging ops are left unused for the moment, until I actually understand what
they are used for and whether they apply to the ARM architecture.
>From v1:
- Fixed the brown paper bug of invalidating the hva instead of the ipa
arch/arm/include/asm/kvm_asm.h | 2 +
arch/arm/include/asm/kvm_host.h | 19 ++++++++++++++++
arch/arm/kvm/Kconfig | 1 +
arch/arm/kvm/interrupts.S | 18 ++++++++++++++++
arch/arm/kvm/mmu.c | 44 ++++++++++++++++++++++++++++++++++++--
5 files changed, 81 insertions(+), 3 deletions(-)
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 5ee7bd3..18be9bb 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -36,6 +36,7 @@ asm(".equ SMCHYP_HVBAR_W, 0xfffffff0");
#endif /* __ASSEMBLY__ */
#ifndef __ASSEMBLY__
+struct kvm;
struct kvm_vcpu;
extern char __kvm_hyp_init[];
@@ -46,6 +47,7 @@ extern char __kvm_hyp_vector_end[];
extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+extern void __kvm_tlb_flush_vmid(struct kvm *kvm);
extern char __kvm_hyp_code_end[];
#endif
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 555a6f1..1c0c68b 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -109,4 +109,23 @@ struct kvm_vm_stat {
struct kvm_vcpu_stat {
};
+#define KVM_ARCH_WANT_MMU_NOTIFIER
+struct kvm;
+int kvm_unmap_hva(struct kvm *kvm, unsigned long hva);
+
+/* We do not have shadow page tables, hence the empty hooks */
+static inline int kvm_age_hva(struct kvm *kvm, unsigned long hva)
+{
+ return 0;
+}
+
+static inline int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
+{
+ return 0;
+}
+
+static inline void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
+{
+}
+
#endif /* __ARM_KVM_HOST_H__ */
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index ccabbb3..7ce9173 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -36,6 +36,7 @@ config KVM_ARM_HOST
depends on KVM
depends on MMU
depends on CPU_V7 || ARM_VIRT_EXT
+ select MMU_NOTIFIER
---help---
Provides host support for ARM processors.
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index 8b7e5e9..8822fb3 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -351,7 +351,25 @@ return_to_ioctl:
THUMB( orr lr, lr, #1)
mov pc, lr
+ENTRY(__kvm_tlb_flush_vmid)
+ hvc #0 @ Switch to Hyp mode
+ push {r2, r3}
+ ldrd r2, r3, [r0, #KVM_VTTBR]
+ mcrr p15, 6, r2, r3, c2 @ Write VTTBR
+ isb
+ mcr p15, 0, r0, c8, c7, 0 @ TBLIALL
+ dsb
+ isb
+ mov r2, #0
+ mov r3, #0
+ mcrr p15, 6, r2, r3, c2 @ Back to VMID #0
+ isb
+
+ pop {r2, r3}
+ hvc #0 @ Back to SVC
+ mov pc, lr
+ENDPROC(__kvm_tlb_flush_vmid)
.ltorg
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index baeb8a1..3f8d83b 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -245,12 +245,12 @@ void kvm_free_stage2_pgd(struct kvm *kvm)
kvm->arch.pgd = NULL;
}
-static int __user_mem_abort(struct kvm *kvm, phys_addr_t addr, pfn_t pfn)
+static int stage2_set_pte(struct kvm *kvm, phys_addr_t addr, pte_t new_pte)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte, new_pte;
+ pte_t *pte;
/* Create 2nd stage page table mapping - Level 1 */
pgd = kvm->arch.pgd + pgd_index(addr);
@@ -279,12 +279,18 @@ static int __user_mem_abort(struct kvm *kvm, phys_addr_t addr, pfn_t pfn)
pte = pte_offset_kernel(pmd, addr);
/* Create 2nd stage page table mapping - Level 3 */
- new_pte = pfn_pte(pfn, PAGE_KVM_GUEST);
set_pte_ext(pte, new_pte, 0);
return 0;
}
+static int __user_mem_abort(struct kvm *kvm, phys_addr_t addr, pfn_t pfn)
+{
+ pte_t new_pte = pfn_pte(pfn, PAGE_KVM_GUEST);
+
+ return stage2_set_pte(kvm, addr, new_pte);
+}
+
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
gfn_t gfn, struct kvm_memory_slot *memslot)
{
@@ -510,3 +516,35 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
return user_mem_abort(vcpu, fault_ipa, gfn, memslot);
}
+
+int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
+{
+ static const pte_t null_pte;
+ struct kvm_memslots *slots;
+ struct kvm_memory_slot *memslot;
+ int needs_stage2_flush = 0;
+
+ slots = kvm_memslots(kvm);
+
+ /* we only care about the pages that the guest sees */
+ kvm_for_each_memslot(memslot, slots) {
+ unsigned long start = memslot->userspace_addr;
+ unsigned long end;
+
+ end = start + (memslot->npages << PAGE_SHIFT);
+ if (hva >= start && hva < end) {
+ gpa_t gpa_offset = hva - start;
+ gpa_t gpa = (memslot->base_gfn << PAGE_SHIFT) + gpa_offset;
+
+ if (stage2_set_pte(kvm, gpa, null_pte))
+ continue; /* Something bad happened, try to carry on */
+
+ needs_stage2_flush = 1;
+ }
+ }
+
+ if (needs_stage2_flush)
+ __kvm_tlb_flush_vmid(kvm);
+
+ return 0;
+}
--
1.7.3.4
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