On Fri, Dec 16, 2016 at 11:39:26AM +0100, Thomas Huth wrote:
> On 15.12.2016 06:53, David Gibson wrote:
> > Currently the kvm_hpt_info structure stores the hashed page table's order,
> > and also the number of HPTEs it contains and a mask for its size. The
> > last two can be easily derived from the order, so remove them and just
> > calculate them as necessary with a couple of helper inlines.
> >
> > Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> > ---
> [...]
> > diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> > index b5799d1..fe88132 100644
> > --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> > +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> > @@ -83,15 +83,11 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
> >
> > kvm->arch.hpt.virt = hpt;
> > kvm->arch.hpt.order = order;
> > - /* HPTEs are 2**4 bytes long */
> > - kvm->arch.hpt.npte = 1ul << (order - 4);
> > - /* 128 (2**7) bytes in each HPTEG */
> > - kvm->arch.hpt.mask = (1ul << (order - 7)) - 1;
> >
> > atomic64_set(&kvm->arch.mmio_update, 0);
> >
> > /* Allocate reverse map array */
> > - rev = vmalloc(sizeof(struct revmap_entry) * kvm->arch.hpt.npte);
> > + rev = vmalloc(sizeof(struct revmap_entry) * kvmppc_hpt_npte(&kvm->arch.hpt));
> > if (!rev) {
> > pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n");
> > goto out_freehpt;
> > @@ -194,8 +190,8 @@ void kvmppc_map_vrma(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot,
> > if (npages > 1ul << (40 - porder))
> > npages = 1ul << (40 - porder);
> > /* Can't use more than 1 HPTE per HPTEG */
> > - if (npages > kvm->arch.hpt.mask + 1)
> > - npages = kvm->arch.hpt.mask + 1;
> > + if (npages > kvmppc_hpt_mask(&kvm->arch.hpt) + 1)
> > + npages = kvmppc_hpt_mask(&kvm->arch.hpt) + 1;
> >
> > hp0 = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
> > HPTE_V_BOLTED | hpte0_pgsize_encoding(psize);
> > @@ -205,7 +201,8 @@ void kvmppc_map_vrma(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot,
> > for (i = 0; i < npages; ++i) {
> > addr = i << porder;
> > /* can't use hpt_hash since va > 64 bits */
> > - hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & kvm->arch.hpt.mask;
> > + hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25)))
> > + & kvmppc_hpt_mask(&kvm->arch.hpt);
> > /*
> > * We assume that the hash table is empty and no
> > * vcpus are using it at this stage. Since we create
>
> kvmppc_hpt_mask() is now called three times in kvmppc_map_vrma() ... you
> could use a local variable to store the value so that the calculation
> has only be done once here.
Well, I was assuming that inlining plus gcc's common subexpression
elimination would deal with that.
>
> > @@ -1306,7 +1303,7 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf,
> >
> > /* Skip uninteresting entries, i.e. clean on not-first pass */
> > if (!first_pass) {
> > - while (i < kvm->arch.hpt.npte &&
> > + while (i < kvmppc_hpt_npte(&kvm->arch.hpt) &&
> > !hpte_dirty(revp, hptp)) {
> > ++i;
> > hptp += 2;
> > @@ -1316,7 +1313,7 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf,
> > hdr.index = i;
> >
> > /* Grab a series of valid entries */
> > - while (i < kvm->arch.hpt.npte &&
> > + while (i < kvmppc_hpt_npte(&kvm->arch.hpt) &&
> > hdr.n_valid < 0xffff &&
> > nb + HPTE_SIZE < count &&
> > record_hpte(flags, hptp, hpte, revp, 1, first_pass)) {
> > @@ -1332,7 +1329,7 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf,
> > ++revp;
> > }
> > /* Now skip invalid entries while we can */
> > - while (i < kvm->arch.hpt.npte &&
> > + while (i < kvmppc_hpt_npte(&kvm->arch.hpt) &&
> > hdr.n_invalid < 0xffff &&
> > record_hpte(flags, hptp, hpte, revp, 0, first_pass)) {
> > /* found an invalid entry */
>
> Dito, you could use a local variable to store the value from
> kvmppc_hpt_npte()
>
> Anyway, apart from these nits, patch looks fine to me, so:
>
> Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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