On Sun, Aug 19, 2012 at 9:00 AM, Avi Kivity <avi@xxxxxxxxxx> wrote:
> On 08/19/2012 12:38 PM, Peter Maydell wrote:
>> On 19 August 2012 05:34, Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>> On Thu, Aug 16, 2012 at 2:25 PM, Alexander Graf <agraf@xxxxxxx> wrote:
>>>> A single hva can have multiple gpas mapped, no? At least that's what I gathered
>>>> from the discussion about my attempt to a function similar to this :).
>>
>>> I don't think this is the case for ARM, can you provide an example? We
>>> use gfn_to_pfn_prot and only allow user memory regions. What you
>>> suggest would be multiple physical addresses pointing to the same
>>> memory bank, I don't think that makes any sense on ARM hardware, for
>>> x86 and PPC I don't know.
>>
>> I don't know what an hva is,
>
> host virtual address
>
> (see Documentation/virtual/kvm/mmu.txt for more TLAs in this area).
>
> but yes, ARM boards can have the same
>> block of RAM aliased into multiple places in the physical address space.
>> (we don't currently bother to implement the aliases in qemu's vexpress-a15
>> though because it's a bunch of mappings of the low 2GB into high
>> addresses mostly intended to let you test LPAE code without having to
>> put lots of RAM on the hardware).
I stand corrected.
>
> Even if it weren't common, the API allows it, so we must behave sensibly.
>
true, this should be a solution:
commit 2a8661fd7e6c15889a20a4547bd7861e84b778a8
Author: Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
Date: Sun Aug 19 15:52:10 2012 -0400
KVM: ARM: A single hva can map multiple gpas
Handle mmu notifier ops for every such mapping.
Signed-off-by: Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 3df4fa8..9b23230 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -754,11 +754,14 @@ int kvm_handle_guest_abort(struct kvm_vcpu
*vcpu, struct kvm_run *run)
return ret ? ret : 1;
}
-static bool hva_to_gpa(struct kvm *kvm, unsigned long hva, gpa_t *gpa)
+static int handle_hva_to_gpa(struct kvm *kvm, unsigned long hva,
+ void (*handler)(struct kvm *kvm, unsigned long hva,
+ gpa_t gpa, void *data),
+ void *data)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
- bool found = false;
+ int cnt = 0;
slots = kvm_memslots(kvm);
@@ -769,31 +772,36 @@ static bool hva_to_gpa(struct kvm *kvm, unsigned
long hva, gpa_t *gpa)
end = start + (memslot->npages << PAGE_SHIFT);
if (hva >= start && hva < end) {
+ gpa_t gpa;
gpa_t gpa_offset = hva - start;
- *gpa = (memslot->base_gfn << PAGE_SHIFT) + gpa_offset;
- found = true;
- /* no overlapping memslots allowed: break */
- break;
+ gpa = (memslot->base_gfn << PAGE_SHIFT) + gpa_offset;
+ handler(kvm, hva, gpa, data);
+ cnt++;
}
}
- return found;
+ return cnt;
+}
+
+static void kvm_unmap_hva_handler(struct kvm *kvm, unsigned long hva,
+ gpa_t gpa, void *data)
+{
+ spin_lock(&kvm->arch.pgd_lock);
+ stage2_clear_pte(kvm, gpa);
+ spin_unlock(&kvm->arch.pgd_lock);
}
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
- bool found;
- gpa_t gpa;
+ int found;
if (!kvm->arch.pgd)
return 0;
- found = hva_to_gpa(kvm, hva, &gpa);
- if (found) {
- spin_lock(&kvm->arch.pgd_lock);
- stage2_clear_pte(kvm, gpa);
- spin_unlock(&kvm->arch.pgd_lock);
- }
+ found = handle_hva_to_gpa(kvm, hva, &kvm_unmap_hva_handler, NULL);
+ if (found > 0)
+ __kvm_tlb_flush_vmid(kvm);
+
return 0;
}
@@ -814,21 +822,27 @@ int kvm_unmap_hva_range(struct kvm *kvm,
return 0;
}
+static void kvm_set_spte_handler(struct kvm *kvm, unsigned long hva,
+ gpa_t gpa, void *data)
+{
+ pte_t *pte = (pte_t *)data;
+
+ spin_lock(&kvm->arch.pgd_lock);
+ stage2_set_pte(kvm, NULL, gpa, pte);
+ spin_unlock(&kvm->arch.pgd_lock);
+}
+
+
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
- gpa_t gpa;
- bool found;
+ int found;
if (!kvm->arch.pgd)
return;
- found = hva_to_gpa(kvm, hva, &gpa);
- if (found) {
- spin_lock(&kvm->arch.pgd_lock);
- stage2_set_pte(kvm, NULL, gpa, &pte);
- spin_unlock(&kvm->arch.pgd_lock);
+ found = handle_hva_to_gpa(kvm, hva, &kvm_set_spte_handler, &pte);
+ if (found > 0)
__kvm_tlb_flush_vmid(kvm);
- }
}
void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
--
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