From: Vitaly Kuznetsov Date: Tue, 1 Nov 2022 14:53:56 +0000 (+0100) Subject: KVM: x86: hyper-v: Use preallocated buffer in 'struct kvm_vcpu_hv' instead of on... X-Git-Tag: v6.6.17~5910^2~47 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7d5e88d301f84a7b64602dbe3640f288223095ea;p=platform%2Fkernel%2Flinux-rpi.git KVM: x86: hyper-v: Use preallocated buffer in 'struct kvm_vcpu_hv' instead of on-stack 'sparse_banks' To make kvm_hv_flush_tlb() ready to handle L2 TLB flush requests, KVM needs to allow for all 64 sparse vCPU banks regardless of KVM_MAX_VCPUs as L1 may use vCPU overcommit for L2. To avoid growing on-stack allocation, make 'sparse_banks' part of per-vCPU 'struct kvm_vcpu_hv' which is allocated dynamically. Note: sparse_set_to_vcpu_mask() can't currently be used to handle L2 requests as KVM does not keep L2 VM_ID -> L2 VCPU_ID -> L1 vCPU mappings, i.e. its vp_bitmap array is still bounded by the number of L1 vCPUs and so can remain an on-stack allocation. Reviewed-by: Maxim Levitsky Reviewed-by: Sean Christopherson Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini Message-Id: <20221101145426.251680-19-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 89f9c98..4596f19 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -665,6 +665,9 @@ struct kvm_vcpu_hv { } cpuid_cache; struct kvm_vcpu_hv_tlb_flush_fifo tlb_flush_fifo[HV_NR_TLB_FLUSH_FIFOS]; + + /* Preallocated buffer for handling hypercalls passing sparse vCPU set */ + u64 sparse_banks[HV_MAX_SPARSE_VCPU_BANKS]; }; /* Xen HVM per vcpu emulation context */ diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 9898463..058e145 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1906,6 +1906,8 @@ out_flush_all: static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) { + struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); + u64 *sparse_banks = hv_vcpu->sparse_banks; struct kvm *kvm = vcpu->kvm; struct hv_tlb_flush_ex flush_ex; struct hv_tlb_flush flush; @@ -1919,7 +1921,6 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) u64 __tlb_flush_entries[KVM_HV_TLB_FLUSH_FIFO_SIZE - 1]; u64 *tlb_flush_entries; u64 valid_bank_mask; - u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; struct kvm_vcpu *v; unsigned long i; bool all_cpus; @@ -2083,11 +2084,12 @@ static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector, static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) { + struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); + u64 *sparse_banks = hv_vcpu->sparse_banks; struct kvm *kvm = vcpu->kvm; struct hv_send_ipi_ex send_ipi_ex; struct hv_send_ipi send_ipi; u64 valid_bank_mask; - u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; u32 vector; bool all_cpus;