mirror of https://gitee.com/openkylin/linux.git
KVM: X86: Force ASYNC_PF_PER_VCPU to be power of two
Forcing the ASYNC_PF_PER_VCPU to be power of two is much easier to be used rather than calling roundup_pow_of_two() from time to time. Do this by adding a BUILD_BUG_ON() inside the hash function. Another point is that generally async pf does not allow concurrency over ASYNC_PF_PER_VCPU after all (see kvm_setup_async_pf()), so it does not make much sense either to have it not a power of two or some of the entries will definitely be wasted. Signed-off-by: Peter Xu <peterx@redhat.com> Message-Id: <20200416155859.267366-1-peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@ -763,7 +763,7 @@ struct kvm_vcpu_arch {
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struct {
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bool halted;
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gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)];
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gfn_t gfns[ASYNC_PF_PER_VCPU];
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struct gfn_to_hva_cache data;
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u64 msr_val;
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u32 id;
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@ -257,7 +257,7 @@ static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt);
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static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu)
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{
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int i;
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for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU); i++)
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for (i = 0; i < ASYNC_PF_PER_VCPU; i++)
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vcpu->arch.apf.gfns[i] = ~0;
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}
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@ -10310,12 +10310,14 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
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static inline u32 kvm_async_pf_hash_fn(gfn_t gfn)
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{
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BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU));
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return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU));
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}
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static inline u32 kvm_async_pf_next_probe(u32 key)
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{
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return (key + 1) & (roundup_pow_of_two(ASYNC_PF_PER_VCPU) - 1);
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return (key + 1) & (ASYNC_PF_PER_VCPU - 1);
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}
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static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
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@ -10333,7 +10335,7 @@ static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn)
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int i;
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u32 key = kvm_async_pf_hash_fn(gfn);
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for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU) &&
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for (i = 0; i < ASYNC_PF_PER_VCPU &&
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(vcpu->arch.apf.gfns[key] != gfn &&
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vcpu->arch.apf.gfns[key] != ~0); i++)
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key = kvm_async_pf_next_probe(key);
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