From 9c52f6b3d8c09df75b72dab9a0e6eb2b70435ae1 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 7 Dec 2021 22:09:24 +0000 Subject: KVM: x86: Shove vp_bitmap handling down into sparse_set_to_vcpu_mask() Move the vp_bitmap "allocation" that's needed to handle mismatched vp_index values down into sparse_set_to_vcpu_mask() and drop __always_inline from said helper. The need for an intermediate vp_bitmap is a detail that's specific to the sparse translation with mismatched VP<=>vCPU indexes and does not need to be exposed to the caller. Regarding the __always_inline, prior to commit f21dd494506a ("KVM: x86: hyperv: optimize sparse VP set processing") the helper, then named hv_vcpu_in_sparse_set(), was a tiny bit of code that effectively boiled down to a handful of bit ops. The __always_inline was understandable, if not justifiable. Since the aforementioned change, sparse_set_to_vcpu_mask() is a chunky 350-450+ bytes of code without KASAN=y, and balloons to 1100+ with KASAN=y. In other words, it has no business being forcefully inlined. Signed-off-by: Sean Christopherson Reviewed-by: Vitaly Kuznetsov Message-Id: <20211207220926.718794-7-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/hyperv.c | 65 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 27 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index bc14c3d0c0cc..e46f267585f4 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1713,32 +1713,47 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) return kvm_hv_get_msr(vcpu, msr, pdata, host); } -static __always_inline unsigned long *sparse_set_to_vcpu_mask( - struct kvm *kvm, u64 *sparse_banks, u64 valid_bank_mask, - u64 *vp_bitmap, unsigned long *vcpu_bitmap) +static void sparse_set_to_vcpu_mask(struct kvm *kvm, u64 *sparse_banks, + u64 valid_bank_mask, unsigned long *vcpu_mask) { struct kvm_hv *hv = to_kvm_hv(kvm); + bool has_mismatch = atomic_read(&hv->num_mismatched_vp_indexes); + u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; struct kvm_vcpu *vcpu; int bank, sbank = 0; unsigned long i; + u64 *bitmap; + + BUILD_BUG_ON(sizeof(vp_bitmap) > + sizeof(*vcpu_mask) * BITS_TO_LONGS(KVM_MAX_VCPUS)); + + /* + * If vp_index == vcpu_idx for all vCPUs, fill vcpu_mask directly, else + * fill a temporary buffer and manually test each vCPU's VP index. + */ + if (likely(!has_mismatch)) + bitmap = (u64 *)vcpu_mask; + else + bitmap = vp_bitmap; - memset(vp_bitmap, 0, - KVM_HV_MAX_SPARSE_VCPU_SET_BITS * sizeof(*vp_bitmap)); + /* + * Each set of 64 VPs is packed into sparse_banks, with valid_bank_mask + * having a '1' for each bank that exists in sparse_banks. Sets must + * be in ascending order, i.e. bank0..bankN. + */ + memset(bitmap, 0, sizeof(vp_bitmap)); for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, KVM_HV_MAX_SPARSE_VCPU_SET_BITS) - vp_bitmap[bank] = sparse_banks[sbank++]; + bitmap[bank] = sparse_banks[sbank++]; - if (likely(!atomic_read(&hv->num_mismatched_vp_indexes))) { - /* for all vcpus vp_index == vcpu_idx */ - return (unsigned long *)vp_bitmap; - } + if (likely(!has_mismatch)) + return; - bitmap_zero(vcpu_bitmap, KVM_MAX_VCPUS); + bitmap_zero(vcpu_mask, KVM_MAX_VCPUS); kvm_for_each_vcpu(i, vcpu, kvm) { if (test_bit(kvm_hv_get_vpindex(vcpu), (unsigned long *)vp_bitmap)) - __set_bit(i, vcpu_bitmap); + __set_bit(i, vcpu_mask); } - return vcpu_bitmap; } struct kvm_hv_hcall { @@ -1775,9 +1790,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool struct kvm *kvm = vcpu->kvm; struct hv_tlb_flush_ex flush_ex; struct hv_tlb_flush flush; - u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; - DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS); - unsigned long *vcpu_mask; + DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS); u64 valid_bank_mask; u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; bool all_cpus; @@ -1870,11 +1883,9 @@ do_flush: if (all_cpus) { kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH_GUEST); } else { - vcpu_mask = sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, - vp_bitmap, vcpu_bitmap); + sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask); - kvm_make_vcpus_request_mask(kvm, KVM_REQ_TLB_FLUSH_GUEST, - vcpu_mask); + kvm_make_vcpus_request_mask(kvm, KVM_REQ_TLB_FLUSH_GUEST, vcpu_mask); } ret_success: @@ -1907,9 +1918,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool struct kvm *kvm = vcpu->kvm; struct hv_send_ipi_ex send_ipi_ex; struct hv_send_ipi send_ipi; - u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; - DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS); - unsigned long *vcpu_mask; + DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS); unsigned long valid_bank_mask; u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; u32 vector; @@ -1965,11 +1974,13 @@ check_and_send_ipi: if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR)) return HV_STATUS_INVALID_HYPERCALL_INPUT; - vcpu_mask = all_cpus ? NULL : - sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, - vp_bitmap, vcpu_bitmap); + if (all_cpus) { + kvm_send_ipi_to_many(kvm, vector, NULL); + } else { + sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask); - kvm_send_ipi_to_many(kvm, vector, vcpu_mask); + kvm_send_ipi_to_many(kvm, vector, vcpu_mask); + } ret_success: return HV_STATUS_SUCCESS; -- cgit v1.2.3