Re: [PATCH 04/11] powerpc/kvm: Don't store values derivable from HPT order
From: Thomas Huth <hidden>
Date: 2016-12-16 10:39:50
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kvm, lkml
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 <redacted> ---
[...]
quoted hunk ↗ jump to hunk
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.
quoted hunk ↗ jump to hunk
@@ -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 <redacted>