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KVM: PPC: e500: Support large page mappings of PFNMAP vmas.

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This allows large pages to be used on guest mappings backed by things like
/dev/mem, resulting in a significant speedup when guest memory
is mapped this way (it's useful for directly-assigned MMIO, too).

This is not a substitute for hugetlbfs integration, but is useful for
configurations where devices are directly assigned on chips without an
IOMMU -- in these cases, we need guest physical and true physical to
match, and be contiguous, so static reservation and mapping via /dev/mem
is the most straightforward way to set things up.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Scott Wood 2011-06-14 18:34:39 -05:00 committed by Avi Kivity
parent 59c1f4e35c
commit 9973d54eea
1 changed files with 94 additions and 9 deletions
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103
arch/powerpc/kvm/e500_tlb.c
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@ -270,28 +270,113 @@ static inline void kvmppc_e500_deliver_tlb_miss(struct kvm_vcpu *vcpu,
static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
u64 gvaddr, gfn_t gfn, struct tlbe *gtlbe, int tlbsel, int esel)
{
struct kvm_memory_slot *slot;
struct tlbe *stlbe;
unsigned long pfn;
unsigned long pfn, hva;
int pfnmap = 0;
int tsize = BOOK3E_PAGESZ_4K;
stlbe = &vcpu_e500->shadow_tlb[tlbsel][esel];
/*
* Translate guest physical to true physical, acquiring
* a page reference if it is normal, non-reserved memory.
*
* gfn_to_memslot() must succeed because otherwise we wouldn't
* have gotten this far. Eventually we should just pass the slot
* pointer through from the first lookup.
*/
pfn = gfn_to_pfn(vcpu_e500->vcpu.kvm, gfn);
if (is_error_pfn(pfn)) {
printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
(long)gfn);
kvm_release_pfn_clean(pfn);
return;
slot = gfn_to_memslot(vcpu_e500->vcpu.kvm, gfn);
hva = gfn_to_hva_memslot(slot, gfn);
if (tlbsel == 1) {
struct vm_area_struct *vma;
down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm, hva);
if (vma && hva >= vma->vm_start &&
(vma->vm_flags & VM_PFNMAP)) {
/*
* This VMA is a physically contiguous region (e.g.
* /dev/mem) that bypasses normal Linux page
* management. Find the overlap between the
* vma and the memslot.
*/
unsigned long start, end;
unsigned long slot_start, slot_end;
pfnmap = 1;
start = vma->vm_pgoff;
end = start +
((vma->vm_end - vma->vm_start) >> PAGE_SHIFT);
pfn = start + ((hva - vma->vm_start) >> PAGE_SHIFT);
slot_start = pfn - (gfn - slot->base_gfn);
slot_end = slot_start + slot->npages;
if (start < slot_start)
start = slot_start;
if (end > slot_end)
end = slot_end;
tsize = (gtlbe->mas1 & MAS1_TSIZE_MASK) >>
MAS1_TSIZE_SHIFT;
/*
* e500 doesn't implement the lowest tsize bit,
* or 1K pages.
*/
tsize = max(BOOK3E_PAGESZ_4K, tsize & ~1);
/*
* Now find the largest tsize (up to what the guest
* requested) that will cover gfn, stay within the
* range, and for which gfn and pfn are mutually
* aligned.
*/
for (; tsize > BOOK3E_PAGESZ_4K; tsize -= 2) {
unsigned long gfn_start, gfn_end, tsize_pages;
tsize_pages = 1 << (tsize - 2);
gfn_start = gfn & ~(tsize_pages - 1);
gfn_end = gfn_start + tsize_pages;
if (gfn_start + pfn - gfn < start)
continue;
if (gfn_end + pfn - gfn > end)
continue;
if ((gfn & (tsize_pages - 1)) !=
(pfn & (tsize_pages - 1)))
continue;
gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
pfn &= ~(tsize_pages - 1);
break;
}
}
up_read(&current->mm->mmap_sem);
}
if (likely(!pfnmap)) {
pfn = gfn_to_pfn_memslot(vcpu_e500->vcpu.kvm, slot, gfn);
if (is_error_pfn(pfn)) {
printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
(long)gfn);
kvm_release_pfn_clean(pfn);
return;
}
}
/* Drop reference to old page. */
kvmppc_e500_shadow_release(vcpu_e500, tlbsel, esel);
/* Force TS=1 IPROT=0 TSIZE=4KB for all guest mappings. */
stlbe->mas1 = MAS1_TSIZE(BOOK3E_PAGESZ_4K)
/* Force TS=1 IPROT=0 for all guest mappings. */
stlbe->mas1 = MAS1_TSIZE(tsize)
| MAS1_TID(get_tlb_tid(gtlbe)) | MAS1_TS | MAS1_VALID;
stlbe->mas2 = (gvaddr & MAS2_EPN)
| e500_shadow_mas2_attrib(gtlbe->mas2,